Spaced sheathing roofing system and method of installing same

The present invention is a spaced sheathing roofing system and method in which roof cladding is placed onto batten strips positioned on roof rafters. The roof cladding is attached using an adhesive. The attachment component is preferably a polymer adhesive, more preferably a polyurethane, for adhering the roof cladding. The adhesive is preferably sprayed onto the lower surface of the placed roof cladding while also being sprayed onto the batten strips and the supporting truss rafters. The sprayed adhesive bonds the adjacent roof cladding together and also bonds the roof cladding to the batten strips to form a monolithic structure. In addition, the sprayed layer of adhesive forms an insulative layer while also forming a waterproof barrier.

STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a spaced sheathing roofing system and method of installing same, and particularly to a spaced sheathing roofing system providing enhanced insulation and waterproofing properties.

2. Description of the Related Art

There are two basic techniques of pitched roof construction. The most common technique involves nailing sheets of wood, typically plywood or decking material, to truss rafters to form a pitched roof deck. The pitched roof deck is overlaid with a roof substrate made of a waterproofing material. Typically, the waterproofing material forming the roof substrate is a roll goods membrane or underlayment comprising one or more plies of asphaltic or modified bitumen impregnated felt attached to the pitched roof deck by nails and/or adhesive. Felt is generally made of wood pulp and rag or of asbestos, polyester or glass fibers. Roof cladding provides the outer roof covering on the pitched roof system. One example of roof cladding is a roof tile. Roof tiles are extremely durable and provide significant aesthetic and decorative effects to the structures to which they are applied. Roof claddings may be made of cementitious materials and also brick, stone, clay, plastic, wood, metal, rubber or bituminous materials.

Roof cladding is secured primarily to the pitched roof system with mechanical fasteners. Nails are the primary mechanical fasteners for securing roof cladding to a wood deck. Roof tiles are commonly secured with a nail inserted through a hole in the roof tile and driven through the roof substrate and wood deck. Mortar is sometimes used in conjunction with nails to provide holding force of the roof tile to the roof deck.

The use of a plural component adhesive for attaching roof cladding to the exterior surface of a pitched roof deck is disclosed in assignee's U.S. Pat. No. 5,362,342. The '342 patent discloses a method of bonding tile roof components to the roof substrate utilizing polyurethane foam as the bonding medium. The method includes the step of applying under low pressure a stream of two component foamable liquid polyurethane on a prepared roof substrate. The foamable liquid polyurethane has a density preferably in the range of one and one-half to two pounds per cubic foot and a reactivity period in the range of one and one-half to four minutes. The foamable liquid polyurethane is preferably applied at a rate in the range of two to three pounds per minute. The tile roof component is placed into contact with the foamable liquid polyurethane during the reactivity period of the foamable liquid polyurethane.

The second technique of pitched roof construction is referred to as a spaced sheathing roof assembly. This technique has more limited applications and is used in certain geographic locations. In the spaced sheathing technique, batten strips, generally two to six inches wide, are affixed perpendicularly to the truss rafters and spaced according to the dimension of the selected roof cladding. The roof cladding, typically concrete or clay roof tiles, are allowed to be loose lain on the batten strips. Alternatively, the roof tiles may be occasionally nailed to the batten strips. When desired, an optional underlayment is positioned above the truss rafters and below the batten strips. Ferrous roof panels may be installed, using a limited number of mechanical fasteners on similarly arranged batten strips. Nonferrous cladding such as wood shingles may be installed and nailed to the batten strips in the same manner.

In the conventional spaced sheathing roof assembly, each of these roof coverings offers its own economic and aesthetic advantage, but all have similar shortcomings. The shortcomings of the spaced sheathing roof assembly are that it provides little or no insulation value to the structure, little protection from leaking during high wind and unexpected high rainfall events as well as, structural movement or racking of the roof assembly during high wind events and seismic disturbances.

It is desirable to have a spaced sheathing roof system that provides insulative value to the structure, significant leak protection and resistance to structural movement or racking of the roof assembly. It is also desirable to have an adhesive attachment assembly and method for concrete, slay and slate roof tiles and ferrous and non-ferrous roof panels for spaced sheathing applications.

Furthermore, it is desirable that the method of installation be simple, non-labor intensive, economical and not require excessive installation time. Furthermore, the roofing system should withstand the long-term effects of temperature and climatic variations experienced by the roofing system under normal circumstances

BRIEF SUMMARY OF THE INVENTION

The present invention is an improved spaced sheathing roof system that provides insulative value to the structure, significant leak protection and resistance to structural movement or racking of the roof assembly. The present invention includes an adhesive attachment assembly and method for concrete, slay and slate roof tiles and ferrous and nonferrous roof panels for spaced sheathing applications. Furthermore, the method of installation of the present invention is simple, non-labor intensive, economical and does not require excessive installation time. Furthermore, the roofing system of the present invention will withstand the long-term effects of temperature and climatic variations experienced by the roofing system under normal circumstances.

One embodiment of the present invention is a spaced sheathing roofing system and method in which roof cladding is placed onto batten strips positioned on roof rafters. The roof cladding is attached using an adhesive in the spaced sheathing application of the present invention. The attachment component of the present invention is preferably a polymer adhesive, more preferably a polyurethane, for adhering the roof cladding. The adhesive is preferably sprayed onto the lower surface of the placed roof cladding while also being sprayed onto the batten strips and the supporting truss rafters. The sprayed adhesive bonds the adjacent roof cladding together and also bonds the roof cladding to the batten strips to form a monolithic structure. In addition, the sprayed layer of adhesive forms an insulative layer while also forming a waterproof barrier.

Due to the unexpected climatic and seismic changes in various geographic locations, a method to provide secure attachment of the desired cladding has been developed. The application of insulating adhesive to the underside of each of the aforementioned claddings provides the necessary solution to address the shortcomings of the spaced sheathing roofing system. The application of the insulating adhesive locks together each member of the roofing system, cladding, batten strips and rafters, providing a substantially stronger roof assembly. The insulating adhesive is preferably a polyurethane chemical system, and more preferably a plural component polyurethane chemical system. A preferred insulating adhesive is a froth polyurethane adhesive and more preferably a froth foam polyurethane adhesive. Further, the polyurethane insulating adhesive has a dramatic effect on lessening the heat energy transfer into the attic space, thus lowering energy cost; provides “walk-ability” of the selected cladding by providing reinforcement to the underside of the cladding; eliminates the need for a waterproofing membrane since the insulating adhesive completely seals the underside of the selected cladding material; and during high wind events or seismic activity the polyurethane adhesive prevents loss of the roof cladding due to the resultant monolithic nature of the roof structure as a benefit of the adhesive application.

The method of the present invention can be used to adhesively attach concrete, slay, and slate roof tiles and ferrous and non-ferrous roof panels for spaced sheathing applications. The method of attachment for roof cladding in spaced sheathing applications preferably uses a plural component polyurethane adhesive.

DETAILED DESCRIPTION OF THE INVENTION

The spaced sheathing roofing system and method of installing same, generally designated as100, will now be described in greater detail with specific reference to the drawings. The spaced sheathing roof system100includes a roof component, designated generally as10, known as a roof cladding or roof tile. An example of one such roof component is shown in perspective view inFIGS. 1 and 2.FIG. 1shows the upper side andFIG. 2shows the lower side of the roof component10. The roof component10shown inFIGS. 1 and 2is commercially available from Monier-Raymond Company. It is to be understood that the present invention100is not limited to the roof tile design shown in the drawings, but is equally applicable to a variety of other shapes and types of roof components well known to those skilled in the art. For example, flat roof tiles and reverse curve roof tiles can be used with the system and method100. Typically, the tile components10are made from cementitious or clay materials. It is also to be understood that the system and method of the present invention100is not limited to clay or cementitious roof tiles10but is also applicable to roof components10made from other materials including, but not limited to, brick, stone, ferrous, plastic, wood, rubber, or bituminous materials.

As shown inFIGS. 1 and 2, the roof component10typically includes an interlocking connection at the first and second longitudinal edges12and14, respectively, of the roof component10, to additionally form a water lock. Referring toFIG. 3, the second edge14of the first roof component10mates with the first edge12of an adjoining second roof component10. This type of interlocking connection for tile roof components10is well known in the art. The tile roof component10as shown inFIGS. 1 and 2includes a head portion13and a nose portion15. Preferably, the head portion13includes one or more head lugs13aon the lower side of the roof component10for reasons which will be explained below. The lower side of the nose portion15may include one or more nose lugs15aon the lower side of the roof component10.

Referring toFIGS. 3 and 4, a plurality of roof truss rafters16for supporting the spaced sheathing roofing system100are installed in the house or building structure in the customary manner. The rafters16may have any angle of inclination as is customary in the building industry. Typically, the truss rafters16are on 24-inch or 16-inch centers. A plurality of batten strips18are secured, preferably by nails, to the upper surface16aof the rafters16. Batten strips18can be wooden, metal, or other construction materials such as are known to persons of skill in the art. Typically, the batten strips18are affixed perpendicularly to the truss rafters16. Preferably, the batten strips18have a uniform width of between two to six inches and about a one inch thickness. The spacing of the batten strips18is dependent on the dimensions of the selected roof cladding10. It is to be understood that the size and spacing of the batten strips will be determined based upon various factors, including but not limited to, design loads, rafter spacing, and tile type.

Still referring toFIGS. 3 and 4, the roof cladding10is placed in rows beginning along the lower edge of the roof. As shown inFIG. 4, preferably the roof cladding10is placed onto the lower batten strip18so that the head lug13aof the roof cladding10is contacting the batten strip18. The lower row of roof cladding10is similarly placed and preferably interlocked with the adjacent roof cladding10. A second row of roof cladding10is similarly placed with the head lug13acontacting the respective batten strip18. The second row of roof cladding10overlaps the lower row of roof cladding10as shown inFIGS. 3 and 4. Preferably, the nose lugs15ainterengage with the upper side of the lower course of roof cladding10to form a weather barrier to help prevent free passage of wind, rain, etc. The additional courses of tiles are similarly placed onto the roof. If desired, the roof cladding10may be secured with fasteners, for example nails, to the batten strips18. It may be desirable to fasten only a few of the tiles10to the batten strips18.

Upon placing one or more courses of roof cladding10on the batten strips18of the roof, the roof cladding10is attached using an adhesive30. The roof cladding attachment component30is preferably a polymer adhesive, and more preferably a polyurethane. Referring toFIG. 5, the adhesive30is preferably sprayed onto the lower surface of the placed roof cladding10while also being sprayed onto the batten strips18. Although not required, the adhesive30may also be sprayed onto the supporting truss rafters16. The sprayed adhesive30bonds the adjacent roof cladding10together and also bonds the roof cladding10to the batten strips18to form a monolithic structure. In addition, the sprayed layer of adhesive30forms an insulative layer while also forming a waterproof barrier. The adhesive layer can have any desired thickness, and preferably has a final thickness in the range of approximately two to four inches.

Preferably, the polymer adhesive30is a polyurethane described in greater detail below. One suitable polymer adhesive30and system for applying is disclosed in assignee's U.S. Pat. No. 5,362,342, issued to Murray et al., which is incorporated by reference. However, it is to be understood that the present invention is not limited to the system and adhesive disclosed in U.S. Pat. No. 5,362,342.

The polymer adhesive30may be a foamable or a non-foamable polymer adhesive. Preferably, the polymer adhesive30is a plural component, liquid polyurethane foam. The significant advantage of the plural component polyurethane foam is being able to walk on the installed roof components10shortly after the roof components10have been installed without affecting the bond between the roof components10as well as with the batten strips18. The reactivity period or rise time of the plural component liquid polyurethane foam30of the present invention is preferably about one-half to about ten minutes and more preferably about one and one-half to about four minutes. During the reactivity period, the preferred liquid polyurethane foam30is an expanding foam, which fills gaps and imperfections. The resulting foam30provides excellent bonding between the roof components10and also with the batten strips18due to the adhesive properties of the urethane.

Plural component polyurethane insulating adhesives that may be used for this application may be carbon dioxide blown, hydrocarbon blown, fluorocarbon blown (141b, 245fa or equivalent) or gaseous fluorocarbon blown (R22, 134a, 142b or equivalent) or any combination of these materials. It is particularly advantageous to use an insulating foam adhesive blown with gaseous blowing agents due to the simplicity of the application. The simplicity of application includes low pressure, low velocity spray equipment requiring no preheated chemical components or equipment. One such system of equipment suitable for use with the present invention is disclosed in assignee's U.S. Pat. No. 5,362,342. A low velocity spray application reduces airborne particulates and unwanted overspray reducing job clean-up expenses. Low velocity spray equipment is substantially lower in cost, does not require an electrical supply source and is more easily maintained. It is to be understood that various other types of equipment may be used to apply the adhesives in practicing the present invention. Preferably, the plural component polyurethane insulating adhesive includes “A” and “B” components. The isocyanate or “A” component of the chemical system is polymeric methylene diisocyanate (PMDI) and may contain surfactant and a blowing agent. The resin or “B” component of the chemical system is a blend of polyglycols which includes sucrose glycerine, mannic, polyethylene, polypropylene and polyester polyols combined with appropriate amounts of amine and metal catalysts and cell control surfactants. The resin blend will also contain the selected blowing agent.

The foamable liquid polyurethane30is preferably a froth foam. Froth foam chemistry is well known in the art of urethane foams. The froth foam may be formed by using blowing agents such as hydrogenated chlorofluorocarbon R22 (HCFC-R22), hydrogenated fluorocarbon 134a (HFC-134a), or chlorofluorocarbon R12 (CFC-R12). Preferably, the froth foam30is formed by using the hydrogenated blowing agents HCFC-R22 or HFC-134a, and not CFC-R12 due to CFC-R12's reported deleterious effects to the earth's ozone layer.

In the preferred method, the froth foam30has a consistency similar to a foamy shaving cream. The froth foam is preferable over other types of foams because it can be neatly and accurately dispensed without blowing or overspraying onto other areas of the roof. The preferred liquid polyurethane30with its shaving cream consistency does not run when placed onto a steeply pitched roof, but remains where it is sprayed. This ensures that the adhesive bond will be formed at the appropriate locations of the roof component10. Additionally, the froth foam30begins expanding immediately upon application to the roofing component10and batten strip18and results in a firm bond between adjacent roofing components10and the batten strips18.

The liquid polyurethane30preferably has a density of about one to about eight pounds per cubic foot. It may be desirable to minimize the density of the liquid polyurethane30to minimize the weight on the roof while still providing an excellent bond. It has been found to be more preferable to have a foam density of about one and one-half to about two pounds per cubic foot. The application rate of the liquid polyurethane30is preferably about one to about six pounds per minute and more preferably about two to about three pounds per minute.

Preferably, the foamable liquid polyurethane30expands and fills the gaps between the batten strip18and the roof component10and gaps between the roof components10. The excess foam continues expanding and provides further bonding with adjacent surface areas of the roof components10.

Referring toFIG. 5, the expanding foam30also provides a bond between the upper roof component10and the lower roof component10at the overlapping portion where the expanding foam can fill any gap between the two roof components10. This further enhances the overall bonding capacity of the roof components10to the roof.

Although the use of polyurethane spray foam on flat roof decks is an accepted practice, such applications are on the exterior surface of a closed deck system. The deck is generally wood, concrete or steel and the spray foam must be protected from U.V. degradation using multiple inches of stone or a coating of acrylic or silicone. The application of the plural component polyurethane insulating adhesive of the present invention is applied to the underside of the roof cladding and is not exposed to U.V. degradation, thus requiring no after coating.

It is to be understood that the present invention insulates the roof to provide a more energy efficient house or building and maintains better control over attic temperatures. The present invention may be employed as an after market application or in a new construction and is equally beneficial in commercial construction as well as residential. The present invention may be a substitute for a conventional pitched roof system thus eliminating the need for plywood decking and felt.

One embodiment of a pitched roofing system and method of installing same according to the present invention has thus been set forth. However, the invention should not be unduly limited to the foregoing, which has been set forth for illustrative purposes only. Various modifications and alterations of the invention will be apparent to those skilled in the art, without departing from the true scope of the invention.