U.S. patent application number 12/337961 was filed with the patent office on 2010-06-24 for structural members and structures using them, and methods.
This patent application is currently assigned to HUBER ENGINEERED WOODS LLC. Invention is credited to Joel F. Barker, Mikel Hill, Emily Joyce Ma, Brian M. Peek, Eric Peterson, Joerg Student, Sherry S. Walker.
Application Number | 20100154333 12/337961 |
Document ID | / |
Family ID | 42168207 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100154333 |
Kind Code |
A1 |
Peek; Brian M. ; et
al. |
June 24, 2010 |
Structural Members And Structures Using Them, And Methods
Abstract
Structural members, building structures, and methods for making
them, are provided that are less prone to develop squeaks. The
methods include, in one aspect, placing at least one panel on the
flange surfaces of joists with an activatable adhesive provided
between the panel and the flange surfaces to bond the flange
surfaces to the panels in an effective long lasting manner. In
another aspect, adhesive is introduced into a groove array in a
joist flange surface to attach a panel pre-positioned on the
grooved flange surface. Building frame structures, such as
subflooring assemblies, made by the methods are also provided.
Inventors: |
Peek; Brian M.; (Cornelia,
GA) ; Hill; Mikel; (Flowery Branch, GA) ;
Barker; Joel F.; (Townville, SC) ; Student;
Joerg; (San Francisco, CA) ; Ma; Emily Joyce;
(Atherton, CA) ; Walker; Sherry S.; (Salisbury,
NC) ; Peterson; Eric; (Davidson, NC) |
Correspondence
Address: |
Gardner Groff Greenwald & Villanueva, PC
2018 Powers Ferry Road, Suite 800
Atlanta
GA
30339
US
|
Assignee: |
HUBER ENGINEERED WOODS LLC
Charlotte
NC
|
Family ID: |
42168207 |
Appl. No.: |
12/337961 |
Filed: |
December 18, 2008 |
Current U.S.
Class: |
52/232 ; 52/690;
52/745.19; 52/746.1 |
Current CPC
Class: |
C09J 5/00 20130101; E04B
5/12 20130101; E04C 3/122 20130101; C09J 5/08 20130101; E04B 7/022
20130101 |
Class at
Publication: |
52/232 ;
52/745.19; 52/746.1; 52/690 |
International
Class: |
E04C 2/20 20060101
E04C002/20; E04B 1/00 20060101 E04B001/00; E04C 3/02 20060101
E04C003/02 |
Claims
1. A method of making a building structure, comprising: placing at
least one panel on a flange surface of a plurality of joists
wherein a flange surface of a joist proximate to said panel
comprises an effective amount of an activatable adhesive, and
activating said activatable adhesive thereby bonding the panel and
proximate flange surface.
2. The method of claim 1 further comprising securing said panel to
said joists with fasteners to mechanically secure said panel to
said joists.
3. The method of claim 1, wherein said building structure is
selected from a floor, a wall, a ceiling, or a roof.
4. The method of claim 1, wherein said activating comprises
contacting said adhesive with an activation fluid.
5. The method of claim 1, wherein said activating comprises
spraying an activation solution on said adhesive on said upper
flange surface before said placing of said panel on said upper
flange surface.
6. The method of claim 1, wherein said adhesive comprises a
foamable adhesive.
7. The method of claim 1, wherein said upper flange surface further
comprises a groove array adapted to receive activatable adhesive,
activating fluid, or both.
8. The method of claim 7. wherein said groove array comprises at
least one groove positioning said activatable adhesive on the upper
flanges surfaces of the joist.
9. The method of claim 7, wherein said joist further comprises at
least one joist hole extending from a side opposite the upper
flange surface to said groove array, and said activating of said
adhesive comprises introducing an activator fluid through said
joist hole into said groove array.
10. The method of claim 9, wherein said joist further comprising a
drain hole at a different longitudinal location along the joist
than the joist hole which extends from said groove of said array to
a side opposite the upper flange surface, wherein said activating
of said adhesive comprises said introducing of said activator
solution through said joist hole into said groove array at least
until at least a portion of said activator fluid drains from drain
hole.
11. The method of claim 1, further comprising a carrier film
containing said activitable adhesive.
12. The method of claim 1, wherein said activating comprises
imparting adhesive activation energy to said adhesive sufficient to
induce activation of said adhesive to bond the upper joist surface
and said panel thereto, wherein said activation energy is selected
from sonication energy, radio frequency energy, microwave energy,
heat energy, or pressure energy.
13. A method of making a building structure, comprising placing at
least one panel on a flange surface of at least one joist wherein a
flange surface of said joist proximate to said panel comprises a
groove array adapted to receive flowable adhesive; introducing
flowable adhesive into said groove array in an effective amount for
bonding the panel and flange surface.
14. The method of claim 13, wherein said panel comprises at least
one panel hole extending through said panel, and said adhesive
being injected through said panel hole into said groove array of
said joist.
15. The method of claim 13, wherein said joist further comprises at
least one joist hole extending from a side opposite the upper
flange surface to said groove array, and said adhesive being
injected through said joist hole into said groove array.
16. A structural member comprising an activatable adhesive on a
surface of a joist.
17. The structural member of claim 16, wherein said activatable
adhesive comprises a foamable adhesive, and said joist comprises a
grooved surface adapted for positioning said adhesive before
activation of said adhesive.
18. The structural member of claim 16, further comprising a carrier
film on said joist surface, said carrier film containing said
activatable adhesive.
19. A building structure comprising a plurality of joists having
flange surfaces and at least one panel attached on said flange
surfaces comprising an effective amount of an activated adhesive
attaching said joists to said at least one panel.
20. The building structure of claim 19, wherein said building
structure is selected from a floor, a wall, a ceiling, or a roof.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to structural
members and structures assembled using them, for example, building
structures using joists and panels, such as subflooring, and, to
methods for constructing them.
BACKGROUND OF THE INVENTION
[0002] Flooring systems in typical residential and many commercial
buildings include wood joists and a wooden overlayment, often
referred to as subflooring. In flooring construction, wood joists
typically are set on edge, and a subflooring is secured to the top
edge or flange of the joist with nails, screws or staples.
Subflooring commonly consists of particle board, oriented strand
board (OSB), plywood sheets, or similar materials. Finished
flooring material, such as carpet, tile, linoleum, laminate,
hardwood, or the like, is typically then placed upon the
subflooring, directly or indirectly as placed upon an intermediate
layer arranged on the subflooring.
[0003] In the case of some flooring materials, such as hardwood
stone, tile, granite, and so forth, it can be important that the
floor be stiff and strong to eliminate and prevent problems such as
cracks and crazing. In addition, avoidance of floor squeaks in
flooring materials can be important. Wooden joist-and-subfloor
construction can become prone to squeaks or other undesirable
audible structural noise when walked upon. This squeaking problem
can occur in new and old floors alike. Squeaks can have a number of
causes. Squeaks, for instance, often develop where a gap between
the joist and the subfloor panel permits the panel to flex down and
up as a person walks across the floor. During flexing, the subfloor
can rub against the fastener, such as a decking staple or nail,
causing the squeaking noise. This squeaking noise can arise due to
inadequate fastening of the flooring components during original
assembly, or physical changes that occur in the structural
components in use or over time. For instance, drying or dampness in
the subfloor may cause it to warp or shrink with the result that
the subfloor may pull or bend away from the top of a joist to which
it is fastened.
[0004] It can be very costly or even impractical to repair a floor
squeaking problem. The subflooring often is not easily accessible,
if at all, from beneath the floor in a finished building structure.
Conversely, to obtain access to the problem area of the subflooring
from the top side, it is usually necessary to remove finished
flooring materials, such as wood flooring, floor tiles or
carpeting, that have been fastened over the subflooring, This also
can be problematic or expensive.
[0005] As realized by the present investigators, the floor
squeaking problem ideally needs to be addressed by effective
long-term preventive measures that can be integrated in a practical
and economical manner into the original construction process.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to building structures,
and structural members used in assembling the structures, that are
less prone to making squeaks or other structural noise, and methods
for making them wherein joists are joined with panels with adhesive
in manners to create a more effective and longer-lasting bond
therebetween.
[0007] In one embodiment, a method is provided for making a
building structure that preserves structural members assembled into
the structure in their original installed state, comprising placing
at least one panel on a flange surface(s) of joist(s) with an
activatable adhesive pre-applied between the panel and the flange
surfaces that, after activation, bonds the flange surface(s) to the
panel. Fasteners, such as nails or staples, can also be driven
through the panel and into the joist(s) to mechanically secure the
panel to the joists. In a further embodiment, a plurality of
generally planar panels are adhered and fastened to joists in this
manner with side edges of the panels in approximate abutment with
one another to provide substantially continuous paneling coverage
of the joists. In this manner, a paneled building frame structure
can be assembled that is less prone to develop squeaks or other
audible noise associated with panels An advantage of this
embodiment of the present invention is that an adhesive is applied
in a dormant (un-cured) state until ready to use (activate), and
thus can avoid problems associated with using adhesive in
structural member assembly where the adhesive is dispensed from a
dispenser in an active state of cure.
[0008] In another embodiment, a method is provided for constructing
a subfloor assembly of a building so as to prevent squeaking of the
floor, wherein an activatable adhesive is applied to the upper
flange surfaces of floor joists and at least one floor panel is
mounted on the upper flange surfaces of the joist with the adhesive
pre-applied between the floor panel and the upper flange surfaces
of the joists. The applied adhesive can be activated in place to
more permanently and consistently bond the upper flange surfaces of
the joists to the overlying panel or panels. Fasteners can also be
driven through the floor decking panel and into the joists to
mechanically secure the floor decking panel to the joists. The
adhesive can be activated, for example, via chemical activation or
energy activation, depending on the adhesive formulation.
[0009] In one embodiment, activatable adhesive is pre-applied on
joist flange surfaces in a non-tacky state on the joist flange
surface and then is activated in place with at least one panel
member placed on the adhesive, to adhesively bond the joist and
panel together. In one further embodiment, integral retention
means, such as grooves, can be provided in the surface of the
flange surface for pre-positioning activatable adhesive. In an
alternative embodiment, grooves are provided in the joist flange
surfaces to provide a channel network for flow of activator fluid
to activatable adhesive pre-applied on the joist flange surfaces
(grooved or non-grooved flange surface portions). In one
embodiment, the activatable adhesive is essentially non-tacky at
normal installation conditions. The activatable adhesive can be
activated in place by contacting it with a chemical activator. In
another embodiment, activation of the activatable adhesive on the
joist surfaces can be induced by imparting activating energy to the
adhesive, such as sonic energy, high frequency radiation energy,
heat energy, or pressure (compression) energy, or any combinations
of these.
[0010] In another embodiment, activatable adhesive can be contained
in a non-tacky carrier film placed on the joist flange surfaces
(grooved or non-grooved surface portions), before a panel is place
on the joist. In one embodiment, the carrier film material and
contained activatable adhesive can be essentially non-tacky at
normal installation conditions. The activatable adhesive can be
substantially uniformly dispersed or distributed in, or contained
at discrete areas in/on, a carrier film. In one embodiment, a
carrier film can be placed on the upper flange surface of a joist,
and the adhesive is activated by contacting the film with an
activator fluid, wherein the joist can be bonded to a panel placed
on the opposite side of the carrier film in contact with the
contained adhesive. In an alternative embodiment, the activatable
adhesive in the carrier film can be activated by application of
activating energy.
[0011] In a further embodiment, a method is provided for
constructing a subfloor assembly that comprises providing joists
having upper flange surfaces imparted with a groove array, wherein
an activatable adhesive can be introduced into the grooves before
the panels are mounted on the joists. In one embodiment, the
grooves define an array, such as a pattern, grid, or series of
grooves, for applying and positioning adhesive on the upper flanges
surfaces of the joist. The pre-applied adhesive can be activated in
place in the groove array by spraying it with an activation fluid
before the panel is mounted thereon. In another embodiment, the
groove pattern provided on the joist upper flange surfaces can be
used to provide flow channels through which activator fluid can be
introduced before or after assembly of the joists and at least one
panel, whereby the activator fluid can flow along the length of the
joist surface away from a point of introduction to substantially
contact all the pre-positioned adhesive in the groove pattern. In
one further embodiment, at least one joist hole is provided that
extends from a side opposite the upper flange surfaces to a groove
of the groove pattern, wherein activation of the adhesive comprises
injecting an activator fluid through the joist hole into the
groove, where it can flow throughout the groove pattern and reach
the activatable adhesive pre-positioned on the upper flange
surfaces of the joist. The activator fluid has a characteristic of
allowing or initiating cure in the adhesive. The joists can further
comprise a drain hole at a different longitudinal location along
the joists different than the joist hole, such as at the opposite
longitudinal end of the joist. The drain hole also extends from a
groove of the groove pattern to a side opposite the upper flange
surfaces so that the installer can detect when the amount of
activator fluid injected through the joist hole is sufficient to
reach substantially all the groove pattern when it drains from
drain hole. In another further embodiment, the joists having
grooved upper flange surfaces and at least one panel are united by
activating adhesive positioned therebetween with application of
activating energy relative to the activatable adhesive. In
particular embodiments, activation of the adhesive applied to the
joist surfaces is induced by sonication energy, high frequency
radiation energy, heat energy, or pressure energy applied to the
adhesive sufficient to induce activation of the adhesive. The high
frequency radiation energy can be, for example, radio frequency
energy or microwave energy.
[0012] In one particular embodiment, a method is provided for
constructing a subfloor assembly, which includes the application of
a foamable adhesive to upper flange surfaces of the joists, wherein
the foamable adhesive can be activated to foam in place and wet
both the upper flange surfaces and the panels to provide an
enhanced flange-to-panel bond. The activation of the adhesive in
this embodiment also can be accomplished by using a chemical
activator or energy activator, depending on the selected
formulation of activatable adhesive.
[0013] In another embodiment, a method is provided for constructing
a subfloor assembly with reduced squeaking that comprises providing
at least one joist having an upper flange surface including a
groove array, wherein flowable adhesive is introduced into the
groove array after pre-positioning a panel or panels on the joists.
In one further embodiment, a panel is provided having at least one
panel hole extending through the panel. Adhesive is injected into
the panel hole at the top side of the panel, flows through the
panel through-hole, and discharges from the panel hole at the
bottom side of the panel to be deposited into an underlying groove
of a groove pattern provided in the upper flange surface of the
joists, effective to provide an intermediately-located adhesive
used to bond the joists and panels. In one additional embodiment,
the panel comprises a plurality of panel holes extending through
the panel through which the adhesive can be injected into a groove
of the groove pattern. In an alternate further embodiment, the
joists further comprise at least one joist hole extending from a
side opposite the upper flange surfaces to a groove of the groove
pattern, and the adhesive is injected through the joist hole into a
groove of the groove pattern. The adhesive also can be injected
into the space between the panels and joists. The adhesive can be
introduced, for example, via holes provided through the panels, the
joists, or both. In particular embodiments, the adhesive used in
this embodiment can be self-hardening or activatable, such as where
grooves are used to carry adhesive.
[0014] In another embodiment, a building structure is provided
which can be made with these methods. The building structure can
be, for example, a building frame structure. The building frame
structure can be selected, for example, from a floor, a wall, a
ceiling, or a roof. These types of building frame structures use a
structural element or combination of structural elements to which a
panel is mounted. These structural elements also have a surface
that mates or joins to a portion of the panel material
(subflooring, roof and wall sheathing, drywall, etc.) covering the
structural elements. Buildings incorporating one or more of these
frame structures are also provided. In a particular embodiment, a
joist-supported floor of a building, such as made in accordance
with these methods is provided, as well as a building incorporating
the joist-supported floor structure. In addition, the methods of
the present invention can be applied to assembly of building frames
on-site in building construction or to assembly of prefabricated
building frames fabricated off-site and transported on-site for use
in building construction.
[0015] Other features and advantages of the present invention will
become readily apparent from the following detailed description,
the accompanying drawings, and the appended claims. It is to be
understood that both the foregoing general description and the
following detailed description are exemplary and explanatory only
and are only intended to provide a further explanation of the
present invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a partial schematical view of a subfloor assembly
according to an embodiment of the present invention.
[0017] FIG. 2 is a partial fragmentary view of the subfloor
assembly of FIG. 1 with the panel partially removed to show hidden
structural details.
[0018] FIGS. 3A-3F are illustrations showing steps of a method for
subfloor assembly using joists and a pre-applied adhesive gluing
method according to an embodiment of the present invention.
[0019] FIG. 4 is a top view of a grooved upper flange surface of a
joist including hole through the flange for introducing adhesive
activating fluid therethrough.
[0020] FIG. 5 is a bottom perspective of the upper flange of the
joist of FIG. 4 showing introduction of activating fluid to a joist
hole from the bottom side of the flange.
[0021] FIG. 6 is a top view of a floor joist having a grooved upper
flange surface having an array of dots of activatable adhesive
placed on or over non-grooved portions of the flange surface,
wherein activating solution is introduced into the groove array in
the joist flange surface via a joist hole according to another
embodiment of the invention.
[0022] FIG. 7 is a top view of upper flange surface of a joist
having a groove pattern into which adhesive is introduced via a
hole provided through an overlying panel according to an embodiment
of the invention.
[0023] FIGS. 8, 9, and 10 show examples of adhesive arrays that can
be used in various embodiments according to the invention.
[0024] FIG. 11 is a perspective view of the use of a carrier
film/layer containing activatable adhesive to bond I-joists and
subfloor panels together according to another embodiment of the
present invention.
[0025] FIG. 12 is a perspective view of the use of a visco-elastic
carrier film containing activatable dots of adhesive to bond
I-joists and subfloor panels together according to another
embodiment of the present invention.
DETAILED DESCRIPTION
[0026] The present invention relates to methods of constructing
floors and other building structures with structural members that
are joined at least in part with enhanced adhesive bonding designs
and techniques. These methods and structures can effectively
eliminate squeaks and are economical, convenient to practice, and
can be used in a wide range of construction conditions.
[0027] Referring to the drawings and in particular FIG. 1, in
various exemplary and non-limiting embodiments, a subfloor assembly
101 is constructed, which is made of several structural members
103, 105, 107, and 109 that connect the assembly 101 to a generally
conventional foundation 111 and form the flat surface for
completing the structure. For example, in platform construction the
basic structural components of a floor system can include joists
103, subfloor panels 105, rim board 107, and sill plate 109. These
components are shown in their installed locations in FIG. 1
according to one non-limiting illustration. The longitudinal
direction 102 of the joists 103 is indicated by the arrow in FIG.
1. A panel 105 is installed on top of the joists 103 at upper
flange surfaces 113 thereof using adhesive 117 located
therebetween. Additional details on example adhesive 117 are
provided in the several embodiments illustrated herein. The panel
105 can also be mechanically fastened to the upper flange surfaces
113 of joists 103 with mechanical fasteners 115, such as nails,
screws, or staples, or any combinations thereof. Portions of these
joists and joist components (flanges and web) can be made, for
example, of solid sawn lumber, while others can be formed from
engineered wood products, without limitation. A sill plate 109 is
usually pressure-treated solid sawn lumber, but can be an
engineered wood composite material. The sill plate functions as a
transition from the foundation 111 (typically concrete block or
poured concrete wall) to the rest of the frame structure 101. A
sill plate 109 is usually treated to resist rot and insects, and,
thus, pressure-treated lumber can be a preferred material for this
component. The joists 103 are used to span the distance between two
of the outer foundation walls or from one foundation wall to a
central beam (not shown).
[0028] Referring to FIG. 2, when the joists 103 are installed,
their longitudinal ends 114 typically rest on the sill plate 109.
The sill plate 109 can directly rest on an upper end 112 of the
foundation 111, or, optionally, the sill plate can rest on an
intervening gasket or mortar 116. The joists 103 can be evenly
spaced at specific intervals (usually 12 inches, 16 inches, 19.2
inches or 24 inches on-center) so that subfloor panels 105 can be
set on top of this array of joists 103 to create a flat surface. A
rim board 107 is not necessarily needed or used in all instances.
If rim board 107 is used, it is placed parallel to the sill plate
109 around the outer perimeter of the subfloor system 101 with a
lower edge 118 resting on the sill plate 109. The face 119 of the
rim board 107 is typically perpendicular to the joists 103, such as
in a rectangular shaped room, with the ends 114 of the array of
joists 103 flush against the face 119 of the rim board 107. The rim
board orientation to the joists may not necessarily be
perpendicular for rooms with other shapes, but the concepts of the
present invention, such as illustrated herein, can still be
applied.
[0029] The rim board 107 can be made, for example, from engineered
strand lumber (ESL), oriented strand lumber (OSL), parallel strand
lumber (PSL), laminated veneer lumber (LVL), or solid sawn lumber.
Once the joists are in place, subfloor panels are installed over
the joists to create a uniform, flat surface that will become the
floor of the interior space of the building. Each of these members
can be mechanically fastened to the other. For instance, the sill
plate is usually bolted to the foundation or held down by straps.
The other members of the system can be fastened to their adjoining
members with mechanical fasteners, such as nails, staples, or
screws.
[0030] The subfloor assembly serves many important functions. One
important function of the subfloor assembly is to carry the load of
the walls, roof, interior walls, and any furniture, appliances,
people, etc. into the foundation; in this sense, it serves as a
foundation for the rest of the house or other building structure
(e.g., office building, apartment building, storage building, hotel
building, etc.). For example, FIG. 2 partially shows a wall
structure 121 being formed on the subfloor assembly 101. Therefore,
it should be strong, stiff, and durable and resist the effects of
weather, use and time during years of use. The subfloor is also the
substrate for the finished floor materials, cabinets, HVAC,
plumbing and other subsystems desirable to make a home comfortable
and safe. The subfloor assembly preferably has strong, durable and
has consistent performance. The methods for constructing a subfloor
assembly in accordance with embodiments of the present invention
meet or exceed at least some of these needs and requirements.
[0031] Subfloor panels 105 are typically plywood or OSB. Subfloor
panels can be any practical size, such as with respect to width,
length and thickness. In general, the panels will have planar
dimensions sufficient to span between the flange surfaces of at
least two joists. For example, and not by limitation, some subfloor
panels can be approximately 4 feet by 8 feet and have thicknesses
of approximately 15/32 to 1.25 inch. Panels of other sizes can be
used. Subfloor panels can also include a tongue and groove along
the edges, or other edge features, which allows individual panels
to transfer loads placed on the floor to adjacent panels between
the span of the joists.
[0032] The upper and lower flange dimensions (width, thickness,
etc.) of the joist can vary, and, for example, can be between 1.5
inch.times.1.5 inch up to 3.5 inch.times.2 inch, or other
dimensions, and the flange material can be solid-sawn lumber or
engineered lumber, such as laminated veneer lumber (LVL), parallel
strand lumber (PSL), engineered strand lumber (ESL) or other
similar material. The web material is usually plywood or oriented
strand board (OSB). In addition to I-joists, other joist
configurations also can be used in the practice of the present
invention, such as, for example, open web trusses, solid sawn
lumber configurations, or other joist configurations.
[0033] The use of adhesive can add strength and stiffness to a
floor system and can improve the experience of the occupants of the
building. Some benefits of a stronger and stiffer subfloor assembly
include longer life and durability. Further, the extra stiffness
and strength is desirable if some types of finished floor
materials, such as hardwood, ceramic tile, stone, etc., are
installed over the subfloor. The use of construction adhesive also
improves the environment by reducing squeaks and reducing the
amount of vibration transmitted through the floor. In an unglued or
poorly glued floor, squeaks are noticed in a floor system when an
occupant steps on the floor and the subfloor panels and joists
flex, usually rubbing against a nail. Homeowners or other building
occupants can also notice an unglued or poorly glued floor when
they walk across one part of a room and, for example, hear the
dishes in their china cabinet across the room rattle as they move.
In order to achieve the above benefits, the present investigators
have discovered that it is desirable that the adhesive be applied
uniformly and sufficiently along the joist to more permanently
create a strong bond. Insufficient adhesive along the joist can
create defects that lead to poor performance.
[0034] Gluing problems can be associated with a subfloor
construction that is installed with adhesive applied in a
non-uniform, non-permanent manner to joist flange surfaces, which
problems are avoided by the present invention. Construction
adhesive is known that is supplied in large tubes (generally 23
oz-28 Oz) that can be dispensed from a caulk gun onto joist
surfaces. Construction adhesives have been commercially marketed,
and include, for example, Liquid Nails.RTM. LN 602 or Low VOC
LN-902 (Liquid Nails, Strongsville, Ohio USA), OSI GreenSeries.TM.
Subfloor & Deck High Performance Adhesives, and PL Premium
(Henkel Corporation, Avon, Ohio USA). These adhesives are
commercially available in large tubes that typically need a caulk
gun for application. Problems can occur if these adhesives are
dispensed with caulk guns to bond the top surface of the upper
flange of the joists to the bottom surface of subfloor panels. For
instance, after joists are installed, the framer could load the
caulk gun with a tube of these types of adhesive. If so, the framer
then would cut off a portion of the conical tip on the adhesive
tube to set the size of the adhesive bead. The framer then would
measure several feet (such as four feet to match the typical
subfloor panel's width) from the edge of the floor and reach out
over the open floor and lay down a bead of adhesive on each joist
where the subfloor panel is to be installed. The panel then would
be dropped onto the joists, slid into place, positioned, then
mechanically fastened with nails or screws. The framer then would
move to the next section of subfloor and repeats the process until
the subfloor assembly is completed.
[0035] Still referring to the above comparative construction
scenario in which caulk guns are used by a framer to dispense
construction adhesives on joists, application of the adhesive
across the floor system in that manner is difficult and prone to
application problems that can lead to defects that affect strength,
stiffness, and performance. Gaps are prone to be created at panel
edges where the framer does not go out four feet or when the framer
is in between squeezes on the caulk gun. The size of the bead
extruded depends on where and how the conical tip of the adhesive
is cut and how the installer operates the caulk gun (e.g., how fast
or slow the operator moves the tip, how often the caulk gun is
squeezed, etc.). These difficulties will mean that too much or too
little adhesive is applied to the joist, or that there is a gap in
the glue bead. In addition, because such caulk glues set up within
a limited period of time, construction workers need to place the
panels on the joists almost immediately after the glue has been
dispensed, which interferes with flexibility in managing the
construction tasks of the projects. If a panel is not applied over
the adhesive in a timely fashion, the adhesive dries and must be
removed prior to installing the subfloor panel. Furthermore, in
very hot or cold climates, the caulk glue will set up quickly,
which aggravates this problem. These conditions can be expected to
lead to a floor system that squeaks, is not flat and does not have
the expected stiffness and strength needed to meet the demanding
conditions. Safety is a concern also since the framer will need to
lean out over the open part of the subfloor or walk out onto the
narrow edges of the joists to apply the glue to the joists prior to
laying a subfloor panel in place. The framer applying the adhesive
will also be constantly running out of adhesive and having to
reload the caulk gun because even large 28 oz. tubes of adhesive
will only provide enough adhesive for about two to four panels
depending on the amount applied. This makes gluing the slow or rate
determining step of the assembly process and significantly reduces
the speed and efficiency of the crew laying the floor. Panels may
be laid down without glue or with insufficient glue under the
panel, creating a defect and potential squeak source and lower
assembly performance. In addition, the conical tips of the glue
tubes can be cut off at random places by the person applying the
glue, so the bead sizes can vary with each tube and affect how the
glue is applied. The differences in the amount of glue applied
along the joist create variation in performance across the entire
floor system. The framer applying the adhesive will also tend to
experience hand fatigue since the person will be squeezing the
caulk gun constantly while trying to extrude the thick, high
viscosity adhesive from large 28 oz. tubes using a manual caulk
gun. This situation is aggravated in colder weather conditions
since the adhesive's viscosity increases dramatically with
decreasing temperature, making it even harder to extrude from the
tubes (unless the tubes are warmed until used so that the adhesive
can be squeezed out of the tubes more easily). In addition, when
the panels are slid into place along the tops of the joists the
glue is often scraped off, leaving bare spots where too little no
glue is left to form a bond, making this conventional technique
even less effective. In addition, applying the adhesive with caulk
guns tends to be untidy and messy. Adhesive gets on equipment and
clothes. Adhesives also gets on floors and other surfaces which
need to be cleaned up before other steps in the construction
process can begin. For instance, deposited adhesive that misses the
joists may fall onto a basement floor below that will need to be
scraped off that floor before putting down finish floor materials
thereon.
[0036] The methods of assembly of building frames according to
embodiments of the present invention can be used to address many of
the problems identified above and provide improved adhesive bonding
in building frame assembly during building construction or
preparations therefor. These methods make it easier to apply an
effective amount of adhesive over the bonding surface area
available between the joists and subfloor panels. Facilitating the
application of adhesive over the bonding surface between the joists
and subfloor also improves the floor performance and provide an
improved experience for builders, framers and owners.
[0037] In particular embodiments of the present invention, methods
are provided for assembly of structural sheathing, such as floors,
walls, and roof panels with adhesive bonding of structural elements
and decking or panels with adhesive applied in an amount sufficient
to create a strong, longer-lasting bond between these building
components. With respect to floors, for example, methods are
provided which can reduce or prevent squeaks from developing in the
flooring. In one method according to an embodiment of the present
invention, an activatable adhesive is pre-applied to upper flange
surfaces of flooring joists. The adhesive is activated before or
after floor decking panels are mounted thereon. The pre-applied
adhesive can be activated during assembly by the framing crew such
that a strong, longer-lasting adhesive bond is created between the
joists and adjoining subfloor panels. In one method, the framing
crew activates a specific portion of adhesive on the joist, such as
by spraying an activating solution to the surface of the joist
where pre-applied adhesive is present, prior to installing
individual subfloor panels thereon. In another method, the framing
crew first completes the installation of the whole subfloor,
including mounting or positioning panels on top of the upper flange
surfaces of the joists, and then activates the pre-applied
adhesive. Activation of the adhesive can accomplished, for example,
via a chemical activator or energy activator, depending on the type
of adhesive being used. For example, chemical activatable adhesives
can be activated by pumping an activator fluid into to the
adjoining surface of the joists and subfloor panels sufficient to
contact the activatable adhesive. In an alternative embodiment,
activatable adhesive in the joist and subfloor areas of the
subfloor assembly can be heated directly or indirectly via exposure
to high frequency radiation or vibratory energy, such as radio
frequency, microwave, sonication, etc., or using another suitable
means of activation. For example, the adhesive can be formulated to
be susceptible to dieletric heating via exposure to high frequency
radiation energy such as radio frequency (RF) energy or microwave
energy. The adhesive also can be formulated to be susceptible to
heating via sonication. The induced heating of the adhesive can
render the adhesive flowable/fusible if it is thermoplastic and,
thus, it wets surfaces to be bonded, and/or it can initiate/promote
curing of the adhesive as it wets surfaces to be bonded if it is
thermosettable. The heating can be used to initiate a chemical
reaction, for example, such as in the case of a radical initiator
and acrylic adhesives. In other embodiments, the activatable
adhesive also can be pressure activatable.
[0038] In another method of the present invention, the upper flange
surfaces of the joist component of the subfloor assembly are
provided with grooves formed therein, for example, as an array. The
groove array can be, for example, a grid or crosshatch pattern or a
series of parallel extending grooves, and so forth. The grid
pattern, for example, can include a pattern of intersecting grooves
formed across the surface of the upper flange of the joists, such
as in a diamond pattern. The grid pattern can also incorporate one
or more parallel extending grooves that extend in the longitudinal
direction of the joist. These grooves can be used to position
pre-applied adhesive before joist and panel assembly.
[0039] Adhesive can be pre-applied in a grooved grid pattern
provided in the upper flange surfaces of joists, and the
pre-applied adhesive can be activated during assembly by the
framing crew, by spraying an activating solution to the surface of
the joist where pre-applied adhesive is present, and prior to
installing individual subfloor panels thereon. For example, a
flooring joist can used which has pre-applied adhesive filling a
grooved grid pattern or other array formed in the upper flange
surface of the joist. The adhesive is activated by the spraying of
an activator fluid or solution on the top of the flange, wherein
the activator solution comes into contact with the pre-applied
adhesive. This method also could be implemented by depositing the
adhesive in a grid pattern or as a continuous coat on a non-grooved
smooth upper flange surface of the joists.
[0040] As illustrated, for example, in FIGS. 3A-3F, which is
described in more detail in the examples provided below, in one
embodiment of the present invention, the adhesive is pre-applied in
grooves in the flange surface of the joists. In general, the
framing crew first completes the installation of part of or the
whole subfloor, including mounting or positioning panels on top of
the upper flange surfaces of the joists, and then activates the
pre-applied adhesive by introducing activating solution into the
groove pattern. More particularly, and as shown in FIGS. 3A-3F,
this method performed in a series of six steps or stages 301-306,
and which are performed in that order. In stage 301, glue can be
pre-applied in small grooves onto the I-joist as well as in the
panel tongue and groove. In stage 302, the panel can be dropped in
place on top of the dry joist. In stage 303, positioning is easy
and safe because the work area is dry and not tacky. In stage 304,
the floor can be nailed down. In stage 305, the glue installer
activates the glue with an activating fluid 129, such as solvent.
Predrilled holes in the exposed bottom side of the joist flange
serve as injection points. In stage 306, the solvent travels
through the groove in the flange surface and ultimately emerges at
an opposite end of the joist. As indicated, a drain hole 71 can be
provided on the joist 103 bearing the pre-applied adhesive on its
upper surface. For example, a drain hole can be located near an
opposite longitudinal end of the same joist or elsewhere along the
joist relative to the activator injection hole(s), which will
visually inform the framer that sufficient adhesive activator fluid
has been injected into the groove array when activator fluid 129
drains out of the drain hole 71. In an alternative embodiment, the
activating solution can be introduced into or onto the joists as
the subfloor panels are installed, and the benefits of
pre-application of adhesive can still be realized.
[0041] As shown in further detail in FIGS. 4 and 5, the adhesive
117 is activated by introducing the activating solution into a
central groove 1251 on the top surface of the upper flange from
underneath via a hole 123 drilled completely through the thickness
of the upper flange 127. Access to the central groove 1251 is
gained via a channel intersecting, and thus which can fluidly
communicate with, hole 123 on the bottom side 128 of the upper
flange 127 of joist 103 (shown in FIG. 5). An activating solution
injector device 130 can be used to pump an activator solution
through hole 123 into the central groove 1251 and, from there, the
activator can flow onto the pre-applied adhesive 117 positioned in
a groove pattern 1252, a diamond grid here, that interconnects with
the central groove 1251. The injector device can be a pipette or
other fluid storing, pumping, and dispensing means. FIG. 4 also
shows the widthwise direction 108 of the joist surface, which is
referenced herein, and is oriented orthogonally to the longitudinal
direction 102 of the joist 103. As also shown, joist 103 has
opposite lateral edges 1031 and 1032.
[0042] Referring to FIG. 6, in another embodiment of the present
invention, activatable adhesive 1170 is arranged as discrete dots
on non-grooved portions (flats) of the joist flange surface 113 of
the joist 103 adjacent grooves 1254 of the groove pattern or array
1255. In this illustration, a groove pattern 1255 is repeated along
the length of the upper flange 113. Activator solution is pumped
into the pattern 1255 via access hole 123 (such as discussed with
respect to FIGS. 4-5) to activate the adhesive dots 1170 and bond a
subfloor panel (not shown) and the joist together. In another
embodiment, fluid adhesive is pumped into the groove pattern 1255
via access hole 123 of the joist 103 to bond the subfloor panel and
adhesive together. The activatable adhesive 1170 can be arranged as
separate discrete dots that are deposited directly on the flange
surface. Alternatively, the discrete areas of activatable adhesive
1170 can be contained in a carrier film (such as described in
greater detail with respect to FIGS. 11-12 infra), which is placed
on the flange surface.
[0043] Examples of adhesives that can be used in various
embodiments of this invention include, for example, epoxies,
acrylics, cyanoacrylates, hot melts (ethylene vinyl acetate, LD
polyethylene, alkenyl succinic anhydride, etc.), asphaltic,
oleoresinous, butyl, butyl rubber, polyurethane, neoprene, nitrile
rubber, silicones (with and without silanes or other coupling
agents including organofunctional silanes, Permapol.RTM. family,
Hypalon.RTM., Caesin and other protein adhesive, starch-based,
natural rubber and polyisobytylene, amino resin, phenolic resin
polyvinyl acetate emulsions, polyvinyl alcohol emulsions, polyvinyl
acetal, polyester and polyamide hot melts. These adhesives can also
be blended or combined to produce useful combinations. Categories
of use of these and other types of adhesives for embodiments of the
present invention are illustrated below. These various types of
adhesives can be used singly or in combinations within the same
type or of different types thereof.
[0044] Pre-Applied Activatable Adhesives and Corresponding
Activator Fluids
[0045] This type of adhesive and activator combination can include,
for example, the following: [0046] 1. Hot melts (ethylene vinyl
acetate, LD polyethylene, alkenyl succinic anhydride, etc.),
activated with organic solvents such as acetone, ethanol, methanol,
ethyl acetate, methylene chloride, etc. [0047] 2. MDI/polyurethane,
activated with water (can have catalytic amounts of amines) or
organic solvents listed above. [0048] 3. Polyvinyl acetate
emulsions, polyvinyl alcohol emulsions activated with water and
some milder organic solvents, like methanol, ethanol, etc. [0049]
4. Epoxies where the epoxide component of the adhesive is
preapplied and the hardener component is applied to the adhesive in
a solvent such as ethyl acetate, or alternatively hardener
component can by preapplied and the epoxide component can be
applied in the solvent. [0050] 5. Phenolic novolac resin with an
activator solution of formaldehyde in a solvent. [0051] 6. Acrylics
activatable with a chemical radical initiator.
[0052] Energy Activated Adhesives
[0053] This adhesive type essentially can be any adhesive that can
be formulated to cure in response to heat conditions. Example
include, for example, epoxies, acrylics, anaerobics,
cyanoacrylates, hot melts (e.g., ethylene vinyl acetate, LD
polyethylene, alkenyl succinic anhydride, etc.), asphaltic,
oleoresinous, butyl, butyl rubber, polyurethane, neoprene, nitrile
rubber, silicones (with and without silanes or other coupling
agents including organofunctional silanes, Permapol.RTM. family,
Hypalon.RTM., Caesin and other protein adhesive, starch-based,
natural rubber and polyisobytylene, amino resin, phenolic resin
polyvinyl acetate emulsions, polyvinyl alcohol emulsions,polyvinyl
acetal, polyester and polyamide hot melts.
[0054] Self-Hardening Adhesives (Activation Not Required)
[0055] Examples of this type of adhesive, include, for example,
polyvinyl acetate emulsions, polyvinyl alcohol emulsions,
polyvinyl, polyurethanes, acrylics, anaerobics, cyanoacrylates, hot
melts (ethylene vinyl acetate, LD polyethylene, alkenyl succinic
anhydride, etc. (these can be pumped hot into the space between
joist and panel and allowed to cool), asphaltic, oleoresinous,
butyl, butyl rubber, polyurethane, neoprene, nitrile rubber,
silicones (with and without silanes or other coupling agents
including organofunctional silanes, Permapol.RTM. family,
Hypalon.RTM., Caesin and other protein adhesive, starch-based,
natural rubber and polyisobytylene, acetal, polyester and polyamide
hot melts.
[0056] In other embodiments of the present invention, adhesive is
introduced into a groove array provided in the joist flange surface
after pre-positioning a panel or panels on a joist or joists, and
the joist(s) and panel(s) are bonded together using the introduced
adhesive Grooves provided in the upper flange surface of the joist
can be used to directly distribute introduced adhesive along and
across the joist flange surface between the upper flange surface of
a joist and the bottom surface of an overlying panel that is
already placed thereon. For example, after a framing crew completes
the installation of the joists and subfloor panels, they can inject
construction adhesive into the area between the joists and panels
using the groove pattern to facilitate flow of adhesive along the
length of the joist. Several methods can be used to add or
introduce adhesive to the area between the joist and subfloor
panel.
[0057] In one method applicable to a grooved flange surface, the
framing crew fills the grooves between the joists and subfloor
panels with adhesive introduced from underneath the subfloor
assembly using one hole or a set of spaced holes that extend from
the bottom of the top flange to a central grove machined or
otherwise formed into the top surface of the upper flange. Adhesive
can be injected into the port or hole, which can be similar to that
shown as hole 123 in FIGS. 4 and 5 used for introduction of
activator solution in that above-discussed embodiment. The adhesive
can be pumped into the hole, such as via a pressurized container
(not shown), and into the central groove 1251 on the top surface
113 of the joist 103. The adhesive fills the grooves on the top of
the joist and creates a bond to an adjoining subfloor panel.
[0058] Referring to FIG. 7, in an alternate method, the adhesive
117 is applied from above through a hole or holes provided in a
panel or panels overlying the grooves in the upper flange surface
of a joist. In this embodiment, a panel (not shown) is positioned
over the joist and adhesive is introduced via at least one
through-hole provided through the overlying panel such adhesive can
flow into and fill the series of parallel longitudinally-extending
grooves 1253 provided in the underlying upper flange surface 113 of
the joist 103 in an amount effective to bond the joist and panel
together (not shown). These holes are located over the joists and
spaced so that when adhesive is pumped into the panel holes, the
adhesive fills and follows the series of grooves provided in the
top surface of the joist to completely wet and bond the whole area
between the joist and subfloor panel. In an alternative case of the
pre-applied adhesive being provided on the upper flange surface of
the joist, the right amount of adhesive is already on the joists,
the glue bond is continuous and there are no gaps in the adhesive
bead.
[0059] In this embodiment, the addition of adhesive after assembly
of the subfloor panels means that gaps between the joists and
subfloor panels are filled. In the above methods using either
pre-applied adhesive or adhesive injected between the joist surface
and pre-mounted panel, the mating surfaces available between the
joists and subfloors panels can be effectively used for bonding the
subfloor assembly together creating a stronger, stiffer subfloor
assembly with uniform, consistent performance. The stronger, more
consistent bond means the subfloor will be more durable and perform
better. In addition, framers avoid the tedious steps related to
applying construction adhesive with caulk guns, such as running
out, cleaning messy adhesives, avoiding loss of time, and cleaning
clothes and equipment. Builders will benefit from fewer
"call-backs" because of the improved reliability of installation
resulting in fewer installation mistakes that need to be corrected
after the owner occupies the structure. The present invention can
be a more cost effective means of applying glue in assembly of
building frame structures and can facilitate greater use by
builders of adhesive in assembly and installation of building beam
structures.
[0060] The grooves in the joist flange surface, which carry the
activator fluid or adhesive, depending on the embodiment, to bond
the joist and subfloor panels together, can, for example, be
machined, cut, milled, molded, or otherwise formed into the top
surface of the upper flange. The grooves can be arranged so that
they extend substantially over the flange surface. The groove size
and shape is determined by the means used to join the joist and
subfloor panel. The size and number of grooves will depend on the
intended function. For example, if the grooves are to hold adhesive
to be filled later, such as after panel placement on the joists, a
central groove may be larger with smaller grooves extending outward
to the edges of the upper flange of the joist. If the grooves are
to hold activatable glue, in one embodiment some of the grooves can
be filled with activatable adhesive and the other grooves are left
unfilled with adhesive to route activator fluid introduced to the
grooves partly filled with activatable adhesive. Grooves that are
formed or machined into the top surface of the upper flange of a
flooring joist such that they run parallel to the major axis
(length), can be cut, for example, .about. 1/16 inch to 1/2 inch
deep and spaced, for example, .about. 1/16 inch to 1.5 inch apart.
The spacing of grooves can depend on the adhesive and how easily
the adhesive flows and wets the adjoining surfaces between the
joist and panel. The grooves can be spaced along an axis
perpendicular to the length of the flange. The grooves can be
straight, at a desired angle to the major axis of the joist, or be
curved or wavy. There may also be a second set of grooves that run
across the first set of grooves to interconnect all the grooves and
allow the adhesive to flow over the entire surface of the joist.
Their shape, number and dimensions are selected to provide enough
volume to hold the adhesive while keeping enough surface on the
upper flange so that there is sufficient surface area to bond the
panel to the joist without compromising floor system performance
(while allowing the adhesive to flow without too much back
pressure).
[0061] As described above, the grooves can be machined or otherwise
formed into the top surface of the flange of the joist. Machining
can be accomplished, for example, with a CNC machine programmed
with the appropriate pattern to rout the grooves using a cutter
head of desired shape and size or in a more labor-intensive manner
by using a hand-held router and template attached to the flange to
be machined. Forming the grooves into the upper flange can be
achieved by changing the manufacturing process such that the
grooves are pressed into the surface of the flange material. For
example, a press used to manufacture OSB can be modified with caul
plates which have the negative image of the desired grooves formed
thereon. Therefore, when the OSB mat is pressed and consolidated
into a final product, the grooves are present. It is also possible
that the grooves could be pressed into the surface using a pressure
roller or platen that has the negative image of the desired
grooves. The grooved upper flange can be used to manufacture
engineered I-joists or open-web trusses using the grooved flange
material. The adhesive can be applied before or after manufacturing
the joists, whichever is most convenient.
[0062] Referring to FIGS. 8, 9 and 10, alternative glue line arrays
1171, 1172, and 1173 are illustrated that can be used in
embodiments of the present invention. The glue line does not need
to be a continuous film or bead. The pre-applied adhesive
preferably is arranged in an array. The adhesive array can take
advantage of the total surface area between the upper flange
surface 113 of the joist 103 on the subfloor panel (not shown) and
generates a strong bond between the two adjoining surfaces. The
adhesive array also can correspond to a groove array formed in the
joist flange surface. The adhesive can fill part or all of the
grooves of such a groove array, depending on the embodiment. As
indicated above, for activatable adhesives, one embodiment has
grooves of a groove array only partly filled with pre-applied
adhesive so that the unfilled grooves remain to support flow and
distribution of activator fluid introduced into the groove array.
On the other hand, where flowable adhesive is introduced into the
groove array, it can be introduced in an amount filling part or the
entire grooved array in the flange surface.
[0063] In various embodiments, it is desirable that the adhesive is
not tacky until it is activated. The construction site can be very
dirty and dusty. A tacky or sticky adhesive film would collect dirt
and sawdust that would then lead to lower bond performance or
unbonded areas in the subfloor assembly. In some embodiments of the
present invention, an activatable adhesive system can desirably
remain inert (dormant) and not collect debris until activated.
Activation can be performed before placing panels or after placing
panels on the joists. In some embodiments, an activatable adhesive
system is used that provides sufficient "open-time" (i.e., working
time, assembly time) after being activated to allow framers to
perform assembly activities after activation, such as placement of
the panels on the joists, allowing the panel to be shifted on top
of the joists (e.g., to fit the tongue and groove ("T&G")), and
allowing movement of the panel into final position before,
optionally, fastening into place with nails or screws. A release
liner could be optionally added to the adhesive film on top of the
joist. The release liner has the advantage that it keeps the
adhesive film clean and the removal of the liner could be used as a
means of activating the adhesive film.
[0064] In another embodiment of the present invention, a process is
provided for applying a film of activatable adhesive or a carrier
holding activatable adhesive to a joist, such as an I-joist, for
example, which can include having the joist run under a dispenser
that applies the right amount of adhesive to the top flange of the
joist followed by a drying step. A drying process allows the film
to become non-tacky for transportation and handling. The use of a
carrier holding activatable adhesive in this manner can be used
with appropriate modifications made to an existing process for
I-joist or open web truss manufacture, or other joist
manufacture.
[0065] Referring to FIG. 11, for example, if it is desirable to use
an engineered I-joist with the adhesive film on a carrier, the
application of an activatable adhesive-carrier 140 could be
integrated into a continuous manufacturing process for I-joists,
such as I-joists comprising an upper flange 133 and I-joist web
135. The carrier film can comprise, for example, a polyvinyl
acetate film (PVAc film), a synthetic
elastomer/thermoplastic/thermosetting blend film, or other adhesive
film materials. An example of an activatable bonding film that can
be used as the carrier film, is Scotch-Weld.TM. 583 activatable
bonding film (3M, Saint Paul, Minn. USA), which is heat and/or
solvent (e.g., ethyl acetate) activatable. After the I-joists are
assembled, the continuous joist has the carrier adhesive applied to
the upper flange before going into a drying room. To apply the
adhesive-carrier to the upper flange, the carrier could be unwound
from large rolls and run through a dip tank and squeeze rolls to
work the adhesive into and throughout the thickness of the carrier.
Then, the adhesive-carrier could be applied to the surface of the
joist in a continuous manner that is not disruptive to the current
process. After the adhesive-carrier is applied to the top surface,
the joists can be cut into lengths then go into the drying room,
per the normal process. It is also possible that the
adhesive-carrier can be supplied as a separate item that is applied
at the construction site. The strips of carrier could be tacked or
otherwise physically attached to the top flange of the joists prior
to joist installation and then activated as needed to adhesively
bond the joist and panel and complete the subfloor assembly.
[0066] Referring to FIG. 12, in this embodiment a visco-elastic
carrier 1400 with discrete areas of adhesive 1170 is placed on the
joist surface. In this example, the carrier 1400 has discrete areas
of activatable adhesive 1170 that can be activated by spraying the
activator solution over the top of the joist just prior to setting
the panel (not shown). In an alternative, the adhesive dots 1170
can be activated by activator solution introduced from underneath
the joist by pumping an activator solution via an access hole (such
as described with respect to FIG. 6) into a series of grooves or
channels 1256 formed in the flange surface 113 underneath the
carrier layer 1400. Grooves can be used under any carrier or
film.
[0067] Other enhancements or embodiments also can be optionally
applied. The activating solution used with an activatable adhesive
in embodiments of the present invention can, for example, have a
catalyst, co-reactant, or other ingredients that improve bonding
performance and weather resistance. For instance, a cross-linking
agent can be added to the aqueous solution used to activate
polyvinyl acetate (PVAc) adhesives making the bond more resistant
to water and rewetting/debonding. One example of a cross-linking
agent is formaldehyde or other aldehydic agent.
[0068] Another enhancement is to add materials that make the
adhesive film more sensitive to activation methods. For example,
such adhesives may include use of metallic particles to aid in
heating the adhesive film with microwaves, for example, so that it
will flow and bond. Another means of providing a cross-linking
agent or sensitizing agent is to incorporate filled microcapsules
or microballoons into the adhesive film. The microcapsules can
contain the above-mentioned metallic particles to increase heating.
The microcapsules can also contain a solvent or activating
ingredient that is released once the film is dosed with microwaves,
radio frequency energy, or sonication. The microcapsules burst
releasing their contents and activating the adhesive film on the
joist, thereby creating a durable bond. The microcapsules can also
be sensitive to an ingredient in the activating solution so that
they dissolve and release their contents into the adhesive film to
increase activation and improve bonding performance. One benefit of
using remote vibration or radiation such as sonication or
microwaves, etc. is that repairing squeaks in floors may be more
easily accomplished and with less mess. For example, if an adhesive
film is used that is activated by sonication, the loose area or
unbonded area of a subfloor panel can be set in place by placing a
weight over the spot with the squeak and using a hand-held
sonicator to heat up the adhesive in that spot reactivating the
adhesive and rebonding the panel. To accomplish the same repair
conventionally requires the use of screws that go through existing
finished floor materials. Another previous used method to repair
floor squeaks is to force more subfloor adhesive into the gap
between the joist and subfloor panel which requires access to the
squeaky spot in the floor from underneath the subfloor assembly. In
contrast, sonication could be accomplished from either underneath
or through the finished floor without disturbing the existing
finished materials. A device that can be used or adapted to apply
sonic energy to the activatable adhesives responsive to sonic
energy in the desired manner can be, for example, an Ultrasonic
Hand Welder, manufactured by Abbeon. A device that can be used or
adapted to apply microwave frequency energy to the activatable
adhesives that are responsive to microwave frequency energy in the
desired manner can be, for example, MPG-4 or MPG-4M, manufactured
by Opthos Instruments, Inc. In addition, RF instruments are
available, such as from Megadyne, which could be modified or
adapted based on the current teachings for use in methods of the
present invention. It is also possible to make the adhesive films
heat up when activated to improve bonding performance. For
instance, adding calcium oxide to the adhesive film and then
wetting it with water will produce an exothermic reaction. The
excess heat from the reaction will heat the adhesive aiding flow
and improving bond performance. Other example materials that may be
useful in such self-heating adhesive formulations could be
magnesium-iron oxide or cobalt ferrite nanoparticles. Each of the
materials will react with water or other activator, and produce
excess heat that could be useful to activate adhesives. These
methods may be especially useful if hot melt adhesives are used on
the joist. Typical hot melt adhesives are blends of a polymer,
e.g., polyethylene--polyacetate, a tackifying resin, and a
petroleum wax. The formulation and the components of hot melt
adhesives can be modified to yield the optimal performance, such as
desired melting range and final bond strength.
[0069] The adhesive also can be formulated to provide a
compressible material which can also compensate for or "smooth out"
irregularities and discontinuities between the flange surfaces of
the joists and the bottom surface of the panels so as to eliminate
any gaps which would permit the subfloor panel to work up and down
and cause squeaks. Secondly, the adhesive serves a shock-absorbing
function which helps prevent the transmission of sound vertically
through the floor. For example, foamable adhesives can be used
which provide these benefits.
[0070] As can be appreciated from the foregoing teachings, there
are a number of benefits and advantages that can be derived from
the present invention, which include, for example, the following:
[0071] 1. The application of adhesive is simplified and can be
completed at a convenient time after installation of the subfloor
panels; [0072] 2. The bond between the subfloor panel and upper
flange of the joist utilizes the full surface creating a stronger,
higher performing floor system; [0073] 3. Subfloor assembly is more
efficient since the crew only needs to activate the adhesive or
that step is conducted at a later time; [0074] 4. Safety is
increased since the framer applying glue does not have to lean out
over the open part of the subfloor to apply glue to joists prior to
subfloor panel installation; [0075] 5. Framers do not experience
hand fatigue or need to take measures to warm-up tubes of
construction adhesive in order to apply it easily; [0076] 6. More
effective glue usage, minimizing waste, and reduction of glue
costs.
[0077] Although this invention is described and illustrated herein
in more detail with respect to a subfloor assembly, it will be
understood that the invention has wider application and can also be
applied to other building structures, such as walls, ceilings, and
roofs.
[0078] The present invention will be further clarified by the
following examples, which are intended to be exemplary of the
present invention. Unless indicated otherwise, all amounts,
percentages, ratios and the like used herein are by weight.
EXAMPLES
Example 1
[0079] Pre-filled grooves: In this example, a series of grooves
were machined into the upper flange of an I-joist at an angle of
32.47.degree. to the left and right of the centerline of the top
flange of the joist. The grooves were 1/8 inch wide and 1/8 inch
deep, and spaced nominally 1 inch apart as measured between the
centers of adjoining grooves. These grooves were filled with 1.4
grams per linear foot of Gorilla Glue.RTM. (The Gorilla Glue
Company, Cincinnati, Ohio USA) adhesive. The adhesive was allowed
to sit for at least 2 hours. Then, the adhesive was activated by
spraying water over the surface of the upper flange so that the
water spread across the surface of the flange. A subfloor panel
(type: AdvanTech.RTM. (Huber Engineered Woods LLC (Commerce, Ga.
USA), dimensions: (6 inch.times.8 inch) was placed over the joist,
and the joists and panels were mechanically fastened using clamps.
The adhesive was allowed to cure at room temperature and pressure,
and a bond between the subfloor panel and joist was formed. In this
example, the water allowed the PVA to flow and bond the two
surfaces together.
[0080] In a modification to the above procedure, a hole (diameter:
1/4 inch) was drilled at an angle of approximately 45 degrees
relative to the longitudinal axis of the joist and then 45 degrees
relative to the vertical axis of the joist, from the underside of
the upper flange such that it opened into one of the grooves milled
into the upper flange's top surface. A subfloor panel (type:
AdvanTech.RTM., dimensions: 4 feet.times.4 feet) was place on top
and mechanically fastened to the joist using nails. Then, solvent
(type: water activator was injected in an amount of .about.250 mL.
into the hole described above such that it flowed into the central
groove of the joist and filled the other grooves. When the adhesive
dried, a bond was created between the joist and subfloor panels.
These examples are generally shown in FIGS. 4 and 5.
Example 2
[0081] Adhesive applied through subfloor panel: In this example,
the adhesive was applied after the subfloor panels were placed over
the joists (type: flanges were fabricated from two layers of
commercially available OSB, the web was also constructed of
commercially available OSB, both had a nominal thickness of
.about.3/4 inch). A series of grooves was machined into the upper
flange of a joist (type: fabricated joist described above) before
floor assembly. The grooves were 1/4 inch wide, 3/16 inch deep, and
1/4 inch apart; this series of grooves was centered in the 3.5 inch
wide flange. A subfloor panel (in this instance, a sheet of
Plexiglas was used to observe adhesive flow) with a set of
pre-drilled holes arranged in a line perpendicular to the
longitudinal axis of the joist was placed over the joist such that
the holes aligned with the grooves in the joist, and the panel was
attached to the joist using screws. The set of holes were
approximately 1/4 inch in diameter and each set was formed at about
6-12 inch intervals along the centerline of the panel. Enough
adhesive was added through a hole drilled into the surface of the
subfloor panel to fill the grooves, which was determined by
estimating the volume of adhesive needed to fill the volume of the
grooves and previous experiments using Plexiglas as a substitute
subfloor material to view flow. The adhesive flowed through the
grooves and cured to form a bond between the joist and subfloor
panel. These holes were spaced so that adhesive would flow between
the panels and joists and create a uniform bond. The joists may or
my not have grooves cut into the surface of the upper flange to aid
flow of the adhesive along the length and across the width of the
upper flange of the joists. Gorilla Glue.RTM. adhesive was added by
filling the grooves with a bead of glue through each set of these
holes, and then allowed to stand at room temperature and pressure
for a time period sufficient to form a bond between the subfloor
and joist. It was found that it was desirable to make sure the glue
flowed through all or substantially all the grooves of the groove
array. Therefore, adding a solvent, such as acetone at a ratio of
1:8-1:1 (acetone to adhesive), improved flow and reduced the number
of holes required in the subfloor panel. For example, adding a
solvent (such as acetone) to Gorilla Glue.RTM. adhesive allowed the
adhesive to flow a longer distance along the grooves; the exact
ratio of solvent to adhesive would desirably be optimized. In an
alternative, the top surface of the upper flange can have two sets
of grooves; the first set running parallel to the long axis of the
joist with a second set of grooves cut generally perpendicular or
at an angle to the first set of grooves so that the grooves
interconnect.
Example 3
[0082] Activatable Adhesive Film: A film of polyvinyl acetate
(PVAc) adhesive (Titebond.RTM. Original Wood Glue, Franklin
International, Columbus Ohio USA) was applied to the top surface of
a joist at a rate of 10 g/liner foot (1 linear foot=an area 1.5
inch wide.times.12 inch long) and allowed to dry overnight. The
film was then activated with water at a rate of 6 g/liner foot (1
linear foot=an area 1.5 inch wide.times.12 inch long). After
standing for 0.5 to 3 minutes, the subfloor panel (type:
AdvanTech.RTM.) was placed over the joist (type: SPF lumber
dimensions: approx 1.5 inch wide, 1.5 inch deep and 8 inch long to
simulate a joist flange) with the activated glue film and
mechanically fastened by clamping into place. After drying
overnight at room temperature and pressure, a bond sufficient to
hold the panel and joist together was formed.
[0083] Further enhancements to the above method can be achieved by
increasing the transfer of the activated adhesive from the joist
surface, where it was pre-applied, to the bottom of the subfloor
panel. This increased transfer of adhesive can be achieved in
several ways, and two were tested. The first approach was the
addition of a blowing agent to the adhesive. The blowing agent acts
to expand the thickness of the adhesive film once the adhesive has
been activated. In the second approach, a carrier was used.
Example 4
[0084] Activatable Adhesive Film with Blowing Agent: Three (3.0) g
sodium bicarbonate (Church & Dwight Co. Inc., Princeton, N.J.
USA) was added to 20 g of PVAc emulsion adhesive (Titebond.RTM.
Original Wood Glue, Franklin International, Columbus Ohio USA) and
thoroughly blended with stirring. This mixture was applied by
spreading the mixture to the top surface of a joist (type: SPF
lumber dimensions: approx 1.5 inch wide, 1.5 inch deep and 8 inch
long to simulate a joist flange) at a rate of 8 g/liner foot (1
linear foot=an area 1.5 inch wide.times.12 inch long) and allowed
to dry overnight at room temperature and pressure. An activator
solution of aqueous acetic acid (5% acidity) was applied to the
film at a rate of 2 g activator solution/gram sodium bicarbonate in
the adhesive film. After the adhesive film was wetted with the
activator solution, the film began foaming, and the subfloor panel
(type: AdvanTech.RTM. dimensions: nominally 3/4 inch thick, 6 inch
wide.times.8 inch long) was placed over the joist with the
activated, foaming glue film and also mechanically fastened into
place. After drying overnight, a bond sufficient to hold the panel
and joist together was formed.
[0085] A joist with pre-applied adhesive can also be manufactured
by applying a carrier containing or filled with an activatable
adhesive to the top surface of the upper flange of a joist. The
carrier material can be compressible material, like foam or thick
cloth. The activatable solution is used to contact the carrier
which preferably wets the carrier, and activates the adhesive. Use
of a carrier also allows for other benefits and features to be
added to the floor system. As two examples, if a thicker
compressible carrier is used, the carrier could fill gaps between
the joist and subfloor panel, thus reducing floor flex and
potential rattles and squeaks when the floor is walked on.
Alternatively, a visco-elastic foam can be used as a carrier that
reduces sound transmission.
Example 5
[0086] Activatable Adhesive on Carrier: Two compressible carrier
materials were tested. The first was cotton batting (Hobbs Heirloom
Natural, obtained from Michaels Stores, Inc.). Sixty-four g of PVAc
emulsion was used to saturate a 1/8 inch thick.times.2 inch
wide.times.4 foot long piece of batting which was then applied to
the test joist flange (type: Trus Joist) and allowed to dry at room
temperature and pressure). To test the bonding performance, the
cotton batting filled with adhesive as described above and was
applied a joist (type: SPF lumber dimensions: approx 1.5 inch wide,
1.5 inch deep and 8 inch long to simulate a joist flange). After
drying, the batting carrier/adhesive combination was bonded to the
top surface of the joist. The batting was wetted with water at a
rate of 5 g/liner foot (1 linear foot=an area 2 inch wide.times.12
inch long) and allowed to stand for 0.5 to 3 minutes. Then, a
subfloor panel (type: AdvanTech.RTM., dimensions: 6 inch.times.8
inch) was placed over the joist with the activated glue film and
mechanically fastened into place. After drying overnight, a bond
sufficient to hold the panel and joist together was formed.
[0087] In another example of using a carrier, a piece of foam
(similar to that used in disposable foam paint brushes), which was
.about.1/4 inch thick.times.1.75 inch wide.times.1 foot long, was
filled with 5 g of PVAc emulsion, applied to the top of the test
joist (type: SPF lumber dimensions: approx 1.5 inch wide, 1.5 inch
deep and 8 inch long to simulate a joist flange)), and allowed to
dry. After drying, the foam carrier/adhesive combination was bonded
to the top surface of the joist. After drying overnight, water was
applied to the foam at a rate of 7 g/liner foot (1 linear foot=an
area 1.75 inch wide.times.12 inch long) to activate the
adhesive-containing foam. After standing for 0.5 to 3 minutes, the
subfloor panel (type: AdvanTech.RTM., dimensions: 6 inch.times.8
inch) was placed over the joist with the activated glue and
mechanically fastened into place. After drying overnight, a bond
sufficient to hold the panel and joist together was formed.
[0088] The features of the above examples can be combined. For
instance, it may be advantageous to create a joist that uses one of
the carriers described above where the adhesive applied to the
carrier also contains a blowing agent. In addition, it may be
desirable to combine the use of formed or machined grooves into the
top surface of the upper flange on a joist with the
adhesive-treated carrier. The grooves or channel could be filled
with activating solution and could help provide better and more
thorough activation after the subfloor panels have been installed
over the joists.
[0089] Installation of a structural assembly using the modified
joist and gluing methods, such as exemplified above, adds strength
and prevents and limits movement (or causes members to move
together). In the case of flooring, it also limits and prevent
squeaks.
[0090] From the foregoing, it will be observed that modifications
and variations can be affected without departing from the true
spirit and scope of the novel concepts of the present invention. It
is to be understood that no specific limitation with respect to the
specific embodiments illustrated herein is intended or should be
inferred. This invention can, however, be embodied in different
forms and should not be construed as limited to the embodiments set
forth herein; rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art.
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