U.S. patent application number 09/748581 was filed with the patent office on 2001-05-24 for roof tile construction using sandwiched adhesive.
Invention is credited to Starr, Cris Damon.
Application Number | 20010001404 09/748581 |
Document ID | / |
Family ID | 23233161 |
Filed Date | 2001-05-24 |
United States Patent
Application |
20010001404 |
Kind Code |
A1 |
Starr, Cris Damon |
May 24, 2001 |
Roof tile construction using sandwiched adhesive
Abstract
A roof construction uses a one-component adhesive to adhere roof
tiles to a roof. The adhesive is formed in a U-shaped pattern in
that the adhesive is dispensed in a bottom leg deposit on the
tile's underside, a bight deposit extending about the tile's
leading edge and a top adhesive deposit overlying the bottom
deposit and extending on the outside surface of the tile. As the
tiles are laid onto the roof in an overlying fashion, the U-shaped
adhesive is sandwiched between the tile, the overlying tile and the
roof forming sealing contact therewith and therebetween.
Inventors: |
Starr, Cris Damon; (Cape
Coral, FL) |
Correspondence
Address: |
FRANK J. NAWALANIC
Suite 304
1422 Euclid Avenue
Cleveland
OH
44115
US
|
Family ID: |
23233161 |
Appl. No.: |
09/748581 |
Filed: |
December 22, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09748581 |
Dec 22, 2000 |
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09317325 |
May 24, 1999 |
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Current U.S.
Class: |
156/71 |
Current CPC
Class: |
E04D 1/2916 20190801;
E04D 2001/3473 20130101; E04D 1/2918 20190801; E04D 1/34 20130101;
E04D 2001/3435 20130101; E04D 2001/3494 20130101; E04D 1/29
20190801; E04D 12/002 20130101; E04D 2001/3482 20130101; E04D
2001/3497 20130101 |
Class at
Publication: |
156/71 |
International
Class: |
E04F 013/00 |
Claims
Having thus defined the invention, it is claimed:
1. A method for applying roof tiles with one-component,
polyurethane adhesive to a roof, each roof tile having opposing
leading and trailing edges intersecting with opposing side marginal
edges, an underside surface adapted to face the roof and an outside
surface adapted to face the elements when the roof tile is
installed on the roof, said method comprising the acts of: a)
dispensing for each tile, the adhesive as a bead in a contiguous
integral U-shaped, pattern having top and bottom adhesive leg
deposits extending from the leading edge a distance towards the
trailing edge adjacent the upper and underside surfaces,
respectively, of the tile and a bight adhesive deposit adjacent to
and extending away from the leading edge, but integral with and
connecting the top and bottom leg deposits; b) positioning an upper
tile to partially overlie an immediately adjacent lower tile in
that the upper tile's leading edge is adjacent the roof while the
upper tile's trailing edge extends past the leading edge of an
immediately adjacent lower tile so that the U-shaped pattern of the
lower tile is sandwiched between roof tiles and roof by i) its
bottom deposit in contact with the roof and the underside of the
lower tile; ii) its top deposit in contact with the outside surface
of the lower tile and the underside surface of the upper tile and
iii) its bight deposit in contact with the roof, the underside
surface of the upper tile and the leading edge of the lower tile;
and pressing the upper tile against the roof and lower tile to
cause the adhesive in the U-shaped sandwiched pattern to spread out
into additional sealing contact areas while the tile is vertically
aligned with an adjacent tile at a desired spaced distance from the
roof; c) laying tiles side by side while repeating acts (a) and (b)
for each placed tile to form a longitudinally extending tile
course, each course, with the exception of the lowest first course,
overlying a lower course, and each course, with the exception of
the last, highest course, being overlaid by a higher course
whereby, with the exception of the first and last courses, the
tiles are secured to the roof by placing a single U-shaped pattern
on each tile which becomes sandwiched into sealing contact with the
roof and adjacent tiles as the tiles are laid into position; and,
d) thereafter, bonding the tiles to the roof after the polyurethane
adhesive has cured.
2. The method of claim 1 wherein said act of dispensing includes
the act of continuously dispensing the leg deposits and the bight
deposit onto any given tile.
3. The method of claim 2 wherein the pattern is deposited onto any
given tile before the tile is placed onto the roof.
4. The method of claim 2 wherein any given tile is positioned to
overlie a lower tile and contact the U-shaped pattern on the lower
tile before the U-shaped pattern is formed on the given tile.
5. The method of claim 4 wherein the given tile is held at its
leading edge away from said roof while the bottom adhesive deposit
of the pattern is dispensed between the underside of the given tile
and roof.
6. The method of claim 1 wherein the bottom deposit of the pattern
is dispensed on the roof prior to positioning any given tile to
overlie a lower tile and the top deposit and bight deposit is
formed after the given tile is positioned over a lower tile to
contact the top deposit of the lower tile's U-shaped pattern but
before the open time of the one component adhesive has expired so
that the bight portion is contiguous with the top and bottom leg
portions without visible knit lines being formed.
7. The method of claim 1 wherein the tiles are selected from the
group of tiles consisting of high profile tiles having a non-planar
exterior configuration, low profile tiles having a generally
non-planar exterior configuration and flat tiles having a generally
planar exterior configuration.
8. The method of claim 1 wherein the roof has a plurality of
longitudinally extending, vertically spaced batten strips, the tile
has an anchor lug extending from its underside adjacent to its
leading edge and the positioning act including placing a given tile
in overlying relationship to a lower tile by resting the lug of the
given tile on a batten strip.
9. The method of claim 8 wherein the U-shaped pattern is formed by
dispensing the one-component adhesive in the bottom deposit after
any give tile has been positioned over an underlying tile to
contact the U-shaped pattern of the lower tile.
10. The method of claim 1 wherein the adhesive is a low density,
moisture cured one-component, polyurethane froth expanding, after
being initially dispensed as a froth, to no more than about 50% of
its volume after being initially dispensed.
11. The method of claim 10 wherein said froth expands to no more
than about 20% of its volume after being dispensed.
12. The method of claim 1 wherein the roof includes a substrate,
the tiles being positioned on said substrate.
13. The method of claim 1 wherein the distance a given tile's
trailing edge extends below a lower tile's leading edge is an
overlap, and depositing the top deposit of the lower tile's
U-shaped pattern a distance extending from the lower tile's leading
edge not greater than the overlap.
14. The method of claim 13 wherein the top and bottom leg deposits
of any given pattern may be dispensed anywhere between the marginal
edges of any given tile.
15. The method of claim 14 wherein the act of laying the tiles in
longitudinally extending tile courses places the tiles in any given
course longitudinally offset from the tiles in an immediately
adjacent upper and lower course by a distance approximately equal
to one-half the distance between the tile's opposing side margin
edges; the tiles having a generally flat profile and the U-shaped
pattern being dispensed at approximately the midpoint of the
distance between opposing side margins of each tile whereby each
tile is secured to the roof at positions adjacent the midpoint of
its top leading edge and adjacent each corner of its bottom
trailing edge.
16. The method of claim 14 wherein the U-shaped pattern is
consistently applied about the top leading edge of each tile at a
set position between the opposing side margin edges of the tile and
the tiles in any given tile course are longitudinally aligned with
tiles in courses immediately above and below the given course of
tiles such that the adhesive patterns are generally in vertical
alignment over the roof area.
17. The method of claim 1 further including the act of dispensing
an additional adhesive deposit situated between the roof and the
underside of the tiles in the first, lowermost course at a position
spaced from the U-shaped sandwich pattern and closer to the
trailing edge of the tiles in the first tile course.
18. The method of claim 17 wherein said additional adhesive deposit
includes two pads of adhesive for each tile when the tiles are flat
tiles.
19. The method of claim 1 wherein said act of dispensing said
U-shaped pattern comprises the acts of dispensing the bottom leg
deposit prior to positioning a given tile to overlie a lower tile
and after positioning the given tile to contact the top leg and
bight portions of the lower tile, dispensing a bead of adhesive
over the outer surface of the given tile which extends over and
away from the leading edge of the given tile to form the top leg
and bight portion of the U-shaped pattern for the given tile before
the open time of the adhesive has lapsed so that the bight portion
of the one-component adhesive is contiguous with the top and bottom
leg portions without the presence of any visible knit lines.
20. The method of claim 1 wherein prior to pressing or laying the
tiles onto the adhesive, the adhesive is dispensed to form the top
and bottom leg portions of the U-shaped adhesives as a bead having
a length extending from the leading edge towards the trailing edge
of about 11/2to 21/2; a width extending between opposing side
margins of about 4" to about 5" and a height of about 1" to about
11/2".
21. The method of claim 20 wherein the bight portion of the
dispensed adhesive has a length extending beyond the leading edge
of a given tile of about 1" to 2"; a width of about 31/2" to about
5"; and a height of about 2" to about 21/2" plus the thickness of
the tile.
22. The method of claim 21 wherein each U-shaped sandwich pattern
has a weight of about 9 to 15 grams.
23. The method of claim 22 wherein each U-shaped adhesive pattern
has a weight of about 12 to 14 grams.
24. The method of claim 21 wherein each U-shaped adhesive pattern
contacts the roof over an area of about 9 in.sup.2 to about 13
in.sup.2 when the tile is pressed against the roof to position the
tile at a set vertical distance from the roof.
25. The method of claim 1 wherein the one-component adhesive is a
low density one-component polyurethane adhesive having a density of
about 0.8 to about 4.0 lbs/ft when initially dispensed as a
froth.
26. The method of claim 25 wherein said low density polyurethane
adhesive has a density of about 1.1 to about 2.5 lbs/ft.
27. The method of claim 26 wherein said U-shaped pattern has a
weight of about 9 to 15 grams.
28. The method of claim 27 wherein said U-shaped pattern has a
weight of about 12-14 grams.
29. The method of claim 28 wherein said U-shaped adhesive is in
sealing contact with the roof over an area of from about 9 to about
13 in.sup.2 when the tile has an underside area of about 1 to about
1.5 ft.sup.2.
30. A method for installing roof tiles onto a roof comprising the
acts of: providing a supply of one-component adhesive foam;
providing a supply of roof tiles for attachment to said roof, each
of the roof tiles having opposing leading and trailing edges
interconnected by side edges, each of said roof tiles having an
undersurface which opposes said roof when installed thereon and an
outside surface substantially exposed to the elements; choosing a
set of first roof tiles from said roof tile supply; dispensing at
least a first deposit of adhesive foam spaced from but adjacent to
the trailing edge of each first tile and a second, deposit in the
form of a U-shaped pattern of adhesive foam extending around the
leading edge of each first tile; placing said first roof tiles onto
said roof in a course so that said trailing edges of said first
roof tiles are positioned closer to an eave of said roof than said
first roof tiles leading edges and laying said first roof tiles
onto said roof so that contact is effected between said first
deposit, said roof and said underside of the first tiles and
between said roof and the adhesive in a bottom leg portion of the
U-shaped pattern and the underside of the first roof tiles and
between said adhesive in a bight portion of the U-shaped pattern
and said roof; choosing a set of second roof tiles from said roof
tile supply; dispensing the U-shaped pattern of said adhesive foam
from said adhesive foam supply about the leading edge of said
second tiles; placing said second roof tiles onto said roof either
before or after the U-shaped pattern has been formed so that said
trailing edges of said second roof tiles are positioned over said
leading edges of said first roof tiles and said leading edges of
said second roof tiles are positioned over said roof and laying
said second roof tiles onto said roof and said first roof tiles
after the U-shaped pattern has been formed so that contact is
effected a) between the roof and the underside of the second tiles
and the adhesive in said bottom leg portion of said second roof
tiles' U-shaped pattern and b) between the underside of said second
roof tiles, said outside of said first roof tiles and the adhesive
in said top leg portion of said first tiles' U-shaped pattern and
c) between the underside of said second tile, the roof and the
adhesive in the bight portion of the first tiles' U-shaped pattern;
choosing a set of subsequent roof tiles from said roof tile supply;
dispensing said adhesive foam in the U-shaped pattern about the
leading edge of said subsequent tiles; placing said subsequent roof
tiles onto said roof so that leading edges of said subsequent roof
tiles are positioned over said roof and trailing edges of said
subsequent roof tiles are positioned over a preceding set of roof
tiles, and laying said subsequent tiles onto said roof so that
contact is effected a) between said roof and said underside of said
subsequent tiles and the adhesive in said bottom leg portion of
said subsequent tiles' U-shaped pattern and b) between said
underside of said subsequent roof tiles, said outside of said tiles
being overlapped and the adhesive in said top leg portion of said
U-shaped pattern of the tiles being overlapped by said subsequent
tiles and c) between the underside of said subsequent tiles, said
roof and the adhesive in said bight portion of the tiles being
overlapped by said subsequent tiles; and, allowing said first,
second and subsequent discontinuous patterns to cure to bond said
first, second and subsequent roof tiles to said roof.
31. The method of claim 30 wherein said U-shaped pattern is formed
on any given tile in the second and subsequent courses by
dispensing a bead of adhesive comprising said bottom leg of said
pattern onto said roof and dispensing a second bead, after said
tile has been laid over a lower tile and placed onto said roof so
that its leading edge is in contact with said bottom leg adhesive,
onto said outer surface of said given tile, said second bead being
dispensed before the open time of said first bead has lapsed and
extending past and beyond said leading edge of said given tile to
contact, meld with and fuse into said first bead adjacent said
leading edge of said given tile to form a contiguous, enveloping
pattern about said leading edge without the presence of any visible
knit lines in said U-shaped pattern.
32. The method of claim 30 wherein said U-shaped pattern is formed
by continuously applying a bead of adhesive extending from said
underside of any given tile, around said leading edge of said given
tile and on said outside surface of said given tile.
33. The method of claim 30 wherein any given tile in said second
and subsequent courses is initially laid so that its trailing edge
overlies a lower tile with a portion of said underside surface in
contact with said U-shaped adhesive pattern of said lower tile,
said method further including the act thereafter of continuously
forming said U-shaped pattern for the given tile by dispensing a
bead of adhesive from the underside of said given tile, around the
leading edge of said given tile and onto said outside surface of
the tile or, from said outside surface of said given tile, about
said leading edge of said given tile to the space between the
underside of said given tile and said roof.
34. The method of claim 33 further including the act of raising
said leading edge of said given tile to dispense said bottom leg of
said adhesive U-shaped pattern.
35. A method of installing roof tiles onto a roof, the roof tiles
having opposing trailing and leading edges intersecting opposing
side edges, and underside and outside surfaces, the method
comprising the acts of: dispensing a one-component, polyurethane
froth in a U-shaped pattern extending from the underside of any
given tile, around the leading edge of the given tile to the
outside of the given tile, and placing the tile in overlapping
relationship to a lower tile whereby the adhesive on the underside
of the given tile contacts the roof adjacent the leading edge of
the given tile while the underside of the given tile adjacent the
trailing edge contacts the adhesive pattern dispensed on the lower
tile to establish sealing contact between the underside of the
given tile adjacent its trailing edge with the outside of the lower
tile and between the underside of the given tile adjacent its
leading edge with the roof.
36. The method of claim 35 further including the act of processing
the given tile towards the roof to set the tile at a desired
vertical distance from the roof while causing the U-shaped pattern
to expand into a longer area in contact with the roof and tile and
thereafter abandoning the tile to the roof and the underlying tile
when the foam cures.
37. The method of claim 36 wherein the U-shaped pattern is formed
on any given tile by dispensing a bead of adhesive comprising the
bottom leg of the pattern onto the roof and dispensing a second
bead of adhesive onto the given tile's outer surface, after the
given tile has been positioned over a lower tile and onto the roof
so that its leading edge is in contact with the bottom leg adhesive
but before the open time of the adhesive has lapsed, said second
bead being dispensed past and beyond the leading edge of the given
tile to contact, meld with and fuse into said first bead adjacent
said leading edge of said given tile whereby a contiguous U-shaped
pattern without visible knit lines and which pattern an be flowed
into a longer contact area during the tile pressing act.
38. The method of claim 36 wherein said U-shaped pattern is formed
by continuously applying a single bead of adhesive extending from
the underside of any given tile, around and enveloping the leading
edge of the given tile and onto the outside surface of the given
tile.
39. The method of claim 38 wherein any given tile is initially
positioned so that its trailing edge overlies a lower tile with a
portion of the given tile's underside surface in contact with the
U-shaped adhesive pattern of the lower tile, the method further
including the act thereafter of forming the U-shaped pattern for
the given tile by dispensing a continuous bead of adhesive from the
underside of the given tile, around the leading edge of the given
tile and onto the outside surface of the tile or, from the outside
surface of the given tile, about the leading edge of the given tile
to the space between the underside of the given tile and the
roof.
40. The method of claim 39 further including the act of raising the
leading edge of the given tile to dispense the bottom leg of the
adhesive U-shaped pattern.
41. In a roof having a substrate, an underlayment covering the
substrate and a plurality of roof tiles adhesively affixed to said
substrate, the improvement comprising: each roof tile being affixed
to said roof by a one-component adhesive applied to individual roof
tiles of said plurality of roof tiles in a U-shaped, continuous
sandwiched pattern, one pattern for one roof tile, the pattern
including a bottom leg adhesive deposit between the underside of
any given roof tile and the roof substrate, a top leg adhesive
deposit between the outside of the given tile and the underside of
an overlying tile and a connecting bight adhesive deposit extending
beyond the leading edge of the given tile and vertically extending
between the underside of the overlying tile and the roof
substrate.
42. The improved roof of claim 41 wherein said individual roof
tiles are one or more tiles selected from the group consisting of
flat tiles having a planar exterior configuration, high profile
tiles having a non-planar exterior configuration and low profile
tiles having a generally non-planar exterior configuration.
43. The improved roof of claim 42 wherein the one-component
adhesive is a low density polyurethane foam having a density of
between 0.8 to 4.0 lbs/ft.
44. The improvement of claim 43 wherein the area contacted by the
U-shaped pattern between the roof and the underside of a given tile
is about 10 in.sup.2.
Description
[0001] This invention relates to roof construction and more
particularly to a system, method and apparatus, for securing roof
tiles to a roof.
[0002] The invention is particularly applicable to and will be
described with specific reference to a roof construction using a
one-component, polyurethane adhesive froth to attach any
conventional roof tile to a roof. However, those skilled in the art
will recognize that the invention has broader application and
conceivably, could be used with two-component, polyurethane foam
adhesives.
INCORPORATION BY REFERENCE
[0003] The following patents are incorporated herein by reference
and made a part hereof:
[0004] My U.S. Pat. No. 5,895,536, issued Apr. 20, 1999, entitled
"METHOD OF ADHERING ROOF TILES USING ONE-COMPONENT ADHESIVE AND
ROOF CONSTRUCTION OBTAINED THEREBY" and U.S. Pat. No. 5,362,342, to
Murray et al., issued Nov. 8, 1994, entitled "METHOD OF BONDING
ROOF TILES TO ROOF SUBSTRATE UTILIZING URETHANE FOAM".
[0005] Neither patent incorporated by reference herein forms any
part of this invention. The material is incorporated by reference
so that the detailed description of this invention need not set
forth in detail prior art construction techniques and methods known
in the art as explained in the patents listed above.
BACKGROUND
[0006] Roof construction, particularly residential roof
construction, varies by climatic location throughout the United
States. This invention relates to protective roof coverings formed
by roof tiles as opposed to asphalt based roof shingles typically
used in the northern parts of the United States to form a
protective roof covering. Roof tiles are typically constructed from
natural materials such as clay, concrete, stone, ceramics
(including brick and fired clay) and have also been made of
synthetic material, typically plastic and it is possible to have
tiles formed from combinations of natural and synthetic materials,
i.e., fibrous cement.
[0007] Traditionally, in the United States, roof tiles have been
applied with a cementitious material, typically mortar usually
mixed at the site. The prior art patents incorporated by reference
discuss at length inherent problems encountered when mortar is used
to affix roof tiles to the roof substrate and those problems will
not be restated herein. However, the prior art patents have not
discussed mortar patterns used to affix the roof tiles to the roof.
While it may have been conventional at one time to simply place the
mortar on the underside of the roof tile, without regard to mortar
amount, building construction regulations such as those promulgated
by Southern Building Code, Florida, require that no more than 33%
of the area underneath the tile be covered by the adhering
material. This leaves the space between tiles and between roof and
tiles open for air circulation so that the tiles are less likely to
be pulled off the roofs during hurricane winds. Accordingly,
conventional practice today is to trowel a glob or pad of mortar
over the central underside area of the tile (or alternatively, a
deposit of the mortar is placed on the roof), which is then
flattened somewhat when the tile is positioned onto the roof
substrate. Again, the height and area of the mortar pad is such
that no more than 33% of the area of the tile is to be covered by
the cementitious material. In practice, it sometimes occurs that
too little or too much mortar is used which, coupled with the well
known adhesive inconsistencies of mortar, results in faulty tile
application.
[0008] Because of the limitations of conventional cementitious
materials, specifically mortar, other types of materials,
principally adhesives, have been investigated for use as bonding
agents to affix roof tiles to the roof substrate without the need
for mechanical fasteners.
[0009] A) U.S. Chronology.
[0010] Accordingly, at least as early as the summer of 1992, I
purchased an off-the-shelf, commercially available, one-component,
polyurethane foam in a pressurized aerosol spray type container.
The polyurethane foam was applied as a deposit in the shape of a
centrally positioned pad, replicating the conventional mortar pad
shape and position, and used to affix the roof tiles to the roof.
It was found that the polyurethane foam would act as an adhesive
fixing the tile to the roof substrate. However, the expansion of
the foam lifted the tile as the foam cured and it was believed that
the strength of the adhesive bond had to be thoroughly investigated
as well as formulations addressing the tile lifting before a
commercial product could be offered. Through my employer at that
time, Life Tile (a subsidiary of Boral Concrete Products), a number
of polyurethane foam companies were contacted to determine if there
was an interest in pursuing a joint test program utilizing
polyurethane foam as a roof tile adhesive. One company, Poly-Foam
Products, Inc. expressed an interest in the roof tile application
and I worked with that company commencing in the spring of 1993 on
a program which resulted in the development of a two-component,
polyurethane roof tile adhesive as disclosed in U.S. Pat. No.
5,362,342, incorporated by reference herein. As is well known,
two-component, polyurethane foam is significantly different from a
one-component, polyurethane foam. For instance, the chemical
reaction of the formulation in a two-component foam occurs when the
"A" side (isocyanate) contacts the "B" side whereas a
one-component, polyurethane foam undergoes a pre-polymerization
reaction within the container and utilizes moisture to effect
foaming or frothing as well as curing of the polyurethane. The
formulations are markedly different and traditionally the foams,
even when sold for the same application, have different
characteristics. For example, the two-component foam generally will
not expand to the extent of a one-component foam after it has
initially foamed on mixing. On the other hand, because of the A/B
reaction, a two-component foam will generally have a quicker tack
time or shorter open time than a one-component foam. Chemical
formulations of the foam, however, can significantly vary such
characteristics. In any event, the two-component foam adhesive
described in the '342 patent places an adhesive bead extending the
length of the tile. While this placement pattern has been tested
and approved by the Southern Building Code, Florida for use as a
roof-tile adhesive, placing the foam in a bead running the length
of the tile is an excessive use of adhesive foam resulting in a
higher cost to the roofing contractor than what otherwise is
required. Additionally, the two-component application requiring two
separate pressurized containers of chemicals, is somewhat unwieldy
for use in roofing residential dwellings, especially if the roof
pitch is steep.
[0011] In late 1995, I began testing a one-component, polyurethane
foam supplied by Insta-Foam, Inc. and developed an adhesive pattern
to minimize the use of the foam as described in my U.S. Pat. No.
5,895,536. The '536 patent discloses placing two discrete foam
deposits (approximately the diameter of a tennis ball) at
diagonally opposing comers of the roof tile. As shown in all the
embodiments of my patent, one deposit is placed at the leading edge
corner of the tile between the roof substrate and the tile
underside while the other foam deposit is placed at the trailing
edge corner between the outside surface of the lower tile (which
the upper tile overlaps) and the underside surface of the upper
tile. While less adhesive is used in the system disclosed in the
'536 patent when compared to the adhesive used in the system of the
'342 patent, two separate deposits are required per tile and only
one deposit per tile extends between the roof and tile. This
placement fundamentally limits the adhesion ability of the roof
system. However, the use of small paddy sizes addressed the issues
of tile displacement resulting from expansion during curing at
least to the extent that noticeable tile displacement did not occur
if the adhesive was properly applied.
[0012] The above represents what is believed a chronological
development of the utilization of polyurethane foam as a roof tile
adhesive in the United States and this is believed consistent with
approvals given by building code regulatory agencies of Dade
County, Florida which has approved the use of polyurethane foam
when placed in a pattern as described in the '342 and '536
patents.
[0013] B) Europe.
[0014] In Europe, polyurethane foam has long been used to secure
roof tiles. For example, an especially fabricated roofing tile
having recesses for receiving polyurethane foam is disclosed in UK
patent application No. GB 2169329 A, published Jul. 9, 1986. The
assignee's sister company has sold a general purpose,
one-component, polyurethane foam for use in adhering roof tiles to
roofs. A published application of a one-component foam sold in
Europe is to place a bead adjacent the leading edge on the outside
surface of one tile contacting the trailing edge of the underside
surface of a higher tile. Another common application of
polyurethane foam is to spray the foam from the inside of the
building to fill any cracks between tiles as well as to secure the
tiles to longitudinally extending rafters. It is believed that
European companies, including assignee's sister company, have sold
one-component foams for roofing applications since as early as
1988.
[0015] C) Adhesive Application.
[0016] Apart from polyurethane foams, special roof tile adhesives
have been developed for securing roof tiles to the roof substrate.
In particular, Ohio Sealants, Inc. has developed a roof tile
adhesive marketed under its Pro Series.RTM. RT600 brand name which
has been certified by Dade County for repair of existing roof
tiles. Specifically, certified repairs require the removal or the
lifting of an existing loose tile sufficient to enable the
application of a minimum 1".times.1" bead of adhesive to the
existing mortar pad so that both the mortar pad and the under side
of the tile are in contact with adhesive and in addition, a 3/8"
thick by 2" long bead of adhesive must be applied to the head of
the previous tile. Generally, specially formulated, one component,
roof sealing adhesives are sold in caulk-type containers which are
suitable for repairing existing tiles as opposed to laying courses
of tiles covering the entire roof.
SUMMARY OF THE INVENTION
[0017] Accordingly, it is a principal object of the present
invention to provide a roof construction, preferably using a
one-component, polyurethane froth, which deposits a single adhesive
pattern per roof tile in a manner which increases the strength of
the bond between tile and roof while using a minimal amount of
adhesive.
[0018] This object, along with other features of the invention, is
achieved in a method for applying roof tiles to a roof with
one-component, polyurethane adhesive where each roof tile has
opposing leading and trailing edges intersecting with opposing side
edges, an underside surface adapted to face the roof and an outside
surface adapted to face the elements when the tile is installed on
the roof. The method includes the acts of dispensing, for each
tile, the adhesive in an integral, U-shaped, sandwich pattern. The
sandwich pattern has top and bottom adhesive leg deposits extending
from the tile's leading edge a distance towards the trailing edge
adjacent the tile's outside and underside surfaces, respectively,
and a bight adhesive deposit adjacent to and extending away from
the leading edge but integral with and connecting the top and
bottom leg deposits. The method includes positioning an upper tile
to partially overlie an immediately adjacent lower tile so that the
upper tile's leading edge is adjacent the roof while the upper
tile's trailing edge extends past the leading edge of an
immediately adjacent lower tile whereby the U-shape pattern of the
lower tile is sandwiched because i) its bottom leg deposit is in
contact with the roof and the underside of the lower tile, ii) its
top leg deposit is in contact with the outside surface of the lower
tile and the underside surface of the upper tile and iii) its bight
portion is in contact with the roof, the underside surface of the
upper tile and the leading edge of the lower tile thereby
establishing adhesive contact between the roof and both tiles at
positions adjacent the leading and trailing edge of the tiles. The
method includes covering the roof by laying tiles side by side
while repeating the dispensing and positioning acts for each placed
tile to form longitudinally extending tile courses, each course,
with the exception of the lowest first course, overlying a lower
tile course and each course, with the exception of the last,
highest course, being overlaid by a higher course whereby, with the
exception of the first and last courses, the tiles are secured to
the roof by depositing a single, U-shaped sandwich pattern on each
tile.
[0019] In accordance with another aspect of the invention, the
U-shaped sandwich adhesive pattern may be formed in several
different ways. In one embodiment, the U-shaped sandwich pattern is
formed by continuously applying an integral bead of adhesive
extending from the underside of any given tile, around the leading
edge of the given tile and on the outside surface of the given
tile.
[0020] In accordance with yet another embodiment of the invention,
any given tile in the second and subsequent courses is initially
laid so that its trailing edge overlies a lower tile with a portion
of its trailing edge in contact with the U-shape adhesive pattern
of the lower tile and the U-shape pattern for the given tile is
then formed by continuously dispensing an integral bead of adhesive
from the underside of the given tile, around the leading edge of
the given tile and onto the outside surface of the tile or from the
outside surface of the given tile about the leading edge of the
given tile to the space between the underside of the given tile and
the roof Preferably, the leading edge of the given tile is lifted
when the bottom leg of the adhesive U-shape sandwich pattern is
dispensed.
[0021] In accordance with another embodiment, the integral,
continuous U-shaped pattern is formed on any given tile for the
second and subsequent tile courses in two steps by first dispensing
a bead of adhesive comprising the bottom leg of the pattern onto
the roof (or alternatively, on the tile underside) and dispensing,
in a second step, a second bead onto the outer surface of the given
tile, after the given tile has been laid over a lower tile so that
its leading edge is in contact with the bottom leg adhesive
deposit. Significantly, the second bead is dispensed past and
beyond the leading edge of the given tile to insure formation of
the bight portion of the U-shaped pattern before tack free or open
time of the foam formulation has elapsed whereby the top, bottom
and bight portions of the pattern are formed in an integral unitary
pattern without visible knit lines and completely extending between
tile and roof areas in sealing contact therewith.
[0022] In accordance with another aspect of the invention, a method
for installing roof tiles onto a roof is provided. The roof tiles
having opposing trailing and leading edges intersecting opposing
side edges and underside and outside surfaces. The method includes
the acts of a) dispensing a one-component, polyurethane froth in a
U-shape pattern extending from the underside of any given tile
around the leading edge of the given tile to the outside of the
given tile and b) placing a tile in overlapping relationship to a
lower tile whereby the adhesive on the underside of the given tile
contacts the roof adjacent the leading edge of the given tile while
the underside of the given tile adjacent the trailing edge contacts
the adhesive pattern dispensed on a lower tile to establish sealing
contact between the underside of a given tile adjacent its trailing
edge with the outside of the lower tile and between the underside
of the given tile adjacent its leading edge with the roof.
[0023] In accordance with another aspect of the invention, an
improvement is provided for a roof having a substrate, an
underlayment covering the substrate and a plurality of roof tiles
adhesively affixed to the substrate. The improvement comprises each
roof tile being affixed to the roof by a one-component adhesive
applied to individual roof tiles of the plurality of roof tiles in
a U-shape, continuous sandwich pattern, one pattern for each roof
tile. The pattern includes a bottom leg adhesive deposit between
the underside of any given roof tile and a roof substrate, a top
leg adhesive deposit between the outside of the given tile and the
underside of any overlying tile and a connecting bight adhesive
deposit extending beyond the leading edge of the given tile and
vertically extending between the underside of the overlying tile
and the roof substrate.
[0024] It is a general object of the invention to provide a system,
method and apparatus, for applying one-component adhesive,
particularly a one-component polyurethane froth or foam, to secure
roof tiles to a roof.
[0025] It is another object of the invention to provide a roof
construction system for adhering roof tiles to a roof, particularly
roofs for residential dwellings, which is an improvement over
existing methods.
[0026] It is a particularly important object of the invention to
provide a roof construction for adhesively securing roof tiles to a
roof which has any one or more or any combination of the following
features:
[0027] a) only one adhesive pattern per tile is required;
[0028] b) the adhesive pattern provides improved strength
properties over other known methods of adhesive placement;
[0029] c) the adhesive pattern provides direct sealing contact from
the tile to the roof at two different areas for each tile;
[0030] d) the adhesive deposit pattern uses a minimum amount of
adhesive to cover any given roof;
[0031] e) the adhesive pattern, by its unitary, relatively large
structure, is believed able to better distribute stresses
attributed to differential thermal expansions between roof and
tile;
[0032] f) the adhesive pattern system is easy or simple to
apply;
[0033] g) the adhesive deposit system provides sufficient air
flow/drainage between the tiles satisfactory to at least meet any
known building code requirements; and/or,
[0034] h) the adhesive deposit system allows for quick installation
of the roof reducing overall roofing cost.
[0035] Another object of the invention is to provide a method for
applying roof tiles to a roof which, while using no more adhesive
than that of prior art two adhesive pad placement systems, produces
not only a stronger, individual tile bond but also bonds both
overlied and overlaid tiles to the roof in an interlocking adhesive
pattern to increase the effectiveness of the adhesive bond for the
entire roof.
[0036] These and other objects of the invention will become
apparent to those skilled in the art upon reading and understanding
the Detailed Description of the Invention set forth below taken in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The invention may take form in certain parts and in an
arrangement of certain parts taken together and in conjunction with
the attached drawings which form a part of the invention using like
reference numerals to refer to like parts and wherein:
[0038] FIG. 1 illustrates a typical pitched roof upon which roof
tiles are attached;
[0039] FIG. 2 is a perspective view of a segment of a prior art
roof construction utilizing a two-component adhesive foam to adhere
a roof tile course to a roof substrate using continuous, linear
beads of adhesive foam extending along the entire length of the
roof tiles and represents the system described in the '342
patent;
[0040] FIG. 2A is a cross-sectional view of the system shown in
FIG. 2 with the tiles having an anchor lug;
[0041] FIG. 3 is a perspective view of a segment of a prior art
roof construction utilizing an opposing comer one-component foam
deposit representative of the system disclosed in the '536
patent;
[0042] FIG. 3A is a cross-sectioned view of the prior art based on
a variation of the roof construction shown in FIG. 3 with the
adhesive shown displaced from its dispensed position.
[0043] FIG. 4 is a perspective view of a section of a roof
illustrated by a placement of three courses of flat roof tiles
installed thereon using the present invention;
[0044] FIG. 5 is a perspective view similar to FIG. 4 illustrating
an alternative embodiment of the invention as applied to flat roof
tiles;
[0045] FIG. 5A is a cross-sectional view of the flat tile
application shown in FIGS. 4 or 5;
[0046] FIG. 6 is a view similar to FIG. 4 but showing the system of
the present invention applied with high profile, non-planar roof
tiles;
[0047] FIG. 6A is a cross-sectional view of the high profile tiles
shown in FIG. 6;
[0048] FIG. 7 is a view of a roof section similar to FIG. 3 for
showing the system of the present invention applied to a medium/low
profile roof tile;
[0049] FIG. 7A is a cross-sectional view of the medium/low profile
tile shown in FIG. 7;
[0050] FIGS. 8, 8A and 8B are planar views showing one way of how
the adhesive sandwiched pattern is developed during placement of
the tiles;
[0051] FIG. 9 is another view showing how the sandwiched pattern
can be applied to a roof tile;
[0052] FIGS. 10 and 10A are cross-sectioned step views showing
another way to form the inventive sandwich pattern;
[0053] FIGS. 11 and 11A are perspective views showing different
shapes of an adhesive deposit making up a portion of the adhesive
pattern used in the present invention; and,
[0054] FIGS. 12 and 12A are schematic representations of a tile
test.
DETAILED DESCRIPTION OF THE INVENTION
[0055] Referring now to the drawings wherein the showings are for
the purpose of illustrating a preferred embodiment of the invention
only and not for the purpose of limiting the same, there is shown
in FIG. 1 a dwelling 10 having a roof 12 disposed thereon at a
particular angle or pitch designated by the letter "P" in FIG. 1.
Roof 12 is formed by a plurality of structural members or joists 13
which are longitudinally spaced from one another and extend
vertically upward from a lowest most edge or eave 14 of the roof at
pitch "P" to a central ridge beam 16 at the roof apex 17 in a
conventional manner.
[0056] Joists 13 support a roof substrate 20 which covers the roof.
Roof substrate 20 is commonly formed of a multiple layer
construction and typically includes a sheeting 21 or decking which
may comprise plywood, particle board, cement boards, or the like
and which are nailed or otherwise mechanically fastened to joists
13. Over sheeting 21 is an underlayment 22 or final covering or cap
sheet which is typically a water resistant material such as roofing
felt or tar paper. Underlayment 22 is typically fastened by
mechanical connections to sheeting 21 and joists 13. Roof tiles are
directly secured to underlayment 22 except if the pitch of the roof
is steep, i.e., over a 7:12 pitch. In such instance, batten strips,
shown in phantom in FIG. 1 and designated by reference numeral 24,
which are vertically spaced and extend longitudinally along roof 12
are provided. When batten strips are used, the roof tiles are
provided with anchor lugs on the underside of the tiles. The anchor
lugs slip over and engage the upper edge surface of a batten strip
24. For convenience, "roof" as used herein and in the claims
includes joist 13, sheeting 21, underlayment 22 and batten strips
24 if applicable and includes any construction extending over the
walls of a building or dwelling to which roof tiles are secured.
"Substrate" as used herein and in the claims and for convenience
only means any arrangement of coverings or the like fixed to the
joist 13 onto which the roof tiles are attached.
[0057] Referring now to FIG. 2 there is shown a prior art roof
construction which is typical of the construction described in U.S.
Pat. No. 5,362,342. As described in the '342 patent and as shown in
FIG. 2, the construction includes a plurality of medium/low profile
roofing tiles 30. (Tile 30 shown in FIG. 2 has traditionally been
referred to as a low profile tile and more recently as a medium
profile tile. For consistency in terminology, it will be
subsequently referred to herein and in the claims as a low profile
tile.) Low profile tile 30 is generally rectangular (as are all the
tiles) having opposing leading and trailing edges 31, 32
intersecting with opposing side edges 34, 35. (Leading edge 31 is
commonly referred to as the "head" of the tile while trailing edge
is commonly referred to as the "nose" or "tail" of the tile.
"Leading" and "trailing" will be used throughout the Detailed
Description and in the claims and when used with "edge" designate
the edge surfaces as shown in the drawings.) Side edges 34, 35
designate the edge surfaces as shown in the drawings and have
interlocking grooves adjacent thereto as shown or, depending on
tile configuration, as a part thereof. In addition, low profile
tile 30 has a non-planar outside surface 36 and a similarly formed
non-planar underside surface 37. Non-planar surfaces 36, 37 are
formed as a hollow central semi-circular portion 39 flanked by two
hollow quarter portions 40, 41. The intersection of semi-circular
portion 39 with one quarter portion 40 forms generally a flat
contact underside rib 43 (i.e., tile pan section) while the
intersection of semi-circular portion 39 and the other quarter
portion 41 forms a second underside rib 44 (i.e., a tile pan). As
shown in FIG. 2, underside ribs 43, 44 are positioned closely
adjacent underlayment 22 of roof substrate 20. In accordance with
the teachings of the '342 patent, a bead 46 of a two-component
polyurethane foam is placed on underlayment 22 extending from
leading edge 31 to trailing edge 32 to establish sealing contact
between roof 12 and at least one of the underside ribs 43, 44. When
roof tiles 30 are placed on foam bead 36 they are spaced from
underlayment 22 by the bead to insure an air space between tile and
roof. (A similar air space is formed by the pad of mortar typically
used in conventional applications.) Bead 46 uses a fairly
significant amount of polyurethane foam.
[0058] This is perhaps best illustrated by referring to a
cross-sectional representation of a low profile roof tile 30 fitted
with an anchor lug 48 as best shown in FIG. 2A. The effect of
batten strip 24 is to vertically displace low profile tile 30 from
underlayment 22 a distance at least equal to the height of batten
strip 24. The two-component bead 46 must extend the distance
represented by dimensions "A" at the trailing edge to the dimension
"B" at the leading edge 31 of low profile tile 30. This can be in
excess of 2" for conventional tiles having a length between leading
and trailing edges 31, 32 of about 16". At the same time, it is to
be recognized that anchor lug 48 and batten strip 24 take up space
otherwise occupied by foam.
[0059] While a significant amount of adhesive is thus used, a more
subtle point relates to the expansion of the foam. As noted in the
Background, when a two-component foam is employed, the reaction of
the two-components, as they are mixed together, produces the foam.
Assuming that the dispensing gun mixes the components at the proper
formulated ratio, the chemical will immediately expand within
seconds after striking the roof. That is, a two-component foam will
typically spray as a liquid onto underlayment 22 and within seconds
bead up as a foam. The discussion of "expansion" herein refers to
the continued growth of the foam after it has initially formed
itself into a foam. As is well known, not all the isocyanate has
reacted after the foam is formed. The reaction of the free
isocyanate produces closed cells which result in continued
expansion of the foam. The reaction continues not only during the
open time or tack free time but also after a skin has formed at
which time the foam is no longer capable of being used as an
adhesive. Curing to a hardened state continues for some time after
skinning and although some free isocyanate may react with moisture,
the foam does not materially expand further. Thus, to some extent,
a two-component foam is somewhat suited for the excessive foam
application as shown in FIGS. 2 and 2A since low profile tiles 30
will not significantly move as the two-component foam cures to its
hardened state. The "down side" to the two-component foam is that
the tack free time or open time for a two-component foam is
relatively short so that only a set number of tiles can be laid
before the foam skins. In contrast, one-component foams use
moisture from the air and the substrate to cause chemical reaction
with the isocyanate.
[0060] A one-component foam will quickly expand to a froth or foam
when exposed to atmosphere. In fact, the preferred one-component
foam used in the invention is dispensed as a froth as it leaves the
gun similar to how shaving cream is dispensed from an aerosol
container. In contrast to typical two-component foams, typical
one-component foams will likely expand more after the one-component
urethane froths until the foam cures. While the expansion, as a
percentage, is not significant, when a one-component foam was used
in an excessive foam application such as disclosed in the '342
patent, the tiles could be lifted after they were laid. It is
possible that if a one-component foam was used for the pattern
disclosed in the '342 patent, that there could be varying
expansions of the foam as it cured resulting in uneven tile
displacement. If the tiles are displaced unevenly, the adhesive is
unacceptable. On the other hand, the tack free or open time for a
one-component foam is generally accepted as being longer than a
two-component foam. Again, this discussion is predicated on
generally accepted formulations of two-component and one-component
foams. Special formulations can be had which vary the expansion
characteristics of the foam, the adhesive characteristics of the
foam, and the tack free time or open time of the foam whether the
formulation relates to a one-component or to a two-component
foam.
[0061] Referring now to FIG. 3 there is shown a prior art roof
construction which is typical of the construction illustrated in my
'536 patent. The roof construction is illustrated for a flat tile
50 which, like low profile tile 30, has leading and trailing edges
31, 32, respectively which intersect with opposing side edges 34,
35. The tile shape adjacent side edges 34, 35 is grooved as shown
to provide an interlocking engagement with adjacent tiles. Flat
tile 50 has a planar outside surface 51 and a generally planar
underside surface 52. Typically, underside surface 52 comprises a
series of longitudinally extending ridges or ribs forming grooves
therebetween (not shown) except for flat clay tiles which are
smooth.
[0062] In the roof construction described in my '536 patent, a
leading edge deposit of foam in the form of a leading edge pad or
paddy 54 is deposited between roof underlayment 22 and underside
surface 52 of any given flat tile 50. Specifically, leading edge
paddy 54 is placed at a corner formed between leading edge 31 and
one of the side margins 34 or 35. A second foam deposit in the form
of a trailing edge pad or paddy 55 is placed between underside
surface 52 of any given tile and outside surface 51 of an adjacent
lower tile. Trailing edge paddy 55 is placed adjacent trailing edge
32 and an opposing side margin 34 or 35 but at the opposing corner
to that occupied by leading edge paddy 54, so that leading edge
paddy 54 and trailing edge paddy 55 lie on a diagonal. This is
specifically shown in FIG. 3, by the leading edge paddy designated
54A provided for flat tile 50A. Paddy 54A extends between roof and
tile 50A. A trailing edge paddy 55A is shown for roof tile 50A and
the corner-to-corner diagonal is indicated by dot-dash line 56.
Paddy 54A extends between tiles 50A and 50B. Tiles 50 are laid in
longitudinally extending roof tile courses and the arrangement
illustrated in FIG. 3 includes the lowermost or first roof tile
course which overlies roof eave 14 and necessitates additional foam
paddies 58 adjacent but spaced from trailing edge 32 of the first
course tiles. Additionally, because of the cave overhang of the
first course tiles, trailing edge paddy 55 has to be likewise
spaced from trailing edge 32 of the tiles in the first roof course.
Tiles in the second and subsequent courses (and until the last
course at ridge beam 16) are laid so that the tiles trailing edge
32 always overlaps the underlying immediately lower tiles leading
edge 31 to define an overlap designated by the dimension shown as
"D" in FIG. 3. Paddies 54, 55 are sized to a dispensed area fitting
within this overlap distance "D".
[0063] The roof construction of my '536 patent reduces the volume
of polyurethane foam used to adhere the roof tiles to roof 12. A
more subtle but critical result is that use of less foam results in
the weight of the tile allowing the paddy to expand during cure
without raising the roof tile. Simply put, less foam reduces the
foam expansion force so that the weight of the tile can force the
foam to expand or move into any free space under the tile without
lifting the tile. It should be noted that in the roof construction
shown for my prior art '536 patent, the tile is secured to roof 12
only by leading edge paddy 54. Trailing edge paddy 55 is adhesive
connecting one tile to another. A wind force directed against the
tile such as shown by reference numeral 59 in FIG. 3 is resisted by
only one paddy. That is, the two paddies together provide an
adhesive connection from the roof to the tile to an overlying tile
and that connection is, as shown in FIG. 3, separated from each
other. Thus, the strength of the bond is limited. This invention
uses an entirely different placement pattern to produce a stronger
bond with a one-component foam that does not adversely affect tile
placement because of expansion of the foam.
[0064] My '536 patent discloses that the paddies are placed in
opposite corners at the undersides of the roof tile. When the tiles
are installed onto the roof, and whether or not the tile courses
are offset relative to one another, the paddies do not overly one
another. Despite the teaching of the '536 patent to locate the
paddies in opposite tile corners, roof installations have been
observed where the paddies are located more towards the center of
the tile so that the pad of one tile overlies the pad or at least a
portion of the pad of an underlying tile when the overlying tile is
pressed down into the lower tile. In most tiles, there is an anchor
lug or ridges formed on the underside of the tile which directs or
receives the adhesive displaced from the adhesive pad when the tile
is pushed towards the roof to seat the tile. However, flat clay
tiles traditionally have a flat smooth surface. When the tile is
seated the vertical space between tile underside 37 and roof 12
near tile leading edge 31 and the vertical space between tile
underside 37 and outside surface 36 of the overlaid tile near tile
trailing edge 32 is reduced. I believe that for flat clay tiles,
the foam in pads 54, 55 moves outwardly in all directions and pads
54, 55 increase in size. In my '536 patent pad shapes within the
specified gram size limitations comprise a rectangular pad
2".times.3" by 1" high and a circular foam of about 21/2" by 1"
high diameter. The areas covered by these pads, as dispensed, are 6
in.sup.2 for the rectangular pad and about 5 in.sup.2 for the
circular pad. The pad heights are typically reduced from 1" to
about 1/2" when the tiles are pushed into their laid set condition.
The pads will typically expand in coverage to about 10 in.sup.2.
Thus, the diameter of the circular pad will increase to slightly
over 31/2"and the rectangular pad will increase to about
25/8".times.3{fraction (7/8)}". The overlap "D" varies by
manufacturer but is generally about 3". (Overlap "D" varies by tile
type and code, typically from a minimum of about 2" to a maximum of
about 4". Tile sizes vary significantly. Nominally, tiles have a
width of about 9-10" and a length of about 14-18". However, these
ranges could be significantly expanded both at the high end and the
low end. European tiles are significantly smaller. Certain cement
tiles are significantly larger.) The rectangular pad in its
flattened state will generally stay within the overlap. A portion
of the circumference of the round pad will extend beyond the
leading edge 31 of the overlaid tile. This is illustrated in FIG.
3A where dash lines 49 indicate the general position occupied by
pads 54, 55 when dispensed. The pads are drawn in their flattened,
displaced condition and when they are applied, not at the corners,
but at the center portions of the tile. A circumferential portion
of each pad 54, 55 extends beyond the leading edge 31 of the
overlaid tile but the foam does not extend between the pads. Unless
the pad size is significantly increased, foam extending past
leading edge 31 does not establish contact between roof 12 and
underside surface 37 of the overlying tile. Further, even if the
pads were significantly oversized, and misplaced to somehow
establish contact, the tiles are normally laid in a course
progression. The tack free time of leading edge pad 54 may have
lapsed when the overlying tile is placed over a tile establishing
visible knit lines (non-adhesion between the two foams) between the
foam of the two oversized pads.
[0065] It should also be noted that I have often observed tile
applications with mortar. In those applications where the mortar
pad is sometimes haphazardly placed towards the upper center of the
tile, the mortar can also be displaced beyond leading edge 31 when
the tile is pressed down into the mortar. However, bonding by the
mortar between the higher tile and roof is not believed to occur
significantly. In a mortar application, there is also no bonding
between the tiles. Mortar is usually not placed between tiles
except to seal the exposed edges at the ends of the tile courses,
i.e., rake.
[0066] My observations of how I believe the foam and mortar is
being displaced when a flat tile is pushed into the roof to set the
tile in place, is utilized, in part, to form one of the
underpinnings of my present invention.
[0067] Referring now to FIGS. 4, 5 and 5A, there is shown the roof
construction of the present invention applied to flat tiles 50. The
roofing construction includes a U-shaped pattern 60 of polyurethane
adhesive purposely dispensed as a "U" form extending about leading
edge 31 of a tile such that when the tiles are placed in position,
the U-shaped pattern 60 is sandwiched between roof, tile and
overlying tile. U-shaped pattern 60 comprises a top leg deposit 62,
a bottom leg deposit 63 and a bight deposit 64 interconnecting top
and bottom leg deposit 62, 63 into a unitary, integral pattern.
When the tiles are pushed into position U-shaped pattern 60
increases in areas to establish sealing contact and adherence of
the tiles to the roof when the polyurethane cures. Significantly
bight deposit 64 may dimensionally increase more than top and
bottom deposits 62, 63 since bight deposit 64 may receive adhesive
therefrom as described with reference to the prior art. This
assures that bonding occurs between the underside surface of the
overlying tile and the roof.
[0068] While in accordance with the broader aspects of the
invention, U-shaped pattern 60 could comprise any number of
adhesive compositions (including a two-component polyurethane
foam), it is a specific inventive feature of the construction to
form a unitary, contiguous U-shaped pattern with a one-component
polyurethane and specifically a one-component polyurethane froth.
In the preferred embodiment, the adhesive pattern is formed from
assignee's one-component polyurethane froth sold under the brand
name Handi-Stick.RTM. Roof Tile Adhesive. However, a number of
one-component polyurethane foams can be used. For example, a foam
sold under the brand name Tile Bond.RTM. manufactured by Insta-Foam
Products, Inc. may be used. The preferred one-component
polyurethane foam or froth used in the present invention is
classified as a low density, (typically closed cell) adhesive foam
having minimum expansion characteristics. Some specific discussion
of typical characteristics of one-component and two-component foams
will be helpful in understanding the present invention. A high
density foam is typically understood as a foam that has a density
greater than 4 lbs/ft.sup.2 when it is dispensed as a foam in a
free, unrestrained state. In the present invention a one-component,
low density foam having a density in the range of anywhere from 0.8
to 4.0 lbs/ft.sup.2 and preferably in the range of 1.1 to 2.5
lbs/ft.sup.2 is used. When a tile is pressed down, the foam in
U-shaped pattern 60 (during the open time) will laterally displace
itself to an open area (i.e., squish) although at some discrete pin
head area, it may be restrained and increase in density at that
area perhaps 1 lb/ft.sup.2. Overall, the density of the foam will
not increase when the tile is pressed down. U-shaped pattern 60 has
a weight of anywhere from about 9 to 15 grams and preferably from
12-14 grams. This weight is believed about equal to that used in
the 2 paddy prior art system disclosed in the '536 patent.
Alternatively stated the surface area of a roof tile is about 1.2
sq. ft. and after the tiles have been assembled in overlying
position and pushed down into the foam, the surface area of the
tile occupied by U-shaped pattern is about 9 to 12 in.sup.2 and
preferably about 10 in.sup.2. U-shaped pattern 60 when dispensed as
a continuous bead and before being pressed by the tile occupies a
tile (to roof) area of about 6 in.sup.2. The density of the foam
has application to the system not only as a measure of how much
foam is used to secure the roof tile to the roof but also as to the
vertical spacing between the tile and roof. Obviously, a high
density foam will not displace under the weight of the tile to the
extent of a low density foam and will not give the same surface
area contact.
[0069] However, the expansion of a one-component foam, after it has
been initially dispensed to assume its free standing state
continues to expand as the free isocyanate continues to react with
moisture until the foam is completely cured. The expansion of the
one-component foam after the foam has been dispensed and assumes
its free standing state (almost immediately but not more than 2 - 3
seconds after dispensing) is no more than 50% and preferably no
more than about 20% of its free standing volume. In summary, a
preferred low density foam (as defined) dispensed in the pattern
(as defined) and having desired expansion characteristics (as
defined) will provide desired tile to roof spacing having desired
bond strength without causing tiles to become uneven after the foam
has cured.
[0070] While the inventive system could be applied if the adhesive
is a two-component polyurethane foam, there are further advantages
to a one-component foam relating to the application of the system
of the present invention. Because a one-component foam is moisture
cured, the roofing application can start in early morning when dew
or moisture is on the roof. The installer does not have to wait
until the moisture is evaporated as in a two-component application.
The open time or tack free time for a one-component application is
significantly longer than for a two-component application. The open
time for the Handi-Stick, one-component adhesive is about 4-5
minutes while the open time for a two-component foam is about 30 to
45 seconds. (These time, of course, assume "normal" or "ambient"
temperatures and humidity.) As will be noted, Handi-Stick is
dispensed as a froth which makes it desirable, (not however
necessary) to continuously dispense U-shaped pattern 60 as an
integral, unitary pattern whereas other one-component foams may
bead only after impact with an object. (To avoid confusion in
terminology, "foam" when used herein includes froth as well as foam
whether produced by one-component or two-component polyurethane
adhesives. "Froth" means froth--a foam formed as it leaves the
nozzle in distinction to chemical reactions forming a foam after
the chemicals leave the gun such as when they strike the roof or
tile.) The cure time or the time to bond the tile to the roof for a
one-component foam is about 2 to 4 hours while the cure time for a
two-component foam is typically 1/2 to 1 hour. The time of course
to "chemically" cure the foam is typically considered to be 24 to
48 hours although, technically, the time to completely react all
the isocyanate may continue for a much longer time. However, it is
believed desirable for roofing applications to have the longer tack
free time before skinning of the one-component foam occurs so that
U-shaped pattern 60 can be formed as an integral structure. While
the longer cure time for a one-component foam may be viewed,
initially as a detriment, in practice there is no detriment because
the roof is laid from eave upward so the installer is not walking
on the tiles after they have been laid.
[0071] As best shown in FIG. 5A, when tiles 50 are positioned onto
roof substrate 20, U-shaped pattern 60 becomes sandwiched between
tiles and the roof. Specifically, top leg deposit 62 is in sealing
contact with outside surface 51 of a lower tile 50B and the
underside surface 52 of an immediately adjacent higher tile 50A.
The sealing contact extends substantially the distance of overlap D
from leading edge 31 towards trailing edge 32 of lower tile 50B.
Bottom leg deposit 63 is in sealing contact with roof substrate 20
and the underside 52 of lower tile 50B from leading edge 31 towards
trailing edge 32. If the adhesive deposit stopped here, there could
be some resemblance to the FIG. 3 prior art in that top leg deposit
62 contacts two adjacent tiles similar to prior art trailing edge
paddy 55 and bottom leg deposit 63 contacts tile and roof similar
to prior art leading edge paddy 54 except that leg deposits 62, 63
overlie one another (and by definition extend a slightly longer
distance in that they begin from leading edge 31 and are not
proximate to the leading edge). Significantly, bight deposit 64 is
in sealing contact with roof substrate 20 and underside surface 52
of higher tile 50A. This is an additional roof contact extending
from and wrapping about leading edge 31 not present in the prior
art and contiguous with top and bottom leg deposits 62, 63. Also,
significantly, bight deposit 63 is tying the tile-to-tile sealing
contact into the roof-to-tile sealing contact increasing the
overall strength of the bond. That is, U-shaped adhesive pattern 60
is bonding underside surfaces 51 of both tiles 50A, 50B to roof 12
while also tying the two tiles together. Generally speaking, top
and bottom deposits 62, 63 overlie one another, but in application,
they may be slightly skewed depending on how the froth is
dispensed. It is preferred that bottom leg deposit 63 extend
longitudinally further towards trailing edge 32 than top leg
deposit 62 although the invention will function with equal length
leg deposits. Preferably, leg deposits 62,63 are in the form of an
elongated rectangular bead, or alternatively, can be in the form of
an oval bead as shown in FIGS. 11 and 11A. FIG. 11 shows top leg
deposit 63, preferably having a width dimension "W" of about 4" to
41/2" (extending between opposing side edges 34, 35), a length
dimension "L" of about 11/2" to 13/4" (extending from leading to
trailing edges 31, 32) and a height dimension "H" shown in FIG. 11A
of about 1" to 11/4. Preferably, the "W" dimension of bottom leg
deposit 64 will be 1 to 1.25 times the "W" dimension of top leg
deposit 63 to provide increased resistance to wind lift. Bight
deposit 64 will have the same width as top deposit 62 (or bottom
deposit 63) and a height equal to twice the height "H" of top
deposit 62 (or bottom deposit 63) plus the thickness of the tile.
The length of bight deposit 64 will be at least equal to the height
of top deposit 62 (or bottom deposit 63). Top and bottom leg
deposits 62, 63 can be formed elliptical as shown in FIG. 11A
(width of about 31/2and length of about 21/2) provided that the
width edge of the ellipse completely extends to leading edge 31 so
that bight portion can be formed throughout the length of the
ellipse. All dimensions are given in dispensed form. Other
dispensed shapes may be used.
[0072] When the tiles are placed onto the dispensed froth, before
the froth reaches its tack condition, the low density foam will be
reduced to about 3/4 its height. The froth will spread to other
areas including spreading into bight portion 64 from top and bottom
deposits 62, 63. However, froth dispensed in bight portion 64 will
always spread increasing bight portion 64 size and bonding area
when the tile is initially positioned. When the tile is pushed
towards the roof to establish the final tile position further
dispensing the foam will result typically reducing its height to
about 1/2 of its dispensed height. The bond in all instances is
unitary.
[0073] Again, what the U-shaped pattern is accomplishing with a
minimal usage of foam, is to provide (when compared to my prior
invention) an increased roof-to-tile contact area while directly
tying the overlaying and the overlaid tiles into the roof as well
as tying the tiles together. Additionally, because of the
relatively large area contact of U-shaped adhesive pattern 60 in a
unitary structure, it is believed that the adhesive will be better
able to distribute the stresses resulting from differential
temperature expansion between roof tiles and roof substrate.
[0074] Referring still to FIGS. 4 and 5, there is shown a portion
of tile coverage including a portion of a first or lower most tile
course 70, a portion of a second tile course 71 overlying first
tile course 70 and a portion of a third tile course 72 overlying
second tile course 71. In FIG. 4, the tiles in each tile course are
longitudinally shifted a distance approximately equal to 1/2 the
distance between tile side edges 34, 35 relative to the tile
positions of the immediately adjacent upper and lower tile courses.
For flat tiles 50, this pattern of laying the tiles is generally
recommended by the tile manufacturers. In the tile offset pattern
position illustrated in FIG. 4, U-shaped adhesive pattern 60 may be
optionally placed about the mid-point of leading edge 31. In this
arrangement, it is possible by using only one U-shaped pattern 60
per tile to establish for each separate tile a three position
sealing contact with roof 12. For example, flat tile designated 50C
has contact with the roof by adhesive pattern designated 60A as
described above. In addition, contact with the roof is also
established by adhesive patterns designated as reference numerals
60B and 60C. Three tile to roof adhesions or bonds are thus
made.
[0075] However, it must be clear that the invention is not
necessarily limited to a particular placement of U-shaped adhesive
pattern 60 in a specific position about leading edge 31 of any
given tile. In fact, U-shaped adhesive pattern 60 can be placed
anywhere along and about leading edge 31 and several different
positions are illustrated in FIG. 5. Improved bonding will occur no
matter where the U-shaped pattern is dispensed along leading edge
31. In FIG. 5, tiles 50 are not offset and tile courses 70, 71, 21
are vertically aligned with one another as shown. U-shaped adhesive
pattern 60 can be placed at various positions along and about
leading edge 31 as shown by dot-dash centerlines designated by
reference numerals 74,75 and 76 extending between U-shaped adhesive
patterns of upper and lower tiles. It should also be noted that for
the first or eave tile course 70, two lower pads of adhesive 78 are
placed adjacent to but spaced from trailing edge 32 of tiles 50 in
first tile course 70. Two pad deposits 78 are preferred.
[0076] Referring now to FIGS. 6 and 6A there is shown an
application of U-shaped adhesive pattern 60 of the present
invention to a high profile tile 80. High profile tiles have a
non-planar outside surface 81 and a non-planar underside surface 82
which in cross-section somewhat assumes a "S" configuration as
shown for diagrammatic purposes but in practice is more in the
shape of a flat converted to a semi-circular or barrel portion. The
portion of the "S" which contacts underlayment 22 is referred to as
a pan section 84 of high profile tile 80. U-shaped adhesive pattern
60 must be placed in the pan section. Further, most high profile
tiles 80 are provided with an anchor lug 85 in its pan section
adjacent leading edge 31. Typically, anchor lug 85 for high profile
tile 80 has a depth of about 5/8" to 3/4" and batten strips 24 are
5/8" thick. Adhesive pattern 60 as shown somewhat by adhesive
pattern 60D in FIG. 6, and more particularly, by bottom leg
deposits 63 in FIG. 6A, extend about and around anchor lug 85 and
batten strip 24 (if used). Further, high profile tiles 80 are laid
in tile courses which are not longitudinally offset and resemble
the pattern disclosed in FIG. 5. Thus, adhesive deposits 60 as
shown in FIG. 6 are positioned in alignment with vertically
extending centerlines designated by reference numeral 87 which
align with side edges 34, 35. U-shaped adhesive pattern 60
comprises the same bead deposits and functions in the same manner
for high profile tile 80 as it does for flat tile 50 as explained
with reference to FIGS. 4, 5 and 5A.
[0077] Referring now to FIGS. 7 and 7A, the roofing construction of
the present invention is applied to low profile tiles 30. Low
profile tiles 30 are typically provided with an anchor lug 88, best
shown in FIG. 7A, at each underside rib or pan section 43, 44
adjacent leading edge 31 and typically having a depth of about
1/2". As with high profile tile 80, adhesive U-shaped pattern 60
must be applied to each low profile tile 30 at one of its underside
rib or pan sections 43,44 (conceptually adhesive pattern could be
applied to both) and about leading edge 31. U-shaped adhesive
pattern 60 can be applied in a pattern where U-shaped adhesive
deposits formed on higher and lower tiles are vertically aligned
with one another such as shown by centerline 90 in FIG. 7 or are
vertically offset to extend on a diagonal such as shown by
centerline 91 in FIG. 7.
[0078] There are several ways in which adhesive pattern 60 can be
dispensed in the desired sandwiched configuration. Perhaps the
simplest way to dispense U-shaped adhesive pattern 60 is
diagrammatically illustrated in FIG. 9. In FIG. 9, a dispensing
nozzle 95 of a gun (or valve of a pressurized container)
continuously dispenses a foam bead from the tile's outside surface
36, 51 or 81 to the tile's underside surface 37, 52, or 82 or from
the underside to the outside of the tile. This method of forming
the adhesive is particularly applicable for use with assignee's one
component Handi-Stick adhesive which produces a froth immediately
upon expelling the adhesive from the gun nozzle. Thus, a froth
having a shaving lather consistency is dispensed from the gun
nozzle. It can therefore be applied by resting the tile on its
trailing edge 32 and dispensing a bead about leading edge 31, after
which the tile is simply positioned in place. This type of
application could not be easily accomplished with a two component
adhesive.
[0079] A more systemic approach is illustrated in FIGS. 8, 8A and
8B. In FIG. 8, bottom leg deposit 63 is laid on underlayment 22
extending a desired distance from a tile chalk line 96 (and
extending beyond the chalk line to start forming bight portion 64).
Alternatively, bottom leg deposit 63 can simply be applied as a
bead to the underside of the tile. In FIG. 8A, a tile, for example
flat tile 50C, is laid in position relative to chalk line 96 so
that it overlies a lower tile shown as 50A. When tile 50C is laid
on underlayment 22, bottom leg deposit 63 spreads out as it
flattens and extends past chalk line 96. In FIG. 8B, a second bead
is now dispensed on outside surface 51 of tile 50C. The slight
portion of bottom leg deposit 63 extending beyond chalk line 96
serves as a guide to insure that the top bead overlies bottom leg
deposit 63. This bead of adhesive as it is deposited, forms top leg
deposit 62. Importantly, the froth deposit application continues
past chalk line 96 to form contiguous bight deposit 64. Because a
one-component foam is used and the U-shaped pattern 60 is formed
well within the open time period, the foam continuing to be
dispensed after the top bead is formed is able to flow into, meld
and fuse with bottom leg deposit 63 and without forming any knit
lines (at least knit lines which are visible to the eye) between
them thus producing an integral U-shaped structure when the next
tile is placed in overlying relationship to tile 50 A. U-shaped
pattern 50 will further flatten in its dispensed top and bottom leg
portions 62, 63 and its bight portion 64 as tile 50 A is pushed
downward into its laid position.
[0080] Still another way to form U-shaped adhesive pattern 60 is
disclosed in FIGS. 10 and 10A. In FIG. 10, a tile, for example flat
tile 50A, is placed in its vertical overlying position over lower
tile 50C which has its U-shaped adhesive deposit 60 formed
thereabout as shown. Leading edge 31 of tile 50A is lifted up and
the user inserts dispenser nozzle 95 to dispense bottom leg deposit
63. Tile 50A is then released and the dispensing nozzle 95
continues to dispense a froth bead forming bight deposit 64 and top
leg deposit 62. When the tile is equipped with an anchor lug it is
possible to modify the application illustrated in FIG. 10 in that
the dispensing nozzle can simply dispense the foam bead behind and
on the side of and in front of the anchor lug without lifting the
tile. In either instance, after U-shaped adhesive pattern 60 has
been formed as shown in FIG. 10A, the tile is then placed firmly
down into contact with U-shaped adhesive 60 at its trailing edge.
As will be noted, the tiles will be laid in vertical progression
from lowest to highest and not necessarily longitudinally in tile
course. If the installer lays several tile courses, the U-shaped
pattern is not to be applied until the overlying tile is ready for
positioning. Removable shim blocks may be inserted.
[0081] Tests have been conducted which demonstrate that the roofing
construction of the present invention has increased bonding
strength when compared to my prior invention disclosed in the '536
patent. The present invention and my prior invention use
approximately similar amounts of one-component foam when covering a
roof.
[0082] A test was conducted to obtain some evaluation of the
bonding characteristics of the present invention when compared to
the paddy placement of my prior invention disclosed as prior art in
FIG. 3. This test was not the type of test described in my '536
patent. Particularly, the overlying tile pattern in which U-shaped
adhesive pattern 60 would produce a number of bond benefits as
described above was not replicated. Instead, U-shaped adhesive
pattern 60 was simply formed about leading edge 31 of the tile and
the tile pulled from the roof substrate. Similarly, the paddy
placement arrangement discussed in my '536 patent was likewise
simply placed on a single tile and the tile pulled from the roof.
The test arrangement for the present invention is schematically
illustrated in FIG. 12 and the test arrangement applied to FIG. 3
prior art is schematically illustrated in FIG. 12A. More
particularly, flat concrete tiles with an anchor lug was adhesively
secured to roof substrate 20 as shown. Adhesive deposits for both
systems were kept at the same approximate weight of about 12 to 14
grams. A hole was drilled through the deposits into the top surface
of tile 50 and an anchor pin 100 was attached. A load cell (500
Westweight load cell with a computerized readout) was attached to
anchor pin 100 and the title was pulled from roof substrate 20 with
the maximum force recorded by the load cell. Tests were conducted
at a temperature of about 85.degree. F. with a humidity of 92%
using the same adhesive foam, i.e., assignee's Handi-Stick.RTM.
Roof Tile Adhesive. In all cases, the foam had only cured for 8
hours so the force levels recorded for both adhesive configurations
would be expected to increase had the foam thoroughly cured
although the overall results would not be expected to change.
Results of the tests are tabulated below and show that the bond
strength provided by the U-shaped adhesive of the present invention
is stronger than the bond strength of the prior art system shown in
FIG. 3. When lift tests are conducted with the tiles in their
proper overlying relationship, the full benefit of bight portion 64
can be evaluated and it is expected that the bonding strength of
the present invention for the roof system as a whole will show even
more of an improvement than that shown in the results tabulated
below:
1 U-shaped Prior Art Test Adhesive 1 174 110 2 122 123 3 125 172 4
114 151 5 160 101 6 178 146 Total 873 803 Average 145.5 133.8 Force
(ft-lbs)
[0083] The invention has been described with reference to a
preferred and alternative embodiments. Modifications and
alterations will become apparent to those skilled in the art upon
reading and understanding the Detailed Description of the Invention
set forth above. It is intended to include all such modifications
and alterations insofar as they come within the scope of the
present invention.
* * * * *