Patent Application
20080155923
This invention relates to roofing materials. More particularly, the invention pertains to a roofing underlayment for use underneath roofing shingles that do not have a traditional headlap portion.
This invention relates generally to roofing materials, and more particularly to an underlayment material for a roofing shingle system. Most known roofing shingle products are traditionally comprised of a headlap portion and a buttlap portion. The headlap portion of the roofing shingle provides part of the weather resistance of the roofing shingle, such as water and wind resistance, as well as other weathering characteristics. Traditionally, the headlap portion accounts for over fifty percent of the vertical width of the roofing shingle. In an effort to reduce manufacturing and delivery costs as well as to ease installation of the roofing shingles, alternate headlap construction roofing shingle configurations have emerged into the marketplace. Several examples of such alternate headlap construction roofing shingle configurations can be found in U.S. Pat. No. 6,990,779, the disclosure of which is herein incorporated by reference in its entirety. In order to maintain acceptable weathering characteristics of such alternate headlap construction roofing shingles, it is necessary to install an intermediate layer between the roof deck and the roofing shingle to replace the traditional headlap portion of the shingle. Several of such intermediary layers are known, such as the interply layer disclosed in U.S. Pat. No. 6,990,779 incorporated above. However, such intermediary layers often significantly increase the complexity of the installation of the alternate headlap construction shingles, as well as create a potential for compromised wind and waterproofing performance. Hence, there is a need for an improved intermediary layer for use roofing shingles having alternative headlap portion constructions.
This invention relates to an underlayment for use under a plurality of courses of roofing shingles. The underlayment includes a water impermeable membrane layer. The membrane layer preferably contains at least one flap extending horizontally across the membrane layer. The flap is preferably movable between a flat position and a raised position. In the raised position, an upper edge of a roofing shingle can be positioned under the flap such that the upper edge of the roofing shingle can be subsequently overlapped by the flap when the flap is moved into the flat position. The flap can then preferably be subsequently overlapped by another course of roofing shingles.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
Referring now to the drawings, there is illustrated in
The first shingle sheet 12 and second shingle sheet 14 can be made from any suitable materials, such as asphalt coated fiberglass mat. It will be appreciated that the shingle sheets 12 and 14 may also be made from any other suitable materials, such as organic felt or other types of base material. Accordingly, the present invention is not limited to use with shingles including a fiberglass mat. The shingle sheets 12 and 14 can be adhered together by any suitable means, such as by gluing the second shingle sheet 14 to the underside of the first shingle sheet 12. In the illustrated embodiment, the first shingle sheet 12 has a greater vertical width than the second shingle sheet 14, which creates a single ply nailing zone 12c within the headlap portion 12a of the first shingle sheet 12. The first and second single sheets 12, 14 may also have the same vertical width, resulting in a multiple layer nailing zone (not shown) in the headlap portion 12a as well. It will also be appreciated that the nailing zone 12c can account for any suitable portion of the headlap portion 12a, and that the nailing zone 12c can be located at any suitable point within the headlap portion 12a as well. The headlap portion 12a can also contain an adhesive strip (not shown) along the uppermost edge of the headlap portion 12a, although such is not required. The adhesive strip can be used for positioning and securing the roofing shingle 10. The resulting laminated shingle 10 preferably has a generally rectangular configuration, although it will be appreciated that the shingle 10 may be any other suitable shape as well.
The laminated shingle 10 has a reduced headlap portion 12a relative to traditional roofing shingle designs. Preferably, the vertical width of the headlap portion 12a accounts for an amount within the range of from about 10 percent to about 45 percent of the overall vertical width of the roofing shingle 10. More preferably, the vertical width of the headlap portion 12a accounts for an amount within the range of from about 20 percent to about 40 percent of the overall vertical width of the roofing shingle 10. Accordingly, the buttlap portion 12b of the shingle 10 preferably accounts for an amount within the range of from about 55 percent to about 90 percent, and more preferably for an amount within the range of from about 60 percent to about 80 percent, of the overall vertical width of the roofing shingle 10. The shingle 10 may have any suitable dimensions, with the headlap portion 12a and the buttlap portion 12b correspondingly apportioned as described above. For example, a shingle having the dimensions of 13.25 inches in vertical width and 36 inches in horizontal length would preferably have a buttlap portion 12b within the range of from about 7.29 inches in vertical width to about 11.93 inches in vertical width, and more preferably would have a buttlap portion 12b within the range of from about 7.95 inches in vertical width to about 10.60 inches in vertical width. Additionally, a shingle may include an entire headlap region and/or nail zone in the headlap comprising a reinforcement as described in copending U.S. patent application Ser. No. 11/198,522, which is incorporated herein by reference in its entirety.
As discussed above, the laminated roofing shingle 10 described above is one of many environments in which the underlayment of the present invention may be used. Another example of a roofing shingle with which the underlayment of the present invention can be used includes a strip type of shingle with an alternate headlap construction. The strip shingle may be a single layer shingle, or it may also contain multiple layers of roofing material. Both the single layer and multiple layer strip shingle configurations may contain cutout portions, such as the cutout configuration described above, although such is not required.
A preferred underlayment 20 may include a base layer 22, although such is not required. The base layer 22 can be formed from any suitable weather resistant material or combination of materials. Examples of such suitable materials include, but are not limited to, asphalt based materials, polymer materials, foil sheet, fiber reinforcements, mesh, mat, scrim, fabric, filler, fire retardant, or mineral materials. The base layer 22 may have a layer of adhesive material applied to the back side thereof for applying the underlayment 20 to the roof deck 13 or a layer of roof felt or other base material, although such is not required. Where adhesive is applied to the base layer 22, any adhesive material suitable for joining the underlayment 20 to the roof deck 13 or base material may be used. An adhesive layer 24 is then preferably applied over the base layer 22, although such is not required. The adhesive material used for the adhesive layer 24 can be any suitable adhesive for securely joining the layers of the underlayment 20 together, such as water based acrylic adhesives, solvent based adhesives, asphalt based adhesives, or thermoresin materials. A reinforcing material may be positioned over the adhesive material of the adhesive layer 24 as well, although such is not required. The reinforcing material is preferably a mat, mesh, or scrim of glass fiber or polymer fiber, although any suitable reinforcing material and reinforcing material configuration, such as discontinuous fibers, may also be used. The reinforcing material is preferably configured such that there are open spaces amongst the reinforcing materials that allow the adhesive material of the adhesive layer 24 to fill and flow through the spaces and adhere the various layers of the underlayment 20 to one another. It will be appreciated that the adhesive layer 24 can contain additional materials or have other suitable configurations as well, such as including fire retardant and/or other filler material. These additional materials may be incorporated into the adhesive material of the adhesive layer 24, or may be separately applied over the base layer 22. Examples of such additional materials include, but are not limited to, materials containing aluminum hydroxide, borates, phosphates, carbonates, or any other fire retardant or filler material.
A membrane layer 26 is preferably applied over the base layer 22 and adhesive layer 24. The membrane layer 26 contains a series of flaps 28 that extend horizontally across the membrane layer 26. The flaps 28 are preferably integrally formed into the membrane layer 26, although it will be appreciated that the flaps may also be separately formed and attached to the membrane layer 26 by any suitable means. The flaps 28 may be formed in any suitable manner, and are preferably formed as a series of horizontally extending pleats on the membrane layer 26. As best shown in
A membrane layer 36 is applied over the base layer 32 and adhesive layer 34. The membrane layer 36 contains a series of integrally formed flaps 38 that extend horizontally across the membrane layer 36. In this embodiment, the membrane layer 30 is formed from strips of membrane material that are permanently joined together such that vertically adjacent strips of the membrane material are arranged in a partially overlapping relationship to form the flaps 38 on the membrane layer 36. An adhesive material 40 is used to permanently join the strips of membrane material together to form the membrane layer 36. Any suitable type of adhesive material 40 may be used. Examples of such suitable adhesive materials include, but are not limited to water based acrylic adhesives, solvent based adhesives, asphalt based adhesives, or thermoresin materials.
When the flaps 38 are in the raised position, the upper edge of a course of roofing shingles 10 can be positioned and fastened to the portion of the underlayment 30 that is subsequently overlapped by the flaps 38 when the flaps 38 are moved into the flat position. The function of the underlayment 30 will be discussed in greater detail below. The flaps 38 may have any suitable dimensions. Preferably, the flaps 38 extend across the entire horizontal length of the underlayment 30, although such is not required. The flaps 38 may be of any suitable width for covering the upper edge of the courses of roofing shingles placed underneath the flap 38, as discussed above. Preferably, the width of the flaps 38 is within the range of from about ½ inch to about 3 inches wide. The flaps 38 may also have a sealing tape or other suitable adhesive material applied to the underside thereof for further securing the roofing shingles 10 underneath the flaps 38, although such is not required. The flaps 38 may also include an adhesive material on the top surface thereof for securing a subsequent layer of roofing shingles to the underlayment 30, although such is not required. The membrane layer 36 can be formed from any suitable water impermeable material, including but not limited to synthetic polymers, elastomers, bitumen, polymer-modified bitumen, metal foils, and coated fabric.
In addition to providing superior waterproofing and other weathering characteristics to a completed roofing system, the underlayment 20 of the present invention also provides another specific advantage in that the underlayment 20 can be exposed without shingles 10 for both short and extended periods of time. In the short term, this feature is particularly advantageous both during installation of the roofing system as well as in the event of a disaster that may cause the roof to be damaged. Because the underlayment 20 is made from water impermeable, weather durable materials, exposure of the underlayment 20 for short periods of time without shingles will not compromise the integrity of the roof by permitting water onto the roof deck material. Long term exposure of the underlayment 20 is also feasible. One example of long term exposure of underlayment 20 is a roofing system where a portion of the flap 28 is exposed to provide spacing between two adjacent courses of roofing shingles 10 to produce a “thick looking” effect or a “shadow line” effect at the butt edge of the shingle. Where such a system is used, the thickness of the flap 28 of the underlayment 20 may be adjusted accordingly to accommodate the prolonged exposure of the flap 28.
Additional advantages of an underlayment 20 of the present invention include advantages associated with the economics and production of the alternative headlap construction shingles used in conjunction with the underlayment 20. These advantages include reduced shingle manufacturing cost and increased production throughput for the alternative headlap construction shingles. Additionally, use of the underlayment 20 of the present invention results in simplified installation as a specific advantage of the roofing system of the present invention as well.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
