Note: Descriptions are shown in the official language in which they were submitted.
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ROOFING SHINGLE SYSTEM AND SHINGLES FOR USE THEREIN
SPECIFICATION
FIELD OF THE INVENTION
[0001] This invention relates to an improved roofing shingle and a roofing
system
that utilizes the shingles. In particular, the invention relates to the
construction of roofing
shingles featuring unique dimensions that minimize the amount of material
required to make
the shingles and a roofing system that utilizes the shingles.
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BACKGROUND OF THE INVENTION
[0002] Roofing products are often divided into three broad groups:
shingles, roll
roofing, and underlayment. Shingles and roll roofing typically function as
outer roof
coverings designed to withstand exposure to weather and the elements.
Typically, the
underlayment is first laid on the roof deck, and then the outer roofing
covering (e.g., shingles
or roll roofing) is installed on top of the underlayment.
[0003] Asphalt shingles are the most commonly used roofing materials.
Shingles and
roll roofing generally contain the same basic components, which provide
protection and long
term wear associated with asphalt roofing products. These components include a
base
substrate material made from an organic felt or fiberglass mat which serves as
a matrix to
support the other components and gives the product the required strength to
withstand
manufacturing, handling, installation, and service in the intended
environment. An asphalt
coating formulated for the particular service application is often applied to
the base substrate
material to provide the desired long-term ability to resist weathering and to
provide stability
under the anticipated temperature extremes. An outer layer of mineral granules
is also
commonly applied to the asphalt coating to form a surface exposed to the
weather which
shields the asphalt coating from the sun's rays, adds color to the final
product and provides
fire resistance.
[0004] Typically, shingles are installed on a roof deck such that the
shingles are in a
row from left to right and the lateral edges of the shingles in the row are
contiguous with each
other so as to abut each other, i.e. their lateral edges are adjacent to one
another. Each row
represents a course and the shingles are applied in overlapping courses on the
roof deck,
wherein the buttlap portion of a subsequent course is placed on the headlap
portion of a
previous course. The headlap portion of a conventional shingle is at least as
wide as the
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buttlap portion of the shingle so that when the shingles are installed on a
roof deck in
overlapping courses, the entire buttlap portion of a subsequent course has
headlap beneath it.
If the shingle has tabs and openings in the buttlap portion, it is typical
that at least two inches
of the headlap portion of the subsequent course also has headlap from the
previous course of
shingles beneath it. This manner of installation prevents leakage to the roof
deck where the
lateral edges of the shingles abut each other and, in the case of tab
shingles, where the
openings in the buttlap are located.
[0005] In a typical prior art roofing system, contiguous shingles in a row
abut each
other at their lateral edges. Thus, when the shingles are exposed to wet
weather, it is possible
that leakage can occur at the region where the shingles abut. To prevent that,
overlapping
subsequent rows of shingles are installed in an offset pattern and each
shingle's headlap
portion is at least as wide as the buttlap portion. Thus, when the shingles
are applied to the
roof in a plurality of courses and the buttlap portion of a second course of
shingles is laid
over the headlap portion of a first row of shingles there is always headlap
present underneath
the regions where the contiguous shingles in a row abut. Any water penetrating
the places
where lateral edges of shingles abut contacts the headlap rather than the roof
deck.
[0006] In a typical prior art roofing system using shingles with a tabbed
buttlap
portion, overlapping courses of shingles are installed such that they
generally overlap each
other to provide at least two inches of headlap across the entire headlap from
the previous
course of shingles underneath the headlap portion of the subsequent course.
Such headlap
overlap helps ensure that water contacting the headlap through the openings in
the subsequent
course does not contact the roof deck. Such headlap overlap is also usually
required by
building code.
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[0007] As energy costs rise, the cost of petroleum-based materials, such as
asphalt,
and transportation expenses often rise as well. The amount of material
employed in a shingle
can contribute to costs of the shingle and the overall weight of the shingle,
which also affects
transportation costs. Certain installation requirements, such as a two inch
headlap overlap for
single layer shingles with a tabbed buttlap portion, constrain the possible
dimensions for a
shingle. Decreasing the amount of asphalt, substrate, and other materials
required to make a
shingle while maintaining the equivalent performance and coverage area, can
reduce both
material costs and transportation expenses to deliver such shingles.
[0008] Various shingles have employed, for aesthetic purposes, non-straight
edge
contours. U.S. Pat. No. 1,345,627 describes single layer roofing shingles to
be arranged in
overlapping courses. The shingle may have non-straight longitudinal edge
contours, which
shadow each other on either side of the shingle such that the width of the
shingle is constant
across the length of the shingle. The contour of the shingle, along with other
features,
operates to optically simulate various appearances including curved tiles.
[0009] U.S. Pat. No. 2,272,032 describes single layer asphalt roofing
shingles with
varying cross-sectional thickness to be arranged in offset overlapping
courses. The shingle
has longitudinal zigzag edge contours, which shadow each other on either side
of the shingle
such that the width of the shingle is constant across the length of the
shingle. When the
courses are installed, the thicker portions of a subsequent shingle "nest" in
the thinner
portions of the previously installed shingle to provide the protection
qualities of more heavily
coated roofing material.
[00010] U.S. Pat. No. 4,274,243 describes a laminated asphalt roofing
shingle to be
arranged in overlapping courses to optically simulate tiles. The shingle has a
headlap portion
with a generally straight edge and a butt portion with a generally
continuously curving
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sinuous butt edge and an underlay portion with a matching generally
continuously curving
sinuous butt edge.
[000111 U.S. Pat. No. 4,333,279 describes strip or tabbed single layer
asphalt shingles.
The shingles have a headlap portion with a generally straight edge and a butt
portion with a
jagged, nonuniform butt edge.
[00012] U.S. Pat. No. 5,939,169 describes a composite shingle with a
headlap portion,
a buttlap portion that is divided into uniformly spaced apart tabs with curved
or straight
bottom edges or crimped corners, and an elongated backup strip that underlays
the buttlap
portion and conforms in outline to the bottom edge of the tabs and extends
below the tabs at a
distance equal to the spaces between the tabs so as to form a uniform border
around the tabs.
[00013] U.S. Pat. No. 6,058,670 describes a laminated shingle with a
headlap portion,
a buttlap portion that is divided into uniformly spaced apart tabs with curved
or straight
bottom edges or crimped corners, and an elongated top strip that overlays the
headlap portion
and has a lower edge that duplicates or mirrors the sequence of the lower edge
of the tab so as
to allow a uniform strip border surrounding each tab upon installation.
[00014] U.S. Pat. No. 6,698,151 describes a laminated asphalt roofing
shingle to be
arranged in overlapping courses to simulate tiles. The shingle has a headlap
portion with a
generally straight contour and a buttlap portion with tabs. The tabs and
openings between the
tabs may have generally curved bottom edges. The buttlap portion also includes
an underlay
portion, which may have generally curved edges that may be coextensive with
the curved
bottom edges of the tabs.
[00015]
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SUMMARY OF THE INVENTION
[00016] In accordance with the present invention, a roofing system is
provided having
a multiplicity of courses of tabbed roofing shingles wherein the shingles have
non-straight
longitudinal edges on either side of the shingle such that the width of the
shingle varies across
the length of the shingle.
[00017] The shingles of the present invention are single layer and have a
maximum
width (w) and a length (/), as illustrated in FIG. 2. The shingles further
comprise a headlap
portion and a buttlap portion, each having a non-straight longitudinal edge
contour, as
illustrated in FIGS. 2 and 9. The non-straight longitudinal edges comprise
peaks and valleys
with the distance between a peak and valley defining the edge magnitude 20 of
the non-
straight longitudinal edge, as illustrated in FIG. 2. The buttlap portion
extends from the
headlap portion and comprises tabs separated by openings, as illustrated in
FIG. 2 featuring
tabs 15 and openings 16.
[00018] When the shingles of the present invention are installed on a roof
deck, a
portion of the headlap portion of a shingle in a subsequently installed course
overlaps a
portion of the headlap portion of a shingle in a previously installed course
to provide a
headlap overlap region. The width dimension of the headlap overlap region
varies due to the
non-straight longitudinal edge of the previously installed shingle. In a
preferred embodiment,
the shingles are installed such that the maximum headlap overlap dimension is
beneath the
headlap portion of the subsequently installed shingle laterally proximate the
openings in the
buttlap portion of the shingle, as illustrated in FIG. 4, featuring maximum
headlap overlap
dimension 41.
[00019] The width dimensions of the shingles operate to provide sufficient
headlap
overlap laterally proximate the openings in the buttlap portion of the
subsequently installed
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shingle while reducing the material required to make the shingles by reducing
the headlap
overlap not laterally proximate the openings in the buttlap portion of the
subsequently
installed shingle.
[00020] Thus, in accordance with one aspect of the present invention, a
roofing system
is provided comprising roofing shingles having headlap portions with non-
straight
longitudinal edges and a buttlap portions with non-straight longitudinal edges
The roofing
system comprises a plurality of courses. Each course is comprised of a
plurality of shingles
wherein the dimensions of the shingles operate to provide sufficient headlap
overlap laterally
proximate the openings in the buttlap portion of subsequently installed
shingles while
reducing the material required to make the shingle by minimizing the headlap
overlap not
laterally proximate the openings in the buttlap portion of subsequently
installed shingles. The
headlap overlap underneath the headlap portion of the subsequent course,
illustrated e.g. by
maximum headlap overlap dimension 41 in FIG. 4, laterally proximate the
openings in the
buttlap portion, defines a maximum headlap overlap dimension. In a preferred
embodiment,
the maximum headlap overlap dimension is about two inches.
[00021] In a further preferred embodiment, the non-straight longitudinal
edges are
sinuously curved, e.g., as illustrated in FIG. 2. In another preferred
embodiment, the non-
straight longitudinal edges are angular such that generally straight lines
connect the peaks and
valleys of the edge contour, e.g., as illustrated in FIG. 9. In another
preferred embodiment,
the contours of the non-straight longitudinal edges have the same uniform
pattern. In another
preferred embodiment, the uniform non-straight longitudinal edges do not
shadow each other
laterally across the shingle. In a particularly preferred embodiment, the
uniform non-straight
longitudinal edges of the shingle mirror each other laterally across the
shingle such that the
distance between a buttlap peak and a corresponding headlap peak located
directly across
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said shingle from the buttlap peak defines a maximum width of the shingle. In
another
preferred embodiment, the uniform non-straight longitudinal edges of the
shingle may be
offset from each other such that they do not shadow each other or mirror each
other laterally
across the shingle. In a preferred embodiment, the edge magnitude 20, as
illustrated in FIG.
2, is from about 1% to about 12.5% the maximum width of the shingle (w). In a
particularly
preferred embodiment, the edge magnitude 20 is about 2.1% the maximum width of
the
shingle (w).
[00022] In a further preferred embodiment, the amount of material required
to make
shingles from a sheet of roofing material is reduced by cutting the sheet of
roofing material
longitudinally along non-straight lines wherein the formed shingles have a
cumulative
maximum combined width that is greater than the width of the sheet of roofing
material.
[00023] The shingles of the invention are improvements of roofing shingle
materials
known in the art, where the improvements include a headlap edge and the
buttlap edge, which
are generally non-straight and when installed on a roof deck the maximum
headlap overlap
dimension is beneath the headlap portion of the subsequently installed shingle
laterally
proximate the openings in the buttlap portion of the subsequently installed
shingle.
DETAILED DESCRIPTION OF THE FIGURES
[00024] For a more complete understanding of the present invention, and the
advantages thereof, reference is now made to the following descriptions taken
in conjunction
with the accompanying figures but which are not to be construed as limiting to
the scope of
the present invention as defined by the appended claims, in which:
[00025] FIG. 1 shows a prior art single layer roofing shingle;
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[00026] FIG. 2 shows an exemplary embodiment of a single layer roofing
shingle of
the present invention having a curved contour in the butt portion and a curved
contour in the
headlap portion;
[00027] FIG. 3 shows a roofing system incorporating the shingles of FIG. 1;
[00028] FIG. 4 shows an exemplary embodiment of a roofing system of the
present
invention incorporating the shingles of FIG. 2;
[00029] FIG. 5 shows a sheet of roofing material from which components for
four
single layer shingles of FIG. 1 may be obtained.
[00030] FIG. 6 shows an exemplary sheet of roofing material of the present
invention
from which components for two single layer shingles of FIG. 2 may be obtained,
and two
shingles with generally straight longitudinal headlap edges may be obtained.
[00031] FIG. 7 show a sheet of roofing material from which components for
three
single layer shingles of FIG. 1 may be obtained.
[00032] FIG. 8 shows an exemplary sheet of roofing material of the present
invention
from which components for one single layer shingle of FIG. 2 may be obtained,
and two
shingles with generally straight longitudinal headlap edges may be obtained.
[00033] FIG. 9 shows an exemplary embodiment of a single layer shingle of
the
present invention having non-straight longitudinal edge contours that are
angular such that
generally straight lines connect peaks and valleys in the edge contours.
DETAILED DESCRIPTION
[00034] The preferred embodiments of the present invention and its
advantages are
best understood by referring to FIGS. 1 through 9, like numerals being used
for like and
corresponding parts of the various drawings.
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[00035] FIG. 1 represents a typical prior art roofing shingle 7 comprising
a headlap
portion 1 and a buttlap portion 2. The buttlap portion 2 comprises tabs 5
separated by
openings 6. The shingle has a width (w) and a length (/) and comprises
generally straight
longitudinal edges 3, 4 and generally straight lateral edges 8, 9.
[00036] A shingle 17 incorporating one embodiment of the present invention
is shown
in FIGs. 2, 4, 6, 8 and 9. Shingle 17 preferably comprises a headlap portion
11 and a buttlap
portion 12. The buttlap portion 12 comprises tabs 15 separated by openings 16.
The shingles
have a maximum width (w) and a length (/) and comprise a non-straight
longitudinal headlap
edge 14, a non-straight longitudinal buttlap edge 13 and generally straight
lateral edges 18,
19. The non-straight longitudinal headlap edge 14 defines headlap peaks 23
extending away
from the longitudinal center of the shingle and headlap valleys 24 extending
toward the
longitudinal center of the shingle. The non-straight longitudinal buttlap edge
13 defines
buttlap peaks 21 extending away from the longitudinal center of the shingle
and buttlap
valleys 22 extending toward the longitudinal center of the shingle. The
distance between
buttlap peak 21 and buttlap valley 22, as well as the distance between headlap
peak 23 and
headlap valley 24, defines the edge magnitude 20. The tabs 15 have a uniform
longitudinal
tab dimension 204 and a maximum tab width dimension 202 located at the
longitudinal center
of the tab 15, or at half of the longitudinal tab dimension 203. The buttlap
peaks 21 are
approximately located at the longitudinal center of the tabs 15. The buttlap
valleys 22 are
approximately located at the openings 16. The openings 16 have a uniform
longitudinal
dimension 201. It should be understood that the shingle of the invention is
not limited to
shingles with three tabs in the buttlap portion, and that shingles with two or
more tabs are
contemplated. For example, shingles with two tabs through ten tabs utilizing
the principles
underlying the present invention are within the scope of the present
invention.
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[00037] FIG. 3 shows a roofing system wherein prior art shingles 33, 34, 35
are
installed as they would be applied to a roof deck. Part of the headlap portion
1 lies beneath
part of the buttlap portion 2 of a subsequent course. The system is comprised
of shingles
installed as they would be in an offset manner in three separate courses.
After a shingle 33 in
a first course is installed, a shingle 34 in a subsequent course is applied to
the roof deck such
that the buttlap portion 2 of the subsequent shingle 34 overlaps the headlap
portion 1 of the
shingle 33 in the previous course. The buttlap portion 2 of each shingle is
exposed to the
weather defining a buttlap exposure dimension 32. A portion of the headlap
portion 1 of a
shingle from a subsequently installed course of shingles also overlaps at
least a portion of the
headlap portion 1 of a shingle from a previously installed course of shingles
defining a
continuous headlap overlap region 31 of uniform width across the shingle, as
illustrated in
FIG. 3 for the headlap overlap of shingles 34, 35.
[00038] FIG. 4 shows a roofing system of the invention wherein shingles 43,
44, 45 of
the invention are installed as they would be applied to a roof deck. A part of
the headlap
portion 11 lies beneath part of the buttlap portion 12. The system is
comprised of shingles
installed as they would be in an offset manner in three separate courses.
After a shingle 43 in
a first course is installed, a shingle 44 in a subsequent course is applied to
the roof deck such
that the buttlap portion 12 of the subsequent shingle 44 overlaps the headlap
portion 11 of the
shingle 43 in the previous course. The buttlap portion 12 of each shingle is
exposed to the
weather defining a buttlap exposure dimension 42, which is equivalent in width
to the
maximum tab width dimension 202 illustrated in FIG. 2. A portion of the
headlap portion 11
of a shingle from a subsequently installed course of shingles also overlaps at
least a portion of
the headlap portion 11 of a shingle from a previously installed course of
shingles defining a
headlap overlap region having a maximum headlap overlap dimension 41, which is
laterally
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proximate the openings 16 in the buttlap portion 12 of a shingle from a
subsequently installed
course of shingles, as illustrated in FIG. 4 for the headlap overlap of
shingles 44, 45.
[00039] Referring to FIG. 2, the exposed outer surface or weather surface,
i.e., the
buttlap portion 12 of shingle 17 of the invention, may be coated with various
types of mineral
granules to protect the asphalt coating, to add color to shingle 17 of the
invention and to
provide fire resistance. For some applications, ceramic-coated mineral
granules may be
disposed on the top surface of the buttlap portion 12. Also, a wide range of
mineral colors
from white and black to various shades of red, green, brown and any
combination thereof
may be used to provide a roof having the desired color for shingle 17 of the
invention. In
other embodiments, the entire outer surface of shingle 17 of the invention may
be coated with
any of the aforementioned coatings. In further embodiments, the headlap
portion 11 of
shingle 17 of the invention may be coated with coatings that contrast with
coatings applied to
the buttlap portion 12 of shingle 17 of the invention. The underside of
shingle 17 of the
invention may be coated with various inert minerals with sufficient
consistency to seal the
asphalt coating.
[00040] For one embodiment of the present invention, the shingle 17 may be
formed
from a fiberglass mat (not shown) with an asphalt coating on both sides of the
mat, or a
partial coating by coating the headlap portion only or the buttlap portion
only. If desired, the
present invention may also be used with shingles formed from organic felt or
other types of
base material, including but not limited to synthetic mats or synthetic
glass/hybrid mats
having an appropriate coating. Nonlimiting embodiments of coatings include
asphalt and
modified bituminous coatings based on atactic polypropylene (APP), styrene-
butadiane-
styrene (SBS), styrene-ethylene-butadiene-styrene (SEBS), amorphous polyalpha
olefin
(APAO), thermoplastic polyolefin (TP0), synthetic rubber or other asphaltic
modifiers.
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[00041] An important feature of the present invention includes providing a
shingle
with a non-straight longitudinal headlap edge and non-straight longitudinal
buttlap edge. The
dimensions of the inventive shingles operate to provide sufficient headlap
overlap laterally
proximate the openings in the buttlap portion of the subsequently installed
shingle while
reducing the material required to make the shingles. Such material reduction
is accomplished
by reducing the headlap overlap which is not laterally proximate the openings
in the buttlap
portion of the subsequently installed shingle. In a preferred embodiment, the
non-straight
longitudinal headlap edge and the non-straight longitudinal buttlap edge have
the same
uniform pattern and mirror each other laterally across the shingle, as
illustrated in FIG. 2
where headlap peak 23 mirrors buttlap peak 21 and headlap valley 24 mirrors
buttlap valley
22. For a particularly preferred embodiment of the present invention shown in
FIGS. 2, 4, 6,
and 8, the edge magnitude 20 is 0.25 inches or 2.1% of the maximum width (w)
of the
shingle. The maximum width (w) of the shingle is about twelve inches and the
shingle length
(/) is about 36 inches. The butt portion 12 comprises three tabs 15 with a
maximum tab width
dimension 202 of about five inches, and a longitudinal tab dimension 204 of
about 11.75
inches, and spaced apart by openings 16 having a longitudinal opening
dimension 201 of
about 0.25 inches. The non-straight longitudinal headlap edge 14 and non-
straight
longitudinal buttlap edge 13 have uniform sinuously curved contours. It should
be
understood that the above examples are illustrative, and that patterns and
dimensions other
than those described above can be used while utilizing the principles
underlying the present
invention.
[00042] Depending on the desired application and appearance of each shingle
17, the
edge magnitude 20 may be from about 0.125 inches to about 1.5 inches, or from
about 1% to
about 12.5% of the maximum width of the shingle (w), as long as the shingle
when applied to
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a roof deck in an overlapping roofing system maintains a maximum headlap
overlap
dimension 41 of about two inches, which is laterally proximate the openings in
the buttlap
portion of the subsequently installed shingle. In a particularly preferred
embodiment the
maximum headlap overlap dimension is about two inches or the minimum headlap
dimension
overlap required by the applicable building code. In a preferred embodiment,
the overlapping
subsequently installed courses of shingles are installed in an offset pattern.
The non-straight
longitudinal headlap edge 14 and non-straight longitudinal buttlap edge 13 may
have a
uniform angular or zigzag pattern (see FIG. 9 showing shingle 90 of the
invention featuring
longitudinal edges with a zigzag pattern 91), as long as the pattern of the
headlap edge 14
does not shadow the pattern of the buttlap edge 13. In a particularly
preferred embodiment,
the non-straight longitudinal headlap edge 14 is the mirror image of the non-
straight
longitudinal buttlap edge 13 such that headlap peaks 23 correspond to buttlap
peaks 21 on the
other side of the shingle 17, and headlap valleys 24 correspond to buttlap
valleys 22 on the
other side of the shingle 17.
[00043] In another embodiment, the shingle dimensions have a maximum width
(w)
such that when installed in an overlapping roofing system the maximum width
(w) of the
preceding shingle is located underneath the openings 16 in the buttlap portion
12 of the
subsequent shingle.
[00044] FIG. 5 shows a sheet of roofing material 51 with a width 52 from
which four
prior art shingles 7 are made by cutting the roofing material 51
longitudinally along generally
straight lines 53a, 53b, 53c. The cuts form the generally straight
longitudinal edges 3, 4 of
the prior art shingle 7, as illustrated in FIG. 1. Slits 55 of a width 56 are
cut into the roofing
material 51 to form the openings 6 that separate the tabs 5 in the buttlap
portion 2 of the prior
art shingle 7, as illustrated in FIG. 1.
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[00045] FIG. 6 shows a sheet of roofing material 61 of the invention with a
width 62
from which two shingles 68a and 68b of the invention are made by cutting the
roofing
material 61 longitudinally along non-straight lines 63a, 63b, 63c. The cuts
form the non-
straight longitudinal headlap edge 14 and the non-straight longitudinal
buttlap edge 13 of the
shingle 17 of the invention, as illustrated in FIG. 2. Slits 65 of a width 66
are cut into the
roofing material 61 to form the openings 16 that separate the tabs 15 in the
buttlap portion 12
of the shingle 17 of the invention, as illustrated in FIG. 2. Shingles 68a and
68b are
equivalent to shingle 17 of the invention, as illustrated in FIG. 2, and
shingles 67a and 67b
each form a shingle having a non-straight longitudinal buttlap edge and a
generally straight
longitudinal headlap edge. All of which may be used as shingles in the roofing
system of the
invention.
[00046] FIG. 7 shows a sheet of roofing material 71 with a width 72 from
which three
prior art shingles 7 are made by cutting the roofing material 71
longitudinally along generally
straight lines 73, 74. The cuts form the generally straight longitudinal edges
3, 4 of the prior
art shingle 7, as illustrated in FIG. 1. Slits 75 of a width 76 are cut into
the roofing material
71 to form the openings 6 that separate the tabs 5 in the buttlap portion 2 of
the prior art
shingle 7, as illustrated in FIG. 1.
[00047] FIG. 8 shows a sheet of roofing material 81 of the invention with a
width 82
from which one shingle 88 of the invention is made by cutting the roofing
material 81
longitudinally along non-straight lines 83, 84. The cuts form the non-straight
longitudinal
headlap edge 14 and the non-straight longitudinal buttlap edge 13 of the
shingle 17 of the
invention, as illustrated in FIG. 2. Slits 85 of a width 86 are cut into the
roofing material 81
to form the openings 16 that separate the tabs 15 in the buttlap portion 12 of
the shingle 17 of
the invention, as illustrated in FIG. 2. Shingle 88 is equivalent to shingle
17 of the invention,
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as illustrated in FIG. 2, and shingles 87a, 87b each form a shingle having a
non-straight
longitudinal buttlap edge and a generally straight longitudinal headlap edge.
All of which
may be used as shingles in the roofing system of the invention.
[00048] An important feature of the invention is reducing the amount of
material
required to make shingles from a sheet of roofing material by cutting the
sheet of roofing
material with non-straight longitudinal cuts wherein the formed shingles have
a cumulative
maximum combined width that is greater than the width of the sheet of roofing
material. The
width 62, 82 of the roofing material 61, 81 required to make shingles in the
manner of the
invention by cutting the roofing material 61, 81 in non-straight longitudinal
lines 63a, 63b,
63c, 83, 84 is less than the width 52, 72 of the roofing material 51, 71
required to make prior
art shingle 7. For one embodiment of the present invention, the width 62 of
roofing material
61 required to make four shingles with at least a portion of each shingle
having a width of
about twelve inches is about 47.25 inches. The width 52 of roofing material 51
required to
make four prior art shingles 7 with a width (w) of twelve inches is 48 inches.
For another
embodiment of the present invention, the width 82 of roofing material 81
required to make
three shingles with at least a portion of each shingle having width of about
twelve inches is
about 35.5 inches. Forming the prior art shingle 7 according to conventional
methods
requires a wider sheet of roofing material. The width 72 of roofing material
71 required to
make three prior art shingles 7 with a width (w) of twelve inches is 36
inches.
[00049] The non-straight longitudinal edges of the shingle of the present
invention are
desirable because they allow for a reduction in the weight of the shingles of
the invention, as
well as a reduction in the amount and cost of the materials used to make the
shingles and the
expense to transport them. A roofing system of the invention using the shingle
17 or 90 of
the present invention with non-straight longitudinal edges covers the same
surface area of
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CA 02821561 2013-06-12
WO 2013/095710
PCT/US2012/043889
roof deck as a roofing system using prior art shingles with generally straight
longitudinal
edges while using less material because the dimensions of the shingle 17 or 90
of the
invention maintain a maximum headlap overlap dimension 41 of about two inches,
or the
minimum headlap overlap required by the applicable building code, by
dispensing with extra
material otherwise required to construct a shingle with generally straight
edges and larger
surface area. In a particularly preferred embodiment, about 50% of the
shingles used in a
roofing system of the present invention comprises shingle 17 or 90 of the
invention. In
another particularly preferred embodiment, about 33% of the shingles used in a
roofing
system of the present invention comprises shingle 17 or 90 of the invention.
[00050] Although the present invention and its advantages have been
described in
detail, it should be understood that various changes, substitutions and
alterations can be made
therein without departing from the spirit and scope of the invention as
defined by the
appended claims.
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