CA1313448C - Roofing system having lightweight base sheet - Google Patents
Roofing system having lightweight base sheetInfo
- Publication number
- CA1313448C CA1313448C CA000599046A CA599046A CA1313448C CA 1313448 C CA1313448 C CA 1313448C CA 000599046 A CA000599046 A CA 000599046A CA 599046 A CA599046 A CA 599046A CA 1313448 C CA1313448 C CA 1313448C
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- Canada
- Prior art keywords
- roofing system
- base sheet
- web
- deck
- roof
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
Abstract of the Disclosure Roofing System Having Lightweight Base Sheet A new roofing system comprising a roof deck, a hot bitumen impervious non-woven polyester web base sheet having a polymer latex coating on at least one side thereof, and a roof surface secured to the base sheet to render the roofing system water impermeable.
Description
Description ROOFING SYSTEM H~VING LIGHTWEIGHT BASE SHEET
Technical Field The present invention relates to roofing systems and, more particularly, to weatherproof roofing systems of the type which incorporate a base sheet between the roof deck and the roof surface secured to the base sheet.
Backqround Art It is welL known in roofing construction to utilize a roofing base sheet in the form of a product known as "asphalt paper". Asphalt paper is normally constructed of a non-woven fiberglass web to which a heavy asphalt coating has been applied. Although the asphalt paper is very heavy and difficult to handle, it generally serves to prevent the phenomenon known as "strike-through" which occurs when a layer of hot asphalt is applied over the base sheet and seeps through to the deck below in the construction of a built-up roof and the like.
Strike-through is undesirable since it allows a built-up roof to adhere to the roof deck and thereby can result in substantial difficulty and great expense in later efforts to repair or replace the roof. As is known to those familiar with the roofing art, a roof should normally be able to be easily removed from the roof deck if the ~k strike-through phenomenon is avoided during construction of the original roof.
Although capabl~ of preventing strike-through, it is well known that an asphalt-coated substrate (such as fiberglass but also including other natural or synthetic textile substrates) suffers many other shortcomings when used as a base sheet in roof system con~truction. The shortcomings include the unwieldy nature of asphalt paper as well as high storage and shipping costs which are all due to its relatively great weight. Also, asphalt paper has a tendency to "mat" to the roof deck and thereby create difficulties in removal, and it has an inherent tendency to tear during roof construction or subsequent settling o the roofing system due to its relatively low tear strength.
Thus, there has long been a need for a new product to replace asphalt paper in the construction of roofing systems, particularly built-up roofs, bitumen capsheet roofs, water-shedding sloped roofs and the like. The product would need to be capable of preventing strike-through during roof construction as does asphalt papar, but it should not possess the many shortcomings inherent to heavy asphalt paper.
Disclosure of the Invention In accordance with the present invention, applicant provides an improved roofing system which utilizes a lightweight and high strength polymer latex coated polyester web as a substitute for the traditional asphalt ~L3~3~
paper-type of base sheet. The roofing system of the invention comprises a roof deck, a hot bitumen impervious base sheet thereover comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, and a roof structure secured to the base sheet for rendering the roofing sy~tem water impermeable. The roofing system may be any of those known in the art which have previously utilized asphalt paper in the construction lo thereof and particularly is contemplated to include built-up roofs, water-shedding steep roofs, and bitumen capsheet roofs.
Generally speaking, a built-up roof system as contemplated by the present invention comprises a roof deck, a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, a layer of bitumen applied over the base sheet, a reinforcement sheet applied thereover, and a protective surface layer such as gravel thereon. A
bitumen cap roof system as contemplated by the present invention comprises a roof deck, a hot bitumen impervious base sheet co~prising a non-woven polyester web having a pol~mer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, a layer of bitumen applied over the base sheet, and a protective bituminous membrane which is applied over the bitumen layer. A water-shedding sloped roof system as _4_ ~3~3~
contemplated by the present invention comprises a water-shedding inclined roof deck, a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, and a protectiva surface secured to the base sheet consisting of a material such as clay tile, concrete tile, asphalt shingles, slate shingles, metal shingles, wood shakes or preformed metal panels. It is further contemplated that the roof may be applied to either a wood deck or a metal deck and, if the roofing system includes a metal deck, a layer oP insulation may be provided between the metal deck and the polymer latex coated polyester web base sheet.
The resulting roofing system incorporates a base sheet which is only a fraction of the weight of traditional asphalt paper and yPt possesses inherently greater tear strength. This results in lower storage and shipping costs of the base sheet as well as greater ease of application during construction of a roofing system which incorporates the base sheet.
Accordingly the present invention seeks to provide an improved roofing system which utilizes a lightweight and easy to handle pol~mer latex coated polyester web as a substitute for traditional asphalt paper as a base sheet.
Further the present invent~on fieeks to provide an improved roofing system construction which utilizes a ~3~3~
polymer latex coated non woven polyester web as a base sheet so as to reduce storage and shipping costs of the base sheet material and to provide enhanced base sheet performance qualities during construction o~ a roofing system as well as enhancing long term performance of the roofing system itself.
Some of the aspects o~ the invention having been stated, other aspects will become evident as the description proceeds, when taken in connection with the accompanying drawings.
Brief Description of the Drawinqs Figure 1 is a top plan view, with parts broken away, of a roofing system in accordance with the present invention;
Figure 2 is an exploded cross-sectional view of a representative built-up roof over a plywood deck constructed in accordance with the present invention;
Figure 3 is an exploded cross-sectional view of a representative built-up roof over an in~ulated metal deck constructed in accordance with the present invention;
Figure 4 is an exploded cross-sectional view o~ a representative bitumen capsheet over plywood deck roo~
constructed in accordance with the present invention;
Figure 5 is an exploded cross-sectional view of a representative bitumen capsheet over an insulated metal deck roof constructed in accordance with the present invention; and ~3~34~L8 Figure 6 is an exploded CX065 sectional view of a representative water-shedding steep roof constructed in accordance with the present invention.
Best Mode For Carryinq Out the Invention Referring now to the drawings, Figure 1 illustrates a representative built-up roof construction utili~ing a polymer latex coated non-woven polyester web (such as spun-bonded polyester web) as the base sheet in substitution for conventional "asphalt paper" (asphalt saturated fiberglass web)~ The roofing system, generally designated 10, includes a plywood deck 12 such as is typically found on many flat roof commercial buildings, a polymer latex coated base sheet 14 applied over plywood deck 12, a layer of bitumen or asphalt 16 (including Type I, II, III and IV asphalts, cold tar pitch, cold processed adhesives and mastics and other suitable asphaltic products), a reinforcement ply sheet 18 (such as bitumen saturated polyester, bi-tumen saturated fiberglass, bitumen saturated organic felt, non-bitumen saturated polyester, and non-bitumen saturated fiberglass), a second layer of bitumen 16, and surface layer 19 applied over bitumen layer 16 which may be an aggregate such as gravel or a smooth coating of asphalt or other protective coating such as asphaltic emulsions. Although not shown in the drawings, polymer latex coated base sheet 14 is attached to plywood deck 12 by conventional means known to those familiar with the roofing art such as barbed or ring ~L3~L3~
shanked nails either with or without fastening plates or screws used in conjunction with fastening plates.
Although any suitable polymer latex coated polyester web base sheet 14 may be utilized in roofing system lo as a substitute for asphalt paper, a preferred construction utilizes LUTRADUR brand spun-bonded polyester web manufactured and sold by Freudenberg Spunweb Company of Durham, North Carolina. The polymer latex coating applied to base sheet 14 may be applied to either one or both sides thereof so long as the coating provides a sufficient barrier of polvmer latex thereto to render the web impervious to hot bitumen which would normally be applied thereover during the construction o~ built-up roofs or related roof constructions utilizing base sheet 14 between a deck and a roof surface secured thereover. The polymer latex coating may include but is not limited to one or a combination of the following comonomers: styrene, vinyl acrylic, vinyl chloride, vinyl acetate, vinylidene chloride, and butadiene. The preferred coating is vinyl acrylic which is applied by conventional technique known in the textile related arts such as foamed application.
Also, possible additives to the coating include inorganic fillers, foaming agents, synthetic thickeners, melamine resins, catalysts, water repellents, W inhibitors, and ~5 fire retardants. The primary criteria for the resulting coated polyester web is that it be hot bitumen impervious.
Other roofing systems contemplated by the present invention which utili~e a polymer latex coated non-woven ~3~3~
polyester web base sheet in lieu of asphalt paper may be found with reference to Figures 2 - 6. Figure 2 ~ssentially discloses a representative built-up roof over plywood deck of the same type described in Figure 1. The only distinction being that multiple alternating layers of hot bitumen 16 and ply sheets 18 are applied over polvmer latex coated base sheet 14 prior to the application of surface layer lgo The specific construction details of built-up roofing system 10 as well as other systems described below is a matter of design choice and depends on the specific needs of a particular building.
It should be noted with respect to Figures 2 - 6 that, although not shown in the drawings for greater ease of illustration, nails or screws and fastening plates would be used to secure the polymer latex coated polyester web base sheet to the deck therebeneath. The use of the screws or nails as fastening means is necessary in order to provide protection against naturally occurring wind uplift forces. The advantages of the new polymer latex coated polyester web base sheet 14 over previously known asphalt paper base sheet in preventing wind uplift damage to a roof will be discussed below.
Figure 3 illustrates a typical built-up roof over an insulated metal deck comprising preformed metal deck 22, a layer of insulation 24 (which may consist of a variety of commercially produced products having a wide range of R values such as isocyanurate, urethane, extruded polystyrene, phenolic, fiberglass, and perlite and wood 9 :3!L3~3~
fiber), a polymer latex coated polyester web base sheet 26 (which, not shown, is mechanically attached to metal deck 2~ with metal deck screws and fastener plates by placing the fastener plates on base sheet 26 and then securing the screws through the plates as well as the underlying base sheet 26, insulation layer 24, and metal deck 22), a bitumen layer 27, a layer of reinforcement ply sheet 28, additional bitumen and reinforcement ply sheet layers, and a surface layer 29 (which may also include any of the suitable surfaces described hereinbefore).
With reference now to Figure 4, still another roofing system contemplated by the present invention is illustrated which incorporates a polymer latex coated base sheet as a substitute for conventional asphalt paper. The modified bitumen capsheet over plywood deck roofing system 30 comprises plywood deck 32, a polymer latex polyester web base sheet 34, a layer of bitumen or asphalt 36, and bitumen capsheet 38. Bitumen capsheet 38 is a conventional bituminous roofing membrane known to those familiar with the art such as those modified with APP
(atactic polypropylene) or SBS (styrene butadiene styrene) as well as capsheets incorporating only oxidized bitumen without any modifier. The capsheets may also be reinforced with a polyester, fiberglass or a combination polyester/fiberglass substrate~
Another embodiment of the present invention is shown in Figure 5 which illustrate a typical modified bitumen capsheet over insulated metal deck roofing system ~0 ~3~3~
comprising preformed metal deck 42, an insulation layer 44 (similar to that described in Figure 3 above~, a polymer latex coated polyester web base sheet 46, bitumen layer 48, and bitumen capsheet 49 as described in Figure 4 above. As referenced previously, fastening plates and screws (which are not shown in the drawings) are utilized to secure base sheet 46 and insulation layer 44 to preformed metal deck 42. Finally, with reference to Figure 6, still another embodiment of the roofing system contemplated by the present invention can be appreciated.
Fi~ure 6 discloses a typical water-shedding inclined roofing system 50 comprising plywood deck 52, polymer latex coated polyester web base sheet 5~ (which is attached by roofing nails or fastener plates and screws to plywood deck 52), and asphalt shingles 56. Although asphalt shingles 56 are shown as the top layer of inclined roofing system 50, other roof surfaces could be utilized including clay or concrete tiles, slate or metal shingles, wood shakes, and pxeformed metal panels which are particularly suitable as a mansard cover on commercial buildings.
As can now be fully appreciatedl the present invention contemplates providing a new base sheet material to replace conventionally utilized asphalt paper in a variety of roofing system constructions. Applicant believes that there has long been a need for a new base sheet for built-up roofing systems and other related roof constructions since asphalt paper suffers from so many shortcomings including being very heavy and cumbersome to handlel requiring substantial storage space, requiring high shipping costs, possessing relatively low resistance to shear tearing and thus resulting in roof leaXs due to stresses suffered either during or subsequent to construction of the roof, and possessing a tendency to mat or adhere to the deck therebeneath and thus create difficulties in subsequent roof removal and replacement.
Applicant has surprisingly discovered that a non-woven polyester web provided with a hot bitumen impervious polymer latex coating on at least one side thereof may be substituted ~or asphalt paper with remarkable results. First of all, and perhaps most striking, applicant has found that the polymer latex coated non-woven polyester web base sheet weighs only about ten to fifteen percent (10% - 15%) as much as the asphalt paper which it replaces. This results in very substantial savings in storage space as w~ll as shipping costs. Also, the polymer latex coated non-woven polyester web base sheet is substantially more pliable and thus easier to use during the construction of a roofing system.
Also surprising, it has been found that the polymer latex coated non-woven polyester web base sheet does not tend to mat to an underlying deck as does asphalt paper, and it possesses inherently greater tear strength and resulting resistance to wind uplift forces and shear forces which occur during construction and subsequent utilization of a roofing system. Consequently, applicant has discovered a 3~
new base sheet product for use in roofing systems in lieu of asphalt paper which, although weighing only about ten percent as much as the product it replaces, possesses greater performance characteristics as well as results in substantial cost savings in storage and shipping.
As noted above, the preferred non-woven polyester web for use in the base sheet is sold under the trademark LUTRADUR. The wQight range of this web which may be utilized in a roofing system is from about 25 grams per square meter to 350 grams per square meter with a preferred weight of about 100 grams per square meter. The pol~mer latex coating applied thereto may be any one or combination of monomers such as noted above but preferably could be vinyl acrylic such as HYPOCH ~ R-13 manufactured by High Point Chemicals of High Point, North Carolina, and the coating would typically be applied by conventional methods known to those in the textile industry such as foam application. The polymer latex coating must be applied to at least one side of the LUTRADUR non-woven polyester web and the application must be such that the product is rendered impermeable to hot bitumen applied thereto. Although the amount of polymer latex to be applied to the web is a matter of choice 50 long as the resulting web is impervious to hot bitumen, it is believed that a desirable range is about 30 weight percent to 9O
weight percent for the best results with a preferred weight of about 60 percent. After application of the polymer latex to the LUTRADUR non-woven web utilizing ~3~3~
conventional textile processing methodologyf the resulting product is dried and may be post-treated according to conventional textile techniques. If only one side of the non-woven polyester web i5 coated, it is believed that the coated side should ~e placed adjacent the roof deck in order to obtain the best results. This placement enhances the adhesive attachment of an overlaying roofing layer to the uncoated top side of the base sheet in a roofing system construction.
An example of polymer latex coated non woven polyester web base sheet contrasted to a conventional base sheet is set forth below by way of example although it is understood that many variations are possible according to the type of roofing system being constructed and design choice by the manufacturer of the coated web. The specifics of the representative coated web for use in a novel built-up type roof construction according to the invention are as follows.
Example 1 Polyester/Polymer Latex Fiberglass/Bitumen Base Sheet Base Sheet _ Weh: LUTRADUR (Style MANVILLE
LDH1010 and LDH2010) Fiberglass Sheet Web Weight: 100 grams/meter2 73 grams/meter2 Coating: HIPOCHEM FR-13 Bitumen Vinyl Acrylic Coating Weight: 60 grams/meter2 1,144 grams/meter~
Total Weight: 160 grams/meter2 1,217 grams/meter2 -14 ~3~3~
In sumrnary, the very surprising aspect of the present invention lies in the substitution of an acrylic resin coated polyester web for asphalk paper in roofing system constructions to achieve enhanced performance and reduced storage and shipping costs with a lightweight product weighing only a fraction as much as the roofing product it replaces.
It will be understood that various details of the invention may be c:hanged without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpoRe of limitation--the invention being defined by the claims.
Technical Field The present invention relates to roofing systems and, more particularly, to weatherproof roofing systems of the type which incorporate a base sheet between the roof deck and the roof surface secured to the base sheet.
Backqround Art It is welL known in roofing construction to utilize a roofing base sheet in the form of a product known as "asphalt paper". Asphalt paper is normally constructed of a non-woven fiberglass web to which a heavy asphalt coating has been applied. Although the asphalt paper is very heavy and difficult to handle, it generally serves to prevent the phenomenon known as "strike-through" which occurs when a layer of hot asphalt is applied over the base sheet and seeps through to the deck below in the construction of a built-up roof and the like.
Strike-through is undesirable since it allows a built-up roof to adhere to the roof deck and thereby can result in substantial difficulty and great expense in later efforts to repair or replace the roof. As is known to those familiar with the roofing art, a roof should normally be able to be easily removed from the roof deck if the ~k strike-through phenomenon is avoided during construction of the original roof.
Although capabl~ of preventing strike-through, it is well known that an asphalt-coated substrate (such as fiberglass but also including other natural or synthetic textile substrates) suffers many other shortcomings when used as a base sheet in roof system con~truction. The shortcomings include the unwieldy nature of asphalt paper as well as high storage and shipping costs which are all due to its relatively great weight. Also, asphalt paper has a tendency to "mat" to the roof deck and thereby create difficulties in removal, and it has an inherent tendency to tear during roof construction or subsequent settling o the roofing system due to its relatively low tear strength.
Thus, there has long been a need for a new product to replace asphalt paper in the construction of roofing systems, particularly built-up roofs, bitumen capsheet roofs, water-shedding sloped roofs and the like. The product would need to be capable of preventing strike-through during roof construction as does asphalt papar, but it should not possess the many shortcomings inherent to heavy asphalt paper.
Disclosure of the Invention In accordance with the present invention, applicant provides an improved roofing system which utilizes a lightweight and high strength polymer latex coated polyester web as a substitute for the traditional asphalt ~L3~3~
paper-type of base sheet. The roofing system of the invention comprises a roof deck, a hot bitumen impervious base sheet thereover comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, and a roof structure secured to the base sheet for rendering the roofing sy~tem water impermeable. The roofing system may be any of those known in the art which have previously utilized asphalt paper in the construction lo thereof and particularly is contemplated to include built-up roofs, water-shedding steep roofs, and bitumen capsheet roofs.
Generally speaking, a built-up roof system as contemplated by the present invention comprises a roof deck, a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, a layer of bitumen applied over the base sheet, a reinforcement sheet applied thereover, and a protective surface layer such as gravel thereon. A
bitumen cap roof system as contemplated by the present invention comprises a roof deck, a hot bitumen impervious base sheet co~prising a non-woven polyester web having a pol~mer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, a layer of bitumen applied over the base sheet, and a protective bituminous membrane which is applied over the bitumen layer. A water-shedding sloped roof system as _4_ ~3~3~
contemplated by the present invention comprises a water-shedding inclined roof deck, a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof and which is mechanically fastened to the roof deck, and a protectiva surface secured to the base sheet consisting of a material such as clay tile, concrete tile, asphalt shingles, slate shingles, metal shingles, wood shakes or preformed metal panels. It is further contemplated that the roof may be applied to either a wood deck or a metal deck and, if the roofing system includes a metal deck, a layer oP insulation may be provided between the metal deck and the polymer latex coated polyester web base sheet.
The resulting roofing system incorporates a base sheet which is only a fraction of the weight of traditional asphalt paper and yPt possesses inherently greater tear strength. This results in lower storage and shipping costs of the base sheet as well as greater ease of application during construction of a roofing system which incorporates the base sheet.
Accordingly the present invention seeks to provide an improved roofing system which utilizes a lightweight and easy to handle pol~mer latex coated polyester web as a substitute for traditional asphalt paper as a base sheet.
Further the present invent~on fieeks to provide an improved roofing system construction which utilizes a ~3~3~
polymer latex coated non woven polyester web as a base sheet so as to reduce storage and shipping costs of the base sheet material and to provide enhanced base sheet performance qualities during construction o~ a roofing system as well as enhancing long term performance of the roofing system itself.
Some of the aspects o~ the invention having been stated, other aspects will become evident as the description proceeds, when taken in connection with the accompanying drawings.
Brief Description of the Drawinqs Figure 1 is a top plan view, with parts broken away, of a roofing system in accordance with the present invention;
Figure 2 is an exploded cross-sectional view of a representative built-up roof over a plywood deck constructed in accordance with the present invention;
Figure 3 is an exploded cross-sectional view of a representative built-up roof over an in~ulated metal deck constructed in accordance with the present invention;
Figure 4 is an exploded cross-sectional view o~ a representative bitumen capsheet over plywood deck roo~
constructed in accordance with the present invention;
Figure 5 is an exploded cross-sectional view of a representative bitumen capsheet over an insulated metal deck roof constructed in accordance with the present invention; and ~3~34~L8 Figure 6 is an exploded CX065 sectional view of a representative water-shedding steep roof constructed in accordance with the present invention.
Best Mode For Carryinq Out the Invention Referring now to the drawings, Figure 1 illustrates a representative built-up roof construction utili~ing a polymer latex coated non-woven polyester web (such as spun-bonded polyester web) as the base sheet in substitution for conventional "asphalt paper" (asphalt saturated fiberglass web)~ The roofing system, generally designated 10, includes a plywood deck 12 such as is typically found on many flat roof commercial buildings, a polymer latex coated base sheet 14 applied over plywood deck 12, a layer of bitumen or asphalt 16 (including Type I, II, III and IV asphalts, cold tar pitch, cold processed adhesives and mastics and other suitable asphaltic products), a reinforcement ply sheet 18 (such as bitumen saturated polyester, bi-tumen saturated fiberglass, bitumen saturated organic felt, non-bitumen saturated polyester, and non-bitumen saturated fiberglass), a second layer of bitumen 16, and surface layer 19 applied over bitumen layer 16 which may be an aggregate such as gravel or a smooth coating of asphalt or other protective coating such as asphaltic emulsions. Although not shown in the drawings, polymer latex coated base sheet 14 is attached to plywood deck 12 by conventional means known to those familiar with the roofing art such as barbed or ring ~L3~L3~
shanked nails either with or without fastening plates or screws used in conjunction with fastening plates.
Although any suitable polymer latex coated polyester web base sheet 14 may be utilized in roofing system lo as a substitute for asphalt paper, a preferred construction utilizes LUTRADUR brand spun-bonded polyester web manufactured and sold by Freudenberg Spunweb Company of Durham, North Carolina. The polymer latex coating applied to base sheet 14 may be applied to either one or both sides thereof so long as the coating provides a sufficient barrier of polvmer latex thereto to render the web impervious to hot bitumen which would normally be applied thereover during the construction o~ built-up roofs or related roof constructions utilizing base sheet 14 between a deck and a roof surface secured thereover. The polymer latex coating may include but is not limited to one or a combination of the following comonomers: styrene, vinyl acrylic, vinyl chloride, vinyl acetate, vinylidene chloride, and butadiene. The preferred coating is vinyl acrylic which is applied by conventional technique known in the textile related arts such as foamed application.
Also, possible additives to the coating include inorganic fillers, foaming agents, synthetic thickeners, melamine resins, catalysts, water repellents, W inhibitors, and ~5 fire retardants. The primary criteria for the resulting coated polyester web is that it be hot bitumen impervious.
Other roofing systems contemplated by the present invention which utili~e a polymer latex coated non-woven ~3~3~
polyester web base sheet in lieu of asphalt paper may be found with reference to Figures 2 - 6. Figure 2 ~ssentially discloses a representative built-up roof over plywood deck of the same type described in Figure 1. The only distinction being that multiple alternating layers of hot bitumen 16 and ply sheets 18 are applied over polvmer latex coated base sheet 14 prior to the application of surface layer lgo The specific construction details of built-up roofing system 10 as well as other systems described below is a matter of design choice and depends on the specific needs of a particular building.
It should be noted with respect to Figures 2 - 6 that, although not shown in the drawings for greater ease of illustration, nails or screws and fastening plates would be used to secure the polymer latex coated polyester web base sheet to the deck therebeneath. The use of the screws or nails as fastening means is necessary in order to provide protection against naturally occurring wind uplift forces. The advantages of the new polymer latex coated polyester web base sheet 14 over previously known asphalt paper base sheet in preventing wind uplift damage to a roof will be discussed below.
Figure 3 illustrates a typical built-up roof over an insulated metal deck comprising preformed metal deck 22, a layer of insulation 24 (which may consist of a variety of commercially produced products having a wide range of R values such as isocyanurate, urethane, extruded polystyrene, phenolic, fiberglass, and perlite and wood 9 :3!L3~3~
fiber), a polymer latex coated polyester web base sheet 26 (which, not shown, is mechanically attached to metal deck 2~ with metal deck screws and fastener plates by placing the fastener plates on base sheet 26 and then securing the screws through the plates as well as the underlying base sheet 26, insulation layer 24, and metal deck 22), a bitumen layer 27, a layer of reinforcement ply sheet 28, additional bitumen and reinforcement ply sheet layers, and a surface layer 29 (which may also include any of the suitable surfaces described hereinbefore).
With reference now to Figure 4, still another roofing system contemplated by the present invention is illustrated which incorporates a polymer latex coated base sheet as a substitute for conventional asphalt paper. The modified bitumen capsheet over plywood deck roofing system 30 comprises plywood deck 32, a polymer latex polyester web base sheet 34, a layer of bitumen or asphalt 36, and bitumen capsheet 38. Bitumen capsheet 38 is a conventional bituminous roofing membrane known to those familiar with the art such as those modified with APP
(atactic polypropylene) or SBS (styrene butadiene styrene) as well as capsheets incorporating only oxidized bitumen without any modifier. The capsheets may also be reinforced with a polyester, fiberglass or a combination polyester/fiberglass substrate~
Another embodiment of the present invention is shown in Figure 5 which illustrate a typical modified bitumen capsheet over insulated metal deck roofing system ~0 ~3~3~
comprising preformed metal deck 42, an insulation layer 44 (similar to that described in Figure 3 above~, a polymer latex coated polyester web base sheet 46, bitumen layer 48, and bitumen capsheet 49 as described in Figure 4 above. As referenced previously, fastening plates and screws (which are not shown in the drawings) are utilized to secure base sheet 46 and insulation layer 44 to preformed metal deck 42. Finally, with reference to Figure 6, still another embodiment of the roofing system contemplated by the present invention can be appreciated.
Fi~ure 6 discloses a typical water-shedding inclined roofing system 50 comprising plywood deck 52, polymer latex coated polyester web base sheet 5~ (which is attached by roofing nails or fastener plates and screws to plywood deck 52), and asphalt shingles 56. Although asphalt shingles 56 are shown as the top layer of inclined roofing system 50, other roof surfaces could be utilized including clay or concrete tiles, slate or metal shingles, wood shakes, and pxeformed metal panels which are particularly suitable as a mansard cover on commercial buildings.
As can now be fully appreciatedl the present invention contemplates providing a new base sheet material to replace conventionally utilized asphalt paper in a variety of roofing system constructions. Applicant believes that there has long been a need for a new base sheet for built-up roofing systems and other related roof constructions since asphalt paper suffers from so many shortcomings including being very heavy and cumbersome to handlel requiring substantial storage space, requiring high shipping costs, possessing relatively low resistance to shear tearing and thus resulting in roof leaXs due to stresses suffered either during or subsequent to construction of the roof, and possessing a tendency to mat or adhere to the deck therebeneath and thus create difficulties in subsequent roof removal and replacement.
Applicant has surprisingly discovered that a non-woven polyester web provided with a hot bitumen impervious polymer latex coating on at least one side thereof may be substituted ~or asphalt paper with remarkable results. First of all, and perhaps most striking, applicant has found that the polymer latex coated non-woven polyester web base sheet weighs only about ten to fifteen percent (10% - 15%) as much as the asphalt paper which it replaces. This results in very substantial savings in storage space as w~ll as shipping costs. Also, the polymer latex coated non-woven polyester web base sheet is substantially more pliable and thus easier to use during the construction of a roofing system.
Also surprising, it has been found that the polymer latex coated non-woven polyester web base sheet does not tend to mat to an underlying deck as does asphalt paper, and it possesses inherently greater tear strength and resulting resistance to wind uplift forces and shear forces which occur during construction and subsequent utilization of a roofing system. Consequently, applicant has discovered a 3~
new base sheet product for use in roofing systems in lieu of asphalt paper which, although weighing only about ten percent as much as the product it replaces, possesses greater performance characteristics as well as results in substantial cost savings in storage and shipping.
As noted above, the preferred non-woven polyester web for use in the base sheet is sold under the trademark LUTRADUR. The wQight range of this web which may be utilized in a roofing system is from about 25 grams per square meter to 350 grams per square meter with a preferred weight of about 100 grams per square meter. The pol~mer latex coating applied thereto may be any one or combination of monomers such as noted above but preferably could be vinyl acrylic such as HYPOCH ~ R-13 manufactured by High Point Chemicals of High Point, North Carolina, and the coating would typically be applied by conventional methods known to those in the textile industry such as foam application. The polymer latex coating must be applied to at least one side of the LUTRADUR non-woven polyester web and the application must be such that the product is rendered impermeable to hot bitumen applied thereto. Although the amount of polymer latex to be applied to the web is a matter of choice 50 long as the resulting web is impervious to hot bitumen, it is believed that a desirable range is about 30 weight percent to 9O
weight percent for the best results with a preferred weight of about 60 percent. After application of the polymer latex to the LUTRADUR non-woven web utilizing ~3~3~
conventional textile processing methodologyf the resulting product is dried and may be post-treated according to conventional textile techniques. If only one side of the non-woven polyester web i5 coated, it is believed that the coated side should ~e placed adjacent the roof deck in order to obtain the best results. This placement enhances the adhesive attachment of an overlaying roofing layer to the uncoated top side of the base sheet in a roofing system construction.
An example of polymer latex coated non woven polyester web base sheet contrasted to a conventional base sheet is set forth below by way of example although it is understood that many variations are possible according to the type of roofing system being constructed and design choice by the manufacturer of the coated web. The specifics of the representative coated web for use in a novel built-up type roof construction according to the invention are as follows.
Example 1 Polyester/Polymer Latex Fiberglass/Bitumen Base Sheet Base Sheet _ Weh: LUTRADUR (Style MANVILLE
LDH1010 and LDH2010) Fiberglass Sheet Web Weight: 100 grams/meter2 73 grams/meter2 Coating: HIPOCHEM FR-13 Bitumen Vinyl Acrylic Coating Weight: 60 grams/meter2 1,144 grams/meter~
Total Weight: 160 grams/meter2 1,217 grams/meter2 -14 ~3~3~
In sumrnary, the very surprising aspect of the present invention lies in the substitution of an acrylic resin coated polyester web for asphalk paper in roofing system constructions to achieve enhanced performance and reduced storage and shipping costs with a lightweight product weighing only a fraction as much as the roofing product it replaces.
It will be understood that various details of the invention may be c:hanged without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpoRe of limitation--the invention being defined by the claims.
Claims (35)
1. A roofing system comprising:
a roof deck;
a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck; and a roof surface secured to said base sheet for rendering said roofing system water impermeable.
a roof deck;
a hot bitumen impervious base sheet comprising a non-woven polyester web having a polymer latex coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck; and a roof surface secured to said base sheet for rendering said roofing system water impermeable.
2. A roofing system according to claim 1 wherein said roof deck is a plywood deck.
3. A roofing system according to claim 1 wherein said flat roof deck is a metal deck.
4. A roofing system according to claim 3 wherein said roofing system includes a layer of insulation between said metal deck and said base sheet.
5. A roofing system according to claim 1 wherein said non-woven polyester web is a spun-bonded web having a weight between about 25 and 350 grams per square meter.
6. A roofing system according to claim 1 wherein said polymer latex is vinyl acrylic.
7. A roofing system according to claim 6 wherein said web is coated on only one side with vinyl acrylic.
8. A roofing system according to claim 7 wherein said vinyl acrylic coated side of said web is adjacent said roof deck.
9. A roofing system according to claim 6 wherein said web is coated on both sides with vinyl acrylic.
10. A roofing system according to claim 1 wherein said roof surface comprises at least one layer of bitumen, at least one reinforcement sheet layer, and a protective surface layer.
11. A roofing system according to claim 1 wherein said roof surface comprises at least one layer of bitumen and a protective bituminous roofing membrane.
12. A roofing system according to claim 1 wherein said roof surface comprises a material selected from the group consisting of clay tile, concrete tile, asphalt shingles, slate shingles, metal shingles, wood shakes and performed metal panels.
13. A roofing system comprising:
a roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck;
a layer of bitumen applied over said base sheet;
a reinforcement sheet applied over said layer of bitumen; and a protective surface layer applied over said reinforcement sheet.
a roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck;
a layer of bitumen applied over said base sheet;
a reinforcement sheet applied over said layer of bitumen; and a protective surface layer applied over said reinforcement sheet.
14. A roofing system according to claim 13 wherein said roof deck is a plywood deck.
15. A roofing system according to claim 13 wherein said roof deck is a metal deck.
16. A roofing system according to claim 15 including a layer of insulation between said metal deck and said base sheet.
17. A roofing system according to claim 13 wherein said web has a weight between about 25 - 350 grams per square meter.
18. A roofing system according to claim 13 wherein said vinyl acrylic coated side of said web is adjacent said roof deck.
19. A roofing system according to claim 13 wherein said web is coated on both sides with vinyl acrylic.
20. A roofing system comprising:
a roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck;
a layer of bitumen applied over said base sheet; and a protective bituminous membrane applied over said bitumen layer.
a roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck;
a layer of bitumen applied over said base sheet; and a protective bituminous membrane applied over said bitumen layer.
21. A roofing system according to claim 20 wherein said roof deck is plywood.
22. A roofing system according to claim 20 wherein said roof deck is a metal deck.
23. A roofing system according to claim 22 including a layer of insulation between said metal deck and said base sheet.
24. A roofing system according to claim 20 wherein said web has a weight of about 25 - 350 grams per square meter.
25. A roofing system according to claim 20 wherein said vinyl acrylic coated side of said web is adjacent said roof deck.
26. A roofing system according to claim 20 wherein said web is coated on both sides with vinyl acrylic.
27. A roofing system comprising:
a water shedding inclined plywood roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck; and a protective surface secured to said base sheet comprising a material selected from the group consisting of clay tile, concrete tile, asphalt shingles, slate shingles, metal shingles, wood shakes and preformed metal panels.
a water shedding inclined plywood roof deck;
a hot bitumen impervious base sheet comprising a spun-bonded non-woven polyester web having a vinyl acrylic coating on at least one side thereof, said base sheet being mechanically fastened to said roof deck; and a protective surface secured to said base sheet comprising a material selected from the group consisting of clay tile, concrete tile, asphalt shingles, slate shingles, metal shingles, wood shakes and preformed metal panels.
28. A roofing system according to claim 27 wherein said web has a weight of about 25 - 350 grams per square meter.
29. A roofing system according to claim 27 wherein said vinyl acrylic coated side of said web is adjacent said roof deck.
30. A roofing system according to claim 27 wherein said web is coated on both sides with vinyl acrylic.
31. In a roofing system of the type having a hot bitumen impervious base sheet mechanically fastened to a roof deck therebeneath and a roof surface secured to said base sheet for rendering said roofing system water impermeable, the improvement wherein said base sheet comprises a non-woven polyester web having a polymer latex coating on at least one side thereof.
32. A roofing system according to claim 31 wherein said non-woven polyester web is a spun-bonded polyester web having a weight between about 25 and 350 grams per square meter.
33. A roofing system according to claim 31 wherein said polymer latex is vinyl acrylic.
34. A roofing system according to claim 33 wherein said web is coated on only one side with vinyl acrylic.
35. A roofing system according to claim 33 wherein said web is coated on both sides with vinyl acrylic.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US29406089A | 1989-01-05 | 1989-01-05 | |
| US294,060 | 1989-01-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1313448C true CA1313448C (en) | 1993-02-09 |
Family
ID=23131712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000599046A Expired - Fee Related CA1313448C (en) | 1989-01-05 | 1989-05-08 | Roofing system having lightweight base sheet |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1313448C (en) |
-
1989
- 1989-05-08 CA CA000599046A patent/CA1313448C/en not_active Expired - Fee Related
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