Note: Descriptions are shown in the official language in which they were submitted.
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ROOFING MATERIAL WITH GRANULAR SURFACE
Field of the Invention
The present invention is in the field of roofing materials. More particularly,
the present
invention is in the field of roofing membrane materials having a granular
surface to provide
traction to roofing installers during construction of the roof.
Background of the Invention
Asphalt based roofing shingles are presently installed on approximately eighty
percent of
the homes in the United States. In areas where snow accumulates, roof shingles
can develop
leaks as a result of ice dams which can form along the eaves of a roof. Ice
dams form as the
result of a differential temperature which occurs between the eaves of the
roof and the interior
sections of the roof. The temperature differential occurs when heat rises into
the attic space.
Under certain temperature conditions, snow collected on the roof surface will
melt along the
upper interior portions of the roof and then freeze when the liquid snow-melt
reaches the cooler
eave section of the roof. As can be seen in FIG. 1, the result is that a pool
1 of liquid water can
form between the roof surface 2 and the ice dam 3. The ice dam 3 prevents the
water from
reaching the gutter 4 and draining away. Ultimately, the liquid water 1 can
leak 5 through the
roof surface 2, causing interior water damage to the structure. Ice dams can
also occur as a result
of frozen slush accumulating in gutters, also causing liquid to collect and
leak through the roof.
In a typical roofing installation using asphalt shingles, an underlayer is
first applied to the
plywood deck of the roof. The underlayer may take the form of an asphalt
saturated paper which
is useful as a waterproofing member. Roofing shingles are applied on top of
the underlayer with
the seams of adjacent rows positioned in an offset relationsliip. In practice,
a starter row or strip
is begun at the roof eaves using self-sealing shingles. The end of the first
shingle in the strip is
trimmed such that, when it is placed on the deck, the cutouts of the first
course of shingles will
not be placed over the starter strip joints. The starter strip and the
shingles are nailed to the
eaves. Successive rows of shingles are then secured to the deck or roof using
nails.
To ensure maximum protection against ice dams, membranes or metal flashing is
installed wherever there is a possibility of icing, such as along the eaves of
the roof. As noted
above, ice dams are formed by the continual tliawing and freezing of melting
snow, or the
backing up of frozen slush in gutters, which force water under the roofing,
thereby causing
damage to a structure's ceilings, walls, and insulation. The ice damming
problem is most acute
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on low-slope roofs; that is, roofs with a slope of two inches (5.08 cm) to
four inches (10.16 cm)
per foot (30.48 cm).
Traditional eaves flashing has either been 50-pound coated felt or two layers
of 15-pound
saturated felt cemented together. The term "pound" is defined as the weight of
the felt required
to cover an area of 108 square feet. Typically, the asphalt used in the fifty-
pound felt is not
modified with rubber, and after aging, will not form a good seal around nails.
Additionally, the
installation of two layers of 15-pound saturated felt consumes undesirable
amounts of time and
also will not seal around nails.
The use of self-adhesive products, such as ice and water protective membranes,
has now
become commonplace. A major problem with these products is that they are
slippery, especially
when wet or covered with frost. Slippery surfaces upon roofs create
significant safety hazards
for roofing installers, especially since such surfaces tend to be at least one
story above ground
level.
Summary of the Invention
The present invention relates to roofing membrane materials having a surface
like
sandpaper to provide traction to workers during construction of the roof. More
particularly, the
present invention relates to a roofing membrane material having a rubberized
asphalt layer
liaving an upper surface and a lower surface, a supporting layer disposed on
the upper surface of
the rubberized asphalt layer, and a traction layer disposed on the supporting
layer.
For preventing multiple layers of the membrane from adhering to one another
during
shipping and storage, a release sheet can be applied to the lower surface of
the rubberized asphalt
layer. As a result of the release sheet, when the membrane is rolled, or when
several layers of the
membrane are stacked together, the release sheet is interposed between the
sticky lower surface
of the rubberized asphalt and the adjacent traction layer. By interposing the
release sheet,
adhesion between subsequent layers of the membrane material is prevented. Of
course, prior to
application to a roof surface, the release sheet is removed, thereby allowing
the sticky underside
of the membrane to adhere to the roof.
One object of the present invention is to provide rubberized asphalt roofing
product
wliich can be applied along the eaves of a roof to serve as a water
infiltration barrier for the first
course of overlying shingles.
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Another object of the present invention is to provide a roofing membrane
having a non-
slip surface for the safety of roof installers.
These, and additional features and advantages of present invention, will
become more
apparent from the following detailed description when taken in conjunction
with the 5
accompanying drawings.
In particular the present invention provides a roofing membrane material which
comprises:
a) a rubberized asphalt layer having an upper and lower surface;
b) a supporting layer disposed upon the upper surface of the rubberized
asphalt layer; and
c) a traction layer disposed upon the supporting layer,
wherein the traction layer comprises a film having embedded grit particles
Brief Description of the Drawings
FIG. 1 is a side elevational view of a portion of a roof showing an ice dam.
FIG. 2 is a sectional view of the roofing membrane of the present invention.
FIG. 3 is a perspective view of the eaves of a roof having the membrane of the
present
invention, and several shingles, applied thereto.
FIG. 4 is a side elevational view of the portion of the roof shown in FIG. 2,
with the
shingles removed for the purpose of clarity.
Detailed Description
The present invention relates to self-adhesive membranes which have been
developed
to eliminate problems associated with ice dams. The inventive membranes have a
top surface
or internai reinforcement which supports a sticky, rubberized asphalt bottom
layer that adheres
directly to the wood deck of a roof. Roof shingles may then be applied
directly over the
membrane. The membrane prevents water entry into the structure by adhering to
the deck and
sealing around the nails which are used to hold the shingles to the roof deck.
To date, two types of self-adhesive membranes have been developed to solve the
ice
dam problem: granular surfaced membranes and polyethylene surfaced membranes.
The
present invention relates to the polyethylene surfaced membranes and sets
forth improvements
thereto.
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25 Typical polyethylene surfaced products are either embossed or coated to
reduce the slip hazard
to the roofing installer. Since the roofer must stand on the membrane during
its application to
the roof deck, surface traction on the membrane is a significant safety issue.
The present
invention increases surface traction on the membrane in a novel way.
Specifically, the
polyethylene is coated with a urethane, and then grit is applied to the
urethane prior to curing to
form a material
30 having a surface similar to sandpaper. Other coatings that adhere to
polyethylene and will
harden but remain flexible, include epoxy, polyester, varnishes, EVA and the
like may also be
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employed to cover the polyethylene and secure the grit. The coating may be UV
or oven curable,
or it may be liot melt.
In its broadest sense, the present invention comprises a roofing membrane
material
having a rubberized asphalt layer, a supporting layer and a traction layer.
FIG. 2 depicts a
roofing membrane material 10 of the present invention. More particularly, as
can be seen in
FIG. 2, the roofing membrane material 10 comprises a multilayered structure
formed of a
rubberized asphalt layer 12, having upper 14 and lower 16 surfaces, a
supporting layer 18
disposed on the upper surface 14 of the asphalt layer 12, and a traction layer
20 disposed on the
surface of the supporting layer 18 which is not in contact with the upper
surface 14 of the asphalt
layer 12. A traction material, such as a grit 22 or mineral particles is
embedded in the surface of
the traction layer 20 to provide a relatively non-slip surface. Optionally, a
release sheet 24, such
as a paper or plastic film having a siliconized surface 26 can be adhered to
the lower surface 16
of the asphalt layer 12. The release sheet 24 is removed prior to use of the
membrane material to
allow the lower surface 16 of the asphalt layer 12 to be adhered to a roof
surface.
The above-described structure addresses many of the needs currently embodied
in the
roofing industry. For example, the rubberized asphalt layer 12 provides a good
seal between the
membrane and the roof surface to prevent moisture from penetrating into the
roof, even if ice
dams are formed on the eaves of the roof. The rubberized asphalt layer 12,
elongates and
recovers around the nails, thereby providing an excellent seal around nails
that pass through the
material to secure shingles to the roof surface. The supporting layer 18
serves to maintain the
structure of the material. Finally, the traction layer 20 serves to provide a
non-slip surface to the
portion of the membrane material 10 that will be stepped on by roof
installers. This non-slip
surface olTers the rooGng installcrs grcatcr traction, and tlius, grcater
safcty, whcn installing the
roof, even in wet or otherwise slippery conditions.
The rubberized asphalt layer 12 generally comprises a material having from
about 0-30%
mineral stabilizer, (i.e., powdered limestone), about 5-15% styrene-butadiene
copolymer or
styrene-butadiene-styrene copolymer, and the balance being flux asphalt having
a Ring and Ball
softening point of between about 80 F and about 150 F, (i.e., between about
26.67 C and about
65.56 C). Additionally, a tackifying oil, such as Hydrolene may be added.
The supporting layer 18 is preferably a polyethylene film having a thickness
of between
about 2-7 mils and preferably about 6 mils. Coated upon the surface of the
supporting layer 18
which is not in contact with the upper surface 14 of the asphalt layer 12 is
the traction layer 20
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which comprises a polyurethane material having a mineral grit 22 embedded
therein. As noted
previously, other materials sucli as epoxy, polyester, polypropylene,
varnishes and the like may
be substituted for the polyurethane. The grit provides the traction layer 20
with an exposed
surface 30 having a roughness sufficient to effect a mechanical interference,
and thereby gripping
effect, with the sole of a boot or shoe being worn by a roofing installer. As
such, the likelihood
of an installer falling from the roof as a result of slipping on the membrane
surface is
significantly reduced.
The release layer 24 is typically a paper sheet having a siliconized surface
26. As an
alternative, the release layer can comprise two separate sheets; a first
supporting sheet of a paper
or polymeric film, and a second sheet of a low surface energy material.
Additionally, in the case
of a siliconized paper, the silicon coating may be replaced by some other
suitable low surface
energy material such as a wax emulsion or a soap solution.
The finished weight of a roll of the material described above is typically
about 25 pounds
(about 11.4 kg). One roll is defined as 108 square feet of material (10.04
m2). This amount of
material typically is used to cover a approximately 100 square feet (9.29 mZ)
of roof surface. The
thickness of the finished membrane, less the release sheet, is between about
40 mils and about 60
mils. Rolls typically are about 36 inches (91.44 cm) wide and about 36 feet
(10.97 m) long. It
should be noted that although various dimensions are presented herein, they
are intended as
examples only and, as such, should not be considered to be limiting unless
expressly set out in
the appended claims.
FIGS. 3 and 4 show the manner in which the membrane material 10 is intended
for use on
a roof deck 36 in the region of the roof eaves 38. In applying the present
invention, eaves
flashing is replaced by the membrane 10 described herein. In use, the release
sheet 24 is
removed from the lower surface 16 of the asphalt layer 12, and the membrane 10
is secured to the
roof deck 36 by adhesive action and/or nails. The membrane 10 is positioned
along the leading
edge of the roof. Subsequently, a first row of shingles 42 is positioned in an
overlying
relationship to the membrane 10. The shingles are secured in place using nails
40. Although the
roofing installer will often be caused to stand on the membrane during
installation of the
shingles, the traction layer 20 of the inventive membrane 10 provides
sufficient friction to
minimize the likelihood of slipping. Thus, as compared to many of the known
roofing
membranes, the membranes of the present invention provide a safer work
surface.
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Equivalents
From the foregoing detailed description of the specific embodiments of the
invention, it
should be apparent that a unique roofing membrane material has been described.
Although
particular embodiments have been disclosed herein in detail, this has been
done by way of
exatnple for purposes of illustration only, and is not intended to be limiting
with respect to the
scope of the appended claims whicli follow. In particular, it is contemplated
by the inventor that
various substitutions, alterations, and modifications may be made to the
invention without
departing from the spirit and scope of the invention as defined by the claims.
