U.S. patent application number 10/935821 was filed with the patent office on 2005-03-17 for self-stiffened welded wire lath assembly.
Invention is credited to Davis, Harold R., Rugina, Narcis, Sacks, Abraham, Sacks, Jeffrey L., Spilchen, William.
Application Number | 20050055953 10/935821 |
Document ID | / |
Family ID | 38320619 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050055953 |
Kind Code |
A1 |
Sacks, Abraham ; et
al. |
March 17, 2005 |
Self-stiffened welded wire lath assembly
Abstract
A self-furring wire lath comprises a mesh of transverse and
longitudinal wires welded at their intersections. Stiffening
trusses are formed by bent sections in the transverse wires and
longitudinal wires attached to the shoulders of the bent sections.
A barrier layer material is retained in the lath between the apex
of the bent sections and the principal plane of the lath mesh. The
barrier layer material has apertures that coincide with the
intersections only at the bent sections to enable mesh size
reduction without compromising the barrier layer but still allow
the fabrication of the lath. The lath provides good embedment in
the stucco, reduces cracking and wastage of stucco while remaining
easy to work with.
Inventors: |
Sacks, Abraham; (Vancouver,
CA) ; Sacks, Jeffrey L.; (Vancouver, CA) ;
Spilchen, William; (White Rock, CA) ; Rugina,
Narcis; (Burnaby, CA) ; Davis, Harold R.;
(Vancouver, CA) |
Correspondence
Address: |
George S. Levy
3980 Del Mar Meadows
San Diego
CA
92130-2258
US
|
Family ID: |
38320619 |
Appl. No.: |
10/935821 |
Filed: |
September 8, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10935821 |
Sep 8, 2004 |
|
|
|
09927544 |
Aug 13, 2001 |
|
|
|
6820387 |
|
|
|
|
Current U.S.
Class: |
52/633 |
Current CPC
Class: |
E04F 13/047 20130101;
E04F 13/045 20130101; E04C 5/04 20130101; E04C 5/0627 20130101;
E04F 13/04 20130101; B21F 27/20 20130101 |
Class at
Publication: |
052/633 |
International
Class: |
E04C 003/02 |
Claims
What is claimed is:
1. A welded wire lath comprising: (a) a plurality of generally
parallel transverse wires lying primarily in a first plane and each
departing from the first plane in a plurality of spaced-apart bent
sections, each bent section defined between first and second
shoulder regions; (b) a plurality of generally parallel first
longitudinal wires lying generally in the first plane and
intersecting with and attached to the transverse wires, the first
longitudinal wires including, for at least one of the plurality of
bent sections, at least one of said longitudinal wires being
attached to the transverse wires in a first one of said shoulder
regions; (c) a plurality of generally parallel second longitudinal
wires lying generally in a second plane parallel to and spaced
apart from the first plane, the second longitudinal wires attached
to the bent sections of the transverse wires; and (d) a barrier
layer material disposed between the first and second planes wherein
the barrier layer material is perforated by apertures which
coincide with some but not all of the intersections of the
transverse and longitudinal wires of the first plane.
2. The wire lath of claim 1 wherein said apertures coincide with
said intersections only at said bent sections and said bent
sections extend through said apertures.
3. The wire lath of claim 2 wherein said apertures are round in
shape.
4. The wire lath of claim 3 wherein said barrier layer material
comprises an absorbent paper.
5. The wire lath of claim 4 wherein the barrier layer material has
additional perforations that are substantially smaller than said
apertures and that do not overlap said intersections.
6. The wire lath of claim 4 or 5 wherein said barrier layer
material has slits that do not overlap said intersections.
7. The wire lath of claim 4 further comprising a backing layer
adhesively affixed to said barrier layer material, and wherein said
second longitudinal wires extend between the backing layer and the
barrier layer.
8. The wire lath of claim 1 wherein said apertures are elongated
and extend in a transverse direction.
9. The wire lath of claim 1 further comprising a longitudinal wire
attached to the transverse wires in the second one of said shoulder
regions.
10. The wire lath of claim 1 wherein at least some of said first
longitudinal wires are non round in cross-section.
11. The wire lath of claim 10 wherein at least some of said first
longitudinal wires are flattened and are oriented to lay generally
in said first plane.
12. The wire lath of claim 9 wherein said bent sections are
generally V-shaped.
13. The wire lath of claim 12 wherein the angle formed between each
leg of the V formed by said bent sections and the normal to said
first plane is 45 degrees or less.
14. The wire lath of claim 12 wherein said longitudinal wire
attached to said first shoulder regions and said longitudinal wire
attached to said second shoulder regions are spaced from one
another a distance equal or greater than the height of said
V-shaped bent sections.
15. The wire lath of claim 12 wherein the second longitudinal wires
are attached approximately near the bottom outside of said bent
sections.
16. The wire lath of claim 1 further comprising a plurality of
spaced apart furring spacers on said transverse wires.
17. A building structure comprising a plurality of generally
parallel transverse framing members and a welded wire lath attached
to said framing members, said wire lath comprising: (a) a plurality
of generally parallel transverse wires lying primarily in a first
plane and each departing from the first plane in a plurality of
spaced-apart bent sections, each bent section defined between first
and second shoulder regions; (b) a plurality of generally parallel
first longitudinal wires lying generally in the first plane and
intersecting with and attached to the transverse wires, the first
longitudinal wires including, for at least one of the plurality of
bent sections, a pair of longitudinal wires, one of the pair of
longitudinal wires attached to each of the transverse wires in a
first one of the shoulder regions corresponding to the bent section
and another one of the pair of longitudinal wires attached to each
of the transverse wires in a second one of the shoulder regions
corresponding to the bent section; (c) a plurality of generally
parallel second longitudinal wires lying generally in a second
plane parallel to and spaced apart from the first plane, said
second longitudinal wires being attached to said bent sections; (d)
a barrier layer material disposed between said first and second
planes, said barrier layer material comprising apertures that
coincide with intersections of said transverse and longitudinal
wires only at said bent sections, and wherein said bent section
extend through said apertures; and, (e) said wire lath being
oriented such that said second longitudinal wires are adjacent to
the framing members, each of said second longitudinal wires
crossing a plurality of said framing members, and said first
longitudinal wires being spaced from said framing members.
18. The building structure of claim 17 wherein said framing members
lie in the horizontal plane.
19. The building structure of claim 17 further comprising a layer
of solidified stucco encasing said first longitudinal wires and at
least substantially filling a space between said barrier layer
material and said first longitudinal wires.
20. The building structure of claim 17 wherein said first
longitudinal wires are flattened and are oriented with a wide
dimension substantially parallel to the horizontal plane.
21. A method of fabricating a welded wire lath having a plurality
of transverse wires that are attached to a plurality of
longitudinal wires at intersections between them, said transverse
wires including bent sections thereof, said wire lath further
including a barrier layer material having apertures coinciding with
said intersections only at said bent section, comprising the steps
of: (a) producing a substantially flat welded wire lath mesh of
intersecting transverse and longitudinal wires; (b) processing said
lath mesh to form spaced bends in said transverse wires, said bends
extending portions of said transverse wires out of, and then back
into, the principal plane of said lath mesh; (c) providing a sheet
of a barrier paper material in which a limited number of apertures
are pre-cut in the paper to correspond only to the location of said
bends; (d) presenting said lath mesh and said barrier paper in
overlapping relationship to a welding machine such that said
pre-cut apertures overlap said bent sections of said transverse
wires; and, (e) welding longitudinal backing wires to said
transverse wires through said apertures to thereby retain said
barrier paper onto said lath mesh.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 09/927544 titled Self-stiffened welded wire
lath assembly by Abe Sacks et al., filed on Aug. 13, 2001.
FIELD OF THE INVENTION
[0002] This invention relates to building technology, and in
particular to wire lath which may be used to reinforce coatings,
such as stucco, applied to soffits and other building surfaces.
BACKGROUND OF THE INVENTION
[0003] Some building construction techniques involve the
application of a coating, such as stucco, to a surface. The coating
may be desired, for example, to improve appearance, enhance fire
resistance or to comply with building or fire codes. In the
following disclosure the term "stucco" is used generally to apply
to cementitious plasters or gypsum plasters, including stuccos as
defined in applicable building codes.
[0004] When applying a coating of stucco (or other similar
material) it is generally desirable to provide a lath on the
surface. The lath provides reinforcing for the stucco and holds the
stucco in place. Difficulties can be encountered in applying stucco
to overhanging surfaces such as soffits (i.e. the area under
building eaves) and the undersides of exposed roof areas, such as
porticos. In such areas gravity tends to cause the stucco to sag
after it has been applied.
[0005] The framing for soffits is typically open where the framing
members typically extend transversely across the soffit opening at
regular spacings (for example, 16 inches or 24 inches
center-to-center). A lath is applied across the opening and
attached to the framing members. Stucco is then applied to the
lath. The lath supports the stucco and, after the stucco dries,
reinforces the stucco. Stucco may be applied in various ways
including by hand trowel, or by spraying onto the lath. In either
case significant pressures can be imposed on the lath.
[0006] The lath must meet several requirements. First, it must be
rigid enough to withstand the stresses of the stucco being applied.
If the lath is deflected significantly during installation, then
stucco in areas adjacent to the deflected area will be disturbed
and will likely fall out. Second, the lath must provide adequate
reinforcement so that the stucco coating on the soffit will be able
to withstand maximum expected wind pressures. The lath should have
features which provide good keying and embedment of the stucco over
the entire area of the lath. Third, the lath should be designed in
such a way as to assist in making the layer of stucco even in
thickness. A stucco layer which is uneven in thickness can be prone
to cracking.
[0007] In many applications it is desirable to have a backing
membrane integrated with the lath. A backing membrane prevents
stucco from blowing through the lath. Such a membrane is especially
desirable in applications where stucco will be pumped or sprayed
onto the lath.
[0008] Various types of lath have been developed for soffit
applications. Specialty expanded metal laths are very widely used.
Such laths have been produced by companies such as Alabama Metal
Industries Corporation of Birmingham, Ala. under the trade-mark
(AMICO.TM). AMICO's expanded metal lath products currently
include:
[0009] 1/8" Rib Lath ("Flat Rib"). This lath has eighteen ribs
approximately 1/8 inch high, spaced {fraction (11/2)} inches on
center to provide rigidity for horizontal applications. The lath
has a large number of openings or "keys" which provide keying for
either troweled or machine-applied stucco.
[0010] 3/8" Rib Lath ("High Rib"). This lath has seven longitudinal
ribs, each 3/8 inch deep and eight small flat ribs to provide
additional rigidity for horizontal applications. A herringbone mesh
is located between the ribs to provide keys for good bonding of the
stucco to the lath. Cal Spray Rib ("1/8 Inch Flat Rib"). This is a
more rigid lath which includes strips of kraft paper attached
between the ribs. The added rigidity makes this product well suited
for horizontal applications, such as soffits. The paper helps
reduce the amount of plaster waste and is not intended to be
moisture resistant. A version of Cal Spray Rib having 3/8 inch high
ribs is also available. Similar products have been available from
California Expanded Metals Company (CEMCO.TM.) and others.
[0011] Expanded metal lath products such as those described above
can provide good rigidity and stiffness for their rated spans. They
also provide good keying and hang on surfaces. However, these
products have some disadvantages. First, at the locations of the
stiffening ribs, the stucco is much thinner than it is at other
locations. Furthermore, the ribs present unbroken surfaces which do
not provide opportunity for embedment and keying of stucco. This
typically results in a series of cracks forming along each of the
ribs.
[0012] Another disadvantage of prior expanded metal lath systems is
that the keys are typically quite small. Correct installation
practice requires the edges of adjacent sheets of lath to be
overlapped. However, with small key openings it is difficult to
force stucco adequately through the lath in the overlapping
portions. This results in a weak zone in which the stucco is likely
to crack at each point where sheets of the lath overlap.
[0013] A third difficulty with expanded metal lath is that it is
difficult to cut, especially if the ribs are high. When cut,
expanded metal lath typically exhibits razor sharp edges. This
makes current expanded metal lath products tedious and even
dangerous to install.
[0014] Another group of stucco laths sometimes used for soffits are
wire fabric laths. Wire fabric laths typically comprise a
rectangular mesh of wires which are welded at their intersections.
Wire fabric laths have been available, for example, from the
Georgetown Wire Company, Inc, of Fontana, Calif. under the
trademark K-LATH.TM. Some examples of such laths include:
[0015] Stucco-Rite.TM. standard. This product is a self-furring
sheet of galvanized welded-wire-fabric lath, 16 gauge by 16 gauge,
with 2 inch by 2 inch openings. A perforated absorbent carrier
kraft paper is incorporated into the mesh, and a Grade D water
proofed breather building paper is laminated to the back side of
the kraft paper. A heavy duty version features an 11 gauge
stiffener wire every 6 inches.
[0016] Standard "Gun Lath". This is a flat sheet welded wire lath,
with 2 inch by 2 inch openings, 16 gauge by 16 gauge with a 13
gauge stiffener wire every 4 inches along length of the sheet. An
absorbent, slot perforated kraft paper sheet is incorporated
between the face and back wires. A heavy duty version features an
11 gauge stiffener wire every 6 inches on center.
[0017] "Soffit Lath". This product is similar to Gun Lath with 16
gauge by 16 gauge wires, but with grid spacing at 1.5 inches by 2
inches. The backing kraft paper has smaller perforated openings
which are to provide a more positive keying for the soffit
stucco.
[0018] Wire fabric laths are more worker friendly than the expanded
metal laths in that they are easy to cut, and do not present as
many sharp edges when cut. They are also easy to overlap without
blinding the openings at the overlap areas. This reduces cracking
at overlaps of sheets. Further, there are no stiffening ribs that
can cause cracking. Therefore, the overall finished stucco is much
better since cracking is minimized.
[0019] However, current paper-backed wire laths have two major
disadvantages. First, the relatively large wire grid spacing
provides little hang on surface area for the wet stucco to hang
onto. The perforated backing kraft papers do prevent blow through,
but do not have sufficient keying or suction capability to hang
onto the wet stucco.
[0020] A second disadvantage of current wire lath products is that
they are not as rigid as is desirable. These laths tend to deflect
as the plasterer applies force. After the force is removed the lath
springs back. As this happens fresh plaster in adjoining areas can
be dislodged and fall out. This exacerbates the stucco fall out
problem. Therefore, plasterers must apply stucco to wire lath very
carefully. This is a major disadvantage since it slows down speed
of application. Even so, there is typically a high wastage of
stucco.
[0021] Rigidity can be increased somewhat by using larger diameter
wires. However, increase in wire diameter does very little to
increase stiffness. If wire diameters are increased enough to
provide significant increases in rigidity then the large wires
close to the stucco surface tend to cause the stucco to crack along
the large wires.
[0022] A third disadvantage of some current paper backed wire laths
is that the installed stucco plaster has uneven thickness which may
result in additional cracking of the stucco. This problem of
cracking is exacerbated because the paper, which is tightly
attached to the wire lath itself, prevents the stucco from totally
surrounding the wires of the lath. As a result the attachment of
the stucco to the lath is weaker than would be desired and the
stucco can separate from the lath under certain loading
conditions.
[0023] Jaenson, U.S. Pat. No. 5,540,023 discloses an improved wire
lath in which a layer of backing paper is held in place between two
courses of horizontal wires. The backing paper is not tightly
attached to the lath and allows good keying. However, this wire
lath requires that the welds of the lath be made through perforated
holes in the backing paper. The backing paper must have a hole at
each intersection between two wires. As can be seen in FIG. 1
(prior art), the perforations exist in the backing paper along each
longitudinal wire and have significant size. These holes are a
disadvantage for producing laths with smaller grid spacings, since
the amount of hole area required to accommodate welding becomes
very large, leaving less and less paper area. This is a major
disadvantage for soffit applications since increasing the hole area
results in increased blow-through. Further the kraft paper could
easily tear between holes resulting in even more blow-through.
[0024] Japanese patent application No. 06047691 published on Sep.
9, 1995 (JP 07233611A2) discloses a multi-layer spray wall core
body having a porous sheet between sheets of erected
reinforcements. Japanese patent application No. 09347789 published
on Jul. 6, 1999 (JP11181989A2) discloses another paper-backed wire
lath.
[0025] Despite the wide variety of lathing systems that are
currently available there remains a need for a lath which avoids
the disadvantages discussed above.
SUMMARY OF THE INVENTION
[0026] This invention provides a wire lath that can be made to be
more rigid than current wire lath products, provides good keying,
minimizes blow through, provides good embedment, and overcomes a
number of disadvantages of expanded metal laths.
[0027] Accordingly, in a preferred embodiment of the invention a
welded wire lath comprising a plurality of generally parallel
transverse wires lies substantially in a first plane. The
transverse wires each depart from the first plane in a plurality of
spaced-apart bent sections. Each bent section is defined between
first and second shoulder portions. While the bent sections can
have various shapes, a V-shape is preferred. The bent sections
preferably have a height comparable to the width of the V-shape.
The lath also comprises a plurality of generally parallel first
longitudinal wires. The first longitudinal wires lie substantially
in the first plane. They intersect with and are attached,
preferably by welding, to the transverse wires. The first
longitudinal wires include, for each of the plurality of bent
sections, a longitudinal wire attached to each of the transverse
wires in at least one of the shoulder portions corresponding to the
bent section.
[0028] The lath also comprises a plurality of generally parallel
second longitudinal wires. The second longitudinal wires lie
generally in a second plane parallel to and spaced apart from the
first plane. The second longitudinal wires are attached to the
transverse wires in approximately the middle of the bent sections.
The second longitudinal wires in conjunction with the bent sections
and those first longitudinal wires which are attached at the
shoulders of the bent sections form trusses which provide rigidity
to the wire lath. The trusses may also serve as furring spacers
although separate furring spacers may be provided.
[0029] In preferred embodiments of the invention the first
longitudinal wires include, for each of the plurality of bent
sections, a pair of longitudinal wires. One of the pair of
longitudinal wires is attached to each of the transverse wires in a
first one of the shoulder portions. The other one of the pair of
longitudinal wires is attached to each of the transverse wires in
the second one of the shoulder portions.
[0030] While all longitudinal wires could be attached to all
transverse wires to maximize the strength of the lath, several
variations in the attachment locations are possible. In the first
variation explained above, all longitudinal wires are attached to
the transverse wires at each bent sections: two first longitudinal
wires at the shoulders and one second longitudinal wires at the
middle of the bent section. As a second variation, it is possible
to include in the lath assembly, tertiary longitudinal wires
located in the first plane and attached to the transverse wires at
locations away from the bent sections and between the shoulder
regions of adjacently located bent sections. As a third variation,
it is possible to include some bent sections in the transverse
wires at which, or near which, no longitudinal wires are attached.
Yet another variation uses the bent sections as furring spacers.
Other alternatives are possible that combine these four
variations.
[0031] The wire lath may incorporate a barrier layer disposed
between the first and second planes. In the preferred embodiment
apertures perforate the layer and the bent sections pass through
the apertures. The barrier layer may comprise a suitable building
paper, such as kraft paper, which may be surface treated to improve
the adhesion of stucco. The barrier layer may have additional
perforations, in the form of small apertures or slits, which do not
coincide with intersections of the longitudinal wires and
transverse wires. The additional perforations serve as "keys" for
stucco.
[0032] A backing layer, such as a layer of asphalt-coated paper may
be adhesively affixed to the barrier layer. In this case the second
longitudinal wires may extend between the backing layer and the
barrier layer.
[0033] The wires of a wire lath according to the invention do not
need to be round. In some embodiments at least some of the first
longitudinal wires are non-round in cross section. The non-round
longitudinal wires may advantageously be flattened and oriented to
lie generally in the first plane. This provides increased surface
area for stucco adhesion, and also can facilitate the application
of stucco.
[0034] Further features, aspects and advantages of the present
invention will be more fully understood when considered with
respect to the following detailed description, appended claims, and
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In drawings which illustrate non-limiting embodiments of the
invention:
[0036] FIG. 1 is a schematic perspective view of the Jaenson prior
art wire lath and backing paper showing large perforations
overlaying all intersections of the wire lath.
[0037] FIG. 2 is a perspective view of a welded wire mesh lath in
accordance with the invention;
[0038] FIG. 3 is a cross-sectional view of the welded wire mesh
lath of FIG. 2;
[0039] FIG. 4 is a cross-sectional view of a welded wire mesh
according to an alternative embodiment of the invention;
[0040] FIG. 5 is a perspective view of a welded wire mesh lath
according to the invention which incorporates a barrier layer;
[0041] FIG. 6 is a cross-sectional view of the welded wire mesh
lath and barrier layer taken along line 6-6 of FIG. 5;
[0042] FIG. 7 is a cross-sectional view of a welded wire mesh lath
according to the invention incorporating a barrier layer and a
backing layer adhesively attached thereto;
[0043] FIG. 8 is a cross-sectional view of a welded wire mesh lath
according to the invention incorporating flattened longitudinal
wires, mounted on a horizontal wooden member; and,
[0044] FIG. 9 is a cross-sectional view of stucco being applied to
a welded wire mesh lath comprising concave longitudinal wires.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] Throughout the following description, specific details are
set forth in order to provide a more thorough understanding of the
invention. However, the invention may be practiced without some of
these particulars. In other instances, well known elements have not
been shown or described in detail to avoid unnecessarily obscuring
the invention. Accordingly, the specification and drawings are to
be regarded in an illustrative, rather than a restrictive,
sense.
[0046] Referring to FIG. 2 and FIG. 3, lath 10 according to a
currently preferred embodiment of the invention comprises a
plurality of first generally parallel longitudinal wires 12 which
intersect with a plurality of generally parallel transverse wires
14.
[0047] Wires 12 lie substantially in a first plane PI (best
appreciated by reference to FIG. 3). Similarly, wires 14 lie
substantially in plane PI, save that wires 14 are bent out of plane
P1 at truss locations 15.
[0048] Wires 12 and 14 are welded together at their intersections
11. Wires 12 and 14 preferably extend generally perpendicularly to
one another. The spacing of wires 12 and 14 can be such that square
or rectangular grid openings are created. A set of second
longitudinal wires 13 is also welded to transverse wires 14 as
described below. Wires 12, 13 and 14 may be made of any suitable
materials, such as steel, aluminum, or the like. If made of steel,
the wires are preferably galvanized. Wires 12, 13 and 14 are
preferably of the same or similar diameters. Preferably wires 12,
13 and 14 have cross sectional areas which differ from one another
by 25% or less.
[0049] Longitudinally extending trusses 15 are formed at spaced
locations across lath 10. Transverse wires 14 have bent sections 20
at the location of each truss 15. In each bent section 20 the
transverse wire 14 bends out of plane P1 at a first shoulder 16,
extends outwardly at least to plane P2 and then bends back toward
plane P1 to the point where it rejoins plane PI at a second
shoulder 17. Certain ones of longitudinal wires 12 (indicated by
the reference 12A) are affixed in a shoulder portion at each of
shoulders 16 and 17. Preferably transverse wires 14 bend sharply
away from plane PI at each shoulder 16, 17 with a bend radius of no
more than a few diameters of the transverse wires 14. Preferably
the radii of the bends at shoulders 16 and 17 are less than 5
diameters of transverse wire 14 and most preferably less than 2
diameters of transverse wire 14. In each truss 15, a longitudinal
wire 13 of a plurality of second longitudinal wires is affixed to
transverse wires 14 on bent sections 20. Bent sections 20 are
preferably generally V-shaped, as shown in FIG. 2 and FIG. 3. In
preferred embodiments of the invention each transverse wire 14,
including bent sections 20, lies in a plane which is generally
perpendicular to plane P1.
[0050] Longitudinal wires 12A are preferably attached to each
transverse wire 14 at a point which is as close as practical to a
point at which the transverse wire 14 bends out of plane P1.
Longitudinal wires 12A should be attached to transverse wires 14 at
points which are spaced away from the points at which transverse
wires 14 begin to bend out of plane P1 by no more than about 5-8
times the diameters of transverse wires 14 (and preferably no more
than 1-2 times the diameters of transverse wires 14). The term
"shoulder region" includes those points which are close to
shoulders 16 and 17 (i.e. are spaced away from the points at which
transverse wires 14 leave plane PI by no more than about 8 times
the diameter of transverse wires 14).
[0051] It can be seen that lath 10 includes longitudinal wires in
two groups. A first plurality of generally parallel longitudinal
wires 12 (which includes wires 12A and others of wires 12 which are
not affixed at bent sections 20) lies generally in a first plane P1
(FIG. 3). A second plurality of generally parallel longitudinal
wires 13 are affixed to transverse wires 14 on bent sections 20 and
lie generally in a plane P2 which is spaced apart from plane P1 by
a distance h. Preferably bent sections 20 of transverse wires 14
bend back toward plane P1 at a distance of approximately h from
plane P1 (so that second longitudinal wires 13 are located at the
"peaks" of bent sections 13). However, this is not essential. Bent
sections 20 could extend away from plane P1 to locations past plane
P2 before bending back toward plane P1.
[0052] The depth h of the truss 15 is preferably equal to the
distance w between the two longitudinal wires 12A on either side of
the truss, but may be have a dimension up to twice w in some
applications. For example, if a truss 15 has a depth of 3/8 inches
then the longitudinal wires 12A along its shoulders can be spaced
apart from 3/8 inch to 3/4 inch. In a preferred embodiment of the
invention, the wires 12 in plane P1 are spaced apart by generally
equal distances x (see FIG. 3) whereas wires 13 are spaced apart
from adjacent wires 12A by a smaller distance y. Preferably y is
roughly 1/2 of x. In another embodiment of the invention x and y
are equal. Each truss 15 has at least one longitudinal wire 13
which is displaced out of the plane of the other longitudinal wires
12. Longitudinal wires 12A extend along at least one of the
shoulders of truss 15. Preferably each truss 15 includes a pair of
longitudinal wires 12A, one attached to transverse wires 14 in the
shoulder region on one side of the truss and the other attached to
the transverse wires 14 in the shoulder region on the other side of
the truss.
[0053] It can be seen that trusses 15 enhance the rigidity of lath
10 in the longitudinal direction. Trusses 15 also make lath 10
self-furring. The number and depth of trusses 15 and the thickness
of wires 12, 13 and 14 may be selected to achieve a desired
strength. Preferably:
[0054] The spacing x between longitudinal wires 12 is in the range
of about 1/2 inch to 2 inches;
[0055] The spacing between adjacent transverse wires 14 is in the
range of about 1 inch to 2 inches;
[0056] The spacing between trusses 15 is in the range of about
1-{fraction (12)} inches to 6 inches.
[0057] For soffit lath applications, preferably:
[0058] The spacing x between longitudinal wires 12 is in the range
of about 0.5 to 0.6 inches;
[0059] The spacing between adjacent transverse wires 14 is about
1-1/2 inches; and,
[0060] The spacing between trusses 15 is about 2 inches.
[0061] In an example embodiment, lath 10 has:
[0062] nominal spacing of about 0.6 inch between adjacent
longitudinal wires 12;
[0063] nominal spacing of about 1-1/2 inches between adjacent
transverse wires 14;
[0064] wires 12, 13 and 14 formed from 17 gauge (0.051") diameter
wire;
[0065] trusses 15 having a depth (i.e. the dimension h) of about
3/8 inch; and,
[0066] trusses 15 spaced apart from one another by about 2
inches.
[0067] Lath 10 may be applied over framing members, which are
typically 16 inches or 24 inches on center. Lath 10 can be attached
to the framing members at the bottom of trusses 15. In horizontal
applications, building codes generally require that a lath be
attached every 3 inches. In vertical applications, the codes
generally require attachment to the framing members every 6 inches.
In either case, a 2 inch spacing of the corrugating ribs allows
appropriate attachment points. Lath 10 is preferably applied in an
orientation such that the side of lath 10 bearing second
longitudinal wires 13 faces the framing members, each of the second
longitudinal wires crosses a plurality of the framing members, and
first longitudinal wires 12 are spaced apart from faces of the
framing members by the distance h. The portions of lath 10 between
the framing members can be substantially unsupported.
[0068] A wire lath 10 can be produced in any desired dimensions but
is preferably provided in sheets of widths of sizes that can be
easily handled. For example, the sheets may have a width in the
range of 2 feet to 5 feet. It can be appreciated that sheets of
wire lath 10 can be compactly stacked together with the trusses 15
of one sheet being received within the trusses 15 of the next sheet
of wire lath 10 in the stack.
[0069] A wire lath 10 may be made by making a sheet of welded wire
mesh and then bending transverse wires 14 at predetermined
locations to form bent sections 20 such that trusses 15 are formed.
Where each truss 15 is formed, a longitudinal wire 13 is displaced
out of the plane of the longitudinal wires 12.
[0070] It can be appreciated that the provision of trusses 15 can
make a lath according to this invention significantly more rigid
than prior wire laths. This can be achieved without using
jumbo-sized wires which can tend to cause cracking. Further, since
trusses 15 are open, stucco is continuous at trusses 15. This is a
major advantage over prior ribbed expanded metal laths in which the
ribs cannot be fully embedded in stucco.
[0071] The wire lath of FIG. 2 and FIG. 3 may be varied in various
ways within the scope of the invention. By way of example only,
bent sections 20 may have shapes other than V-shaped. For example,
bent sections 20 may be U-shaped, trapezoidal, square, generally
rectangular, semi-circular, or the like. It is preferable that the
sections 14A of transverse wires 14 which extend between each wire
13 and an adjacent wire 12A extend steeply to plane P1. Preferably
angle .upsilon. is 45 degrees or less. Most preferably angle
.upsilon. is 30 degrees or less. While it is not as structurally
sound, a longitudinal wire 12A could be provided along only one
shoulder of each truss 15 instead of along both shoulders, as
shown.
[0072] More than one longitudinal wire 13 may be provided on each
truss 15. If two closely-spaced longitudinal wires 13 are provided
on each truss 15 then lath 10 may be fastened to a building
structure with fasteners such as nails or screws inserted between
the two longitudinal wires 13.
[0073] In the embodiment of FIG. 3, longitudinal wires 13 are on
the opposite side of transverse wires 14 from the first
longitudinal wires 12. Conversely as shown in FIG. 4, longitudinal
wires 13 could also be located on the same side of transverse wires
14 as first longitudinal wires 12. Similarly, all of longitudinal
wires 12 and 13 could be on the same side of transverse wires 14 as
bent sections 20.
[0074] A wire lath according to the invention can include a barrier
layer 22, such as a layer of kraft paper, disposed between planes
P1 and P2. FIG. 5 and FIG. 6 show a wire lath 10A which includes a
barrier layer 22. Apart from the incorporation of layer 22, lath
10A is the same as lath 10. Layer 22 has apertures 24. Bent
sections 20 pass through apertures 24. Longitudinal wires 13 are on
one side of layer 22 and longitudinal wires 12 are on the other
side of layer 22. Barrier layer 22 may comprise a layer of paper.
The paper is preferably absorbent and may have a surface treatment
such as sanding or microperforation to enhance its adhesion to
stucco.
[0075] It can be seen that layer 22 does not prevent stucco from
fully embedding longitudinal wires 12 or transverse wires 14 due to
the furring provided by the bent sections. The furring creates a
space between plane P1 and plane P2 so that stucco can embed wires
12 by forcing layer 22 against longitudinal wires 13 as the stucco
is applied. It can further be seen that layer 22 requires
relatively few apertures 24. Layer 22 provides protection against
blow-through of stucco. Apertures 24 may be elongated. If so, then
preferably apertures 24 would be oriented to be generally parallel
to transverse wires 14.
[0076] Wire lath 10A may be fabricated by first welding the
plurality of first longitudinal wires 12 to transverse wires 14,
applying layer 22 and subsequently welding longitudinal wires 13 to
bent sections 20 of transverse wires 14. Bent sections 20 may be
formed while applying layer 22 and welding longitudinal wires 13 to
transverse wires 14. Forming bent sections 20 reduces the width of
the sheet of lath 10A. By orienting the apertures 24 parallel to
transverse wires 14, the wires of lath 10A can slide sideways
without crumpling layer 22. The amount of width reduction will be
zero in the center of lath 10A and will increase progressively
towards the two outer edges. This can be accommodated by making
apertures 24 in the form of elongated slots having lengths which
are greater for trusses 15 located toward the outer edges of lath
10A.
[0077] If bent sections 20 could be fully formed before applying
layer 22 then apertures 24 would not need to be elongated and could
be, for example, round. This would serve to limit the overall size
of the apertures and provide greater control over the keying of the
stucco through the apertures. Accordingly, the preferred method of
fabricating the lath according to the invention involves first
producing a welded lath mesh that is substantially flat. The
resulting lath is then processed through a continuous roll forming
machine so as to provide spaced bends in the transverse wires 14
corresponding to shoulder wires 12A. The bends extend portions of
transverse wires 14 out of, and then back into, the principal plane
of the lath P1.
[0078] A sheet of a suitable barrier paper is provided in which a
limited number of apertures are pre-cut in the paper to correspond
only to the bent areas of transverse wires 14. The lath and paper
are then presented in overlapping relationship to a welding machine
such that the pre-cut apertures in the paper overlap the bent
sections of transverse wires 14. Backing wires 13 are then welded
to transverse wires 14 through the apertures to retain the paper
onto the lath.
[0079] It will be appreciated that whereas the first mentioned
approach above requires apertures in the form of slots to avoid
crumpling of the backing paper during the furring process, the
preferred approach avoids the need for elongated apertures. Each
approach however, avoids the need for an aperture at each wire
intersection, such as is found in the prior art paper web welded
lath structure exemplified by Jaenson U.S. Pat. No. 5,540,023. The
preferred approach requires apertures only at the intersections of
the transverse wires 14 and the backing wires 13. A reduction in
the mesh size of the Jaenson lath results in the apertures of each
intersection being closer together and ultimately running into each
other. This reduces the effectiveness of the barrier layer in
limiting the amount of stucco flow-through. It also weakens the
barrier layer and makes it more prone to tearing, particularly when
subjected to the pressure of stucco being applied. The preferred
embodiment of the present invention avoids such disadvantage by
providing fewer apertures.
[0080] In addition, the Jaenson design represented an improvement
over the previous prior art in that two out of three longitudinal
wires were fully exposed to the stucco. However, every third
longitudinal strand of Jaenson is on the back side of the backing
paper. According to the present invention, all of the longitudinal
wires 12 are on the outer (stucco) side of the backing layer. This
enhances the ability of the lath to provide to fully embed in the
stucco as compared to Jaenson.
[0081] Layer 22 may optionally include a series of additional
perforations 25. Perforations 25 provide further keying and assist
in holding wet stucco to layer 22. Perforations 25 may be extremely
small, from micrometer to sub-millimeter size, or they could have
larger dimensions up to the mesh grid size. When stucco is being
applied, some of the stucco can force its way through perforations
25. The perforations 25 trap some stucco, which will tend to
mushroom out on the rear side of layer 22 (i.e. the side of layer
22 toward longitudinal wires 13). The blob of stucco on the rear
side of layer 22 locks around the edge of perforation 25 thereby
promoting adhesion of the wet stucco to lath 10A. In one embodiment
of the invention, perforations 25 comprise slits formed by cutting
layer 22 without removing any material. Perforations 25 could be
X-shaped, as shown, H-shaped, semi-circular, or some other shape.
Perforations 25 could also comprise holes of various shapes in
layer 22. For example, the holes could be round, oval, elongated or
other shapes.
[0082] As shown in FIG. 7, a wire lath 10B according to another
embodiment of the invention has a backing layer 30 of building
paper or the like may be applied behind longitudinal wires 13.
Layer 30 may be affixed to layer 22 with a suitable adhesive. Layer
30 may comprise, for example, an asphalt-saturated-type building
paper or one of the various building wraps. Where a backing layer
30 is provided then perforations 25 in layer 22 are not
advantageous. FIG. 8 shows a wire lath 10C according to another
embodiment of the invention. Lath 10C differs from laths 10A and
10B in that longitudinal wires 12 are replaced with shaped wires
12'. Shaped wires 12' have shaped cross sections instead of
circular cross-sections. Wires 12' may be, for example, flattened,
oval, square, half-round, concave or other non-round formed shapes.
Lath 10C has the advantage that the surface areas of wires 12' is
increased. This provides enhanced grip when stucco is applied. A
further advantage of this embodiment is that the process of shaping
longitudinal wires 12' can work-harden wires 12'. This can increase
their strength. Thus, a lath using shaped wires 12' may use smaller
wire sizes to obtain similar strengths. This, in turn, makes such a
lath easier to cut to size, lighter and potentially less costly in
materials. The lath of FIG. 8 is shown attached to a
transversely-extending stud 36 by way of a nail 38 which captures
longitudinal wire 13 against stud 36.
[0083] Another advantages of using flattened shaped wires 12' is
that appropriately shaped wires can help to direct stucco into lath
10C as it is troweled into place. FIG. 9 illustrates an embodiment
of the invention wherein shaped wires 12' are flattened and have
their edges curved slightly downwardly. As stucco 40 is troweled
across lath 10C using trowel 45, in the direction indicated by
arrow 42 shaped wires 12' cut through the flowing stucco and tend
to cause part of the stucco to flow upwardly, as indicated by
arrows 44.
[0084] In the laths described above, trusses 15 play the dual role
of providing rigidity and serving as furring spacers. It would be
possible to add other furring spacers to transverse wires 14 at
locations away from trusses 15. The furring spacers may comprise,
for example, additional bent sections in transverse wires 14. Where
the lath comprises a backing layer 22 the furring spacers pass
through apertures in backing layer 22 in substantially the same
manner that bent sections 22 pass through apertures 24. The
separate furring spacers provide points for attachment of a lath
according to the invention to a building structure and are located
away from trusses 15. The use of separate furring spacers thus
reduces the risk that trusses 15 may be damaged while a lath is
being installed. The furring spacers may be formed, for example, by
creating bent sections in transverse wires 14 such that selected
ones of longitudinal wires 12 is displaced into or behind plane P2.
The lath may then be installed, by attaching the furring spacers to
a stud, for example, by nailing, stapling or screwing.
[0085] This invention also includes a building structure comprised
of parallel transverse framing members to which the lath
constructed as described above, is attached such that the second
longitudinal wires of the lath are crossing, and are adjacent to,
the parallel transverse framing members, and the first longitudinal
wires are spaced apart from the framing members. The framing
members could be spaced apart by more than 12 inches leaving the
wire lath substantially unsupported in its portions between the
framing members. Such building structure could be located on an
underside of a part of a building.
[0086] The building structure could also comprise stucco such that
a layer of solidified stucco encases the first longitudinal wires
and at least substantially filling a space between the barrier
layer and the first longitudinal wires. If perforations are made
through the barrier layer, the stucco would flow through these
perforation when it is still wet and would therefore extend beyond
the barrier layer.
[0087] The first longitudinal wires can be flattened and oriented
with their wide dimension substantially parallel to the framing
members.
[0088] As will be apparent to those skilled in the art in the light
of the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from
the spirit or scope thereof. For example, a lath according to the
invention could include additional longitudinal or transverse
wires. Accordingly, the scope of the invention is to be construed
in accordance with the substance defined by the following
claims.
* * * * *