Roofing system and apparatus for applying rolled roofing material

Abstract

An adhesive for securing a roofing system to a substrate includes a magnesium oxide matrix having dispersed therethrough a plurality of particles or fibers. The dispersant coating is operative to suppress electrostatic attraction between the particles or fibers. An elastomeric overlayer is placed in interfacial contact with the magnesium oxide matrix containing the plurality of particles or fibers prior to set of the matrix so as to form a bond therebetween. A roofing system is detailed that includes an intermediate layer having an asphaltic layer that terminates in an asphaltic surface and an exposed non-asphaltic fibrous surface. An elastomeric outer weatherproof coating is applied in adhesive contact with the fibrous surface resulting in a weatherproof roofing system. The elastomeric outer weatherproof coating is amenable to application with a sprayer or roller with the non-asphaltic fibrous surface absorptive of such a liquid coating.

Description

FIELD OF THE INVENTION

The present invention in general relates to low profile roofing systems, and in particular to an exposed fiber layer roofing membrane with conventional asphaltic roofing membranes or a novel magnesium oxide adhesive slurry.

BACKGROUND OF THE INVENTION

Safety concerns and regulations are making the inclusion of fire-resistant boards within a roofing system more commonplace. Currently, structural insulated panels or other prefabricated sheets are used for this purpose. These panels are typically produced from cellulose reinforced cement board as outside skins and applied as a sheathing to a wall or roof section. The fire-resistant properties of such a board are enhanced by application of a layer of calcium sulfate, magnesium oxy-chloride, or asbestos onto the board or forming such a board from magnesium oxy-chloride, while attachment of panels for wall sections is an efficient process owing to the large number of passageways associated with a wall surface. However, in a roofing setting such fire-resistant boards create considerable difficulties associated with transporting heavy and brittle cementitious panels to the point of application. The subsequent operation to cut such panels within industry acceptable tolerances represents a time-consuming and skilled task. Considerable efficiencies in applying fire-resistant low slope roofs could be achieved through the elimination of fire-resistant boards in roofing systems.

Recognition of the societal value of reflectance and emittance standards for roof weatherproofing membrane barriers has created a desire to produce a roofing system with varied properties which is amenable to use in a re-roofing application. While various intermediate layers between a roof substrate and an external membrane have been tried to achieve these standards, these have met with limited success.

Thus, there exists a need for a new roofing intermediate layer that is capable of securing a membrane layer to an overlying membrane. With the use of magnesium oxide based fire-resistant intermediate layer formable in place on a roof surface, the resulting magnesium oxide layer acts as an adhesive towards a variety of component surfaces found in a commercial roofing system including an overlying membrane. Alternatively, an exposed fibrous surface of an intermediate layer asphaltically joined to an underlayer receives an elastomeric overcoat to form a weatherproof roofing system.

SUMMARY OF THE INVENTION

An adhesive for securing a roofing system to a substrate includes a magnesium oxide matrix having dispersed therethrough a plurality of particles or fibers, the particles or fibers having a dispersant coating applied thereto prior to mixing with the magnesium oxide matrix. The dispersant coating is operative to suppress electrostatic attraction between the particles or fibers. An elastomeric overlayer is placed in interfacial contact with the magnesium oxide matrix containing the plurality of particles or fibers prior to set of the matrix so as to form a bond therebetween.

A roofing system is detailed that includes an intermediate layer having an asphaltic layer that terminates in an asphaltic surface and an exposed non-asphaltic fibrous surface. A roof substrate is placed in adhesive contact with the asphaltic surface of the intermediate layer. An elastomeric outer weatherproof coating is applied in adhesive contact with the fibrous surface resulting in a weatherproof roofing system. The elastomeric outer weatherproof coating is amenable to application with a sprayer or roller with the non-asphaltic fibrous surface absorptive of such a liquid coating.

A process for applying a roofing system to a roof substrate includes mixing in proximity to a roof substrate a quantity of dispersant coated particles or fibers with a magnesium oxide slurry to form a wet magnesium oxide matrix. The wet magnesium oxide matrix is then extruded onto the roof substrate. An elastomeric membrane surface is then contacted with the wet magnesium oxide matrix to complete the roofing system. Exemplary elastomeric membrane surfaces include polyester fiber, styrene-butadiene-styrene (SBS) modified granular surface, and fleece backing on polyvinyl chloride.

A roofing system is provided that includes an intermediate layer having an asphaltic surface and an exposed non-asphaltic fibrous surface. The asphaltic surface is in adhesive contact with a roof substrate. An elastomeric outer weatherproof coating is provided in adhesive contact with the fibrous surface to complete the roofing system installation. A white or silvered elastomeric outer weatherproof coating greatly enhances the reflectance and emittance of the resulting roofing system.

An asphalt applicator is provided that includes a molten asphalt reservoir having a base and an opening for receiving the solid asphalt charges or pieces. A heating element is provided within the reservoir to melt the solid asphalt charges or pieces. A tip angled to insert within a lap formed between rolled roofing material is placed in fluid communication with the reservoir base. A valve intermediate between the reservoir and the tip provides for metering of molten asphalt into the lap. A wheel external to and supporting the reservoir supports the applicator weight and also presses freshly applied asphalt between the lap.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cutaway perspective view of a roof system containing an inventive magnesium oxide adhesive;

FIG. 2 is a partial cutaway perspective exploded view of an exposed fiber surface intermediate layer overlayered with an elastomeric coating; and

FIG. 3 is a perspective view of an applicator apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention has utility in the formation of an intermediate layer binding a roofing substrate to an overlying weatherproofing membrane. In a preferred embodiment, fire-resistant adhesive is provided for securing a roof system to a cementitious substrate. Alternatively, an intermediate roll material is applied with an asphaltic bottom layer contacting a roof substrate and having an exposed fibrous layer well suited to bond to a bottom surface of an overlying outer membrane. The present invention finds uses in roofing materials, structural coatings, and construction panel fabrication. Through the admixing of particulate or fiber having a dispersing coating thereon to suppress electrostatic attraction and make the particulate or fiber hydrophilic, a magnesium oxide cement matrix is rendered sufficiently viscous to preclude flow out through voids or openings within a substrate deck level. Such particulate or fiber also has the added benefit of reducing the overall density of the resulting adhesive.

As used herein, a magnesium oxide cement is defined to include magnesium oxy-chloride, magnesium oxy-sulfate and magnesium phosphate where the terms “cement” and “matrix” are used herein synonymously independent of whether particulate or fibers are dispersed therein.

A magnesium oxide cement according to the present invention is loaded with synthetic polymer particulate or fibers. A synthetic polymer particulate or fiber operative herein is a hydrophobic expanded material illustratively including polystyrene, polyisocyanurate, polypropylene, polyethylene, other polyalkylenes and polyurethanes. Preferably, the synthetic polymer is polystyrene. As a result of synthetic polymer particulate grinding and sieving, electrostatic attractions develop therebetween.

A dispersant coating operative herein to suppress electrostatic attraction between synthetic polymer particulate particles includes a wide variety of materials. It is appreciated that such a coating also optionally affords benefits associated with increasing insolubility, plasticity and adjustment of the surface tension of the slurry. A dispersant coating substance operative herein illustratively includes slack lime; magnesium oxide; nonionic asphalt roof emulsion; cationic or anionic asphalt emulsions, such as a road emulsion; ionic styrene butadiene rubber emulsions; neoprene containing emulsions; and combinations thereof. It is preferred that an asphalt emulsion is modified with a like pH modifier, such as a rubber for use herein. Additionally, particulate dispersing coatings are also operative to suppress electrostatic attraction between synthetic polymer particulate. Powder type dispersing coatings operative herein illustratively include water-insoluble carbonates, carboxylic acid salts, oxides and mixed oxides of metals from periodic table groups II, III and/or IV, and specifically include calcium carbonate, magnesium carbonate, barium carbonate, zinc carbonate, magnesium stearate, calcium palmitate, zinc stearate, aluminum stearate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, magnesium silicate, calcium silicate, aluminum silicate, and combinations thereof; insoluble hydroxides such as magnesium hydroxide, calcium hydroxide; magnesium phosphate, fumed silica, type F fly ash; type C fly ash; aluminum sulfate and other insoluble sulfates; and combinations thereof. Preferably, powder dispersing agent only lacks water to create a reactive dispersal. Organic polymeric dispersants operative herein illustratively include a copolymer of polyvinyl chloride with other authentically unsaturated monomers such as vinyl acetate or vinyl alcohol, acrylic resins, polyimides, epoxy resins and ionic detergents. Preferably, the dispersant coating is present from 0.125 to 0.75 pounds per gallon of synthetic polymer particulate. More preferably, the dispersant coating material is present from 0.125 to 0.50 pounds per gallon of synthetic polymer particulate.

A magnesium oxide matrix material surrounds the dispersed particulate. The matrix material is present from 0.5 to 5 pounds per gallon of dispersed particulate. Preferably, the material is magnesium oxy-sulfate. More preferably, the cementitious matrix material is present from 2 to 4 pounds of activated matrix material per gallon of dispersed particulate.

In a preferred process, dispersant coated particulate or fibers are supplied in measured bag quantities, the bagged particulate or fibers being mixed with magnesium oxide cement at the roof application jobsite. The particle or fiber containing magnesium oxide cement upon mixing is amenable to delivery to a roof substrate through pumping or conveying systems conventional to the art. The particulate or fiber material having the dispersant coated pre-applied thereto is readily wet by the magnesium oxide cement. An open-cell foam or high surface area fragmented particulate or fibers are capable of absorbing the surrounding cement matrix slurry and holding the slurry in a mass until matrix set. While the amount of particle or fiber containing magnesium oxide cement slurry applied to a roof surface is largely within the purview of one of skill in the art, typical slurry thicknesses range from one-quarter to one inch. As the slurry is spread, it forms a seamless cementitious densifying layer that seals cracks and voids associated with a substrate. Additionally, it is appreciated that such a layer has considerable adhesive tack at the exposed interface not only to cementitious substrates, but also a variety of laminate layers associated with a conventional low slope roofing system. An additional benefit of an inventive adhesive slurry is affording a fire-resistant layer without resort to the transport and handling of preformed fire-resistant boards.

An inventive intermediate layer is optionally compacted with pressure in areas of lap joints to improve the profile and decrease seam voids where one roof sheet roll overlaps a second such sheet. As the inventive adhesive is applied as a slurry, it fills in voids like pits, fractures and fastener pullouts in concrete and insulation surfaces. The inventive adhesive is optionally extruded into excessive cracks in insulation boards.

A modified version of an inventive formulation is operative to fill low areas that tend to pond water. In such a usage, preferably the particulate is of larger size with a mean particle size of greater than one-quarter inch long axis length or vermiculite. Optionally, the inventive slurry is mixed with surfactant to break the surface tension to afford a particle-rich slurry, compared to the above detailed inventive slurry amenable to wetting hydrophobic surfaces. Preferably, the higher density inventive slurry detailed above overlays this filler to ensure consistent coverage throughout the system. Water diversion from behind small curbed protrusions is also practiced in combination with the dual density adhesive provided.

An inventive intermediate layer upper surface is optionally overlayered with a non-woven fiber mat that is embedded at least in part within the matrix. A partially embedded mat serves as an adhesion surface for an asphaltic membrane layer. Preferably, the fiber mat is completely embedded within the inventive adhesive matrix such that wet cementitious slurry is exposed on the upper surface of the fiber mat, the mat affording modified mechanical properties to the adhesive. Typical fiber mats operative herein include woven and non-woven polyester, glass and polyalkylenes such as polypropylene and polyethylene.

An inventive intermediate layer is applied to roofing substrate by any roto-sater driven delivery system. This type of machine applies a ribbon or bead of an inventive slurry in a profile that is regulated by parameters such as pump speed and application wand rate of motion. Compressed air injected at the nozzle affords for even application through repetitive passes as inventive slurry is extruded and contacts a roofing substrate. In a preferred embodiment, a more controlled application apparatus is used. With an extension coupled to the applicator nozzle terminus that bifurcates from the delivery hose orifice into a manifold of smaller orifices, a more uniform and wider ribbon of an inventive slurry is applied. With the use of such a manifold applicator, an inventive slurry is readily extruded right along the top edge of a previously installed roofing membrane sheet without contaminating the lap joint of the roofing membrane sheet with a contacting second membrane roofing sheet. Additionally, it is appreciated that angling such a manifold tipped applicator wand allows for uniform delivery of an inventive slurry between spaces less than the width of the manifold. Regardless of the particulars of an inventive slurry application, upon spreading an inventive adhesive, the applied adhesive is preferably groomed to a uniform thickness through resort to a heavy roller after spreading a fiber mat and preferably a roofing membrane thereover. The roofing membrane is preferably an elastomeric water-impervious barrier layer.

It is appreciated that the lower surface of such a barrier membrane must grip an inventive intermediate layer to ensure a good bond at the interface. Membrane surfaces well suited for forming good interfacial adhesion with an inventive adhesive include styrene-butadiene-styrene (SBS) polymer modified granular surface sheets inverted and placed into contact with an inventive adhesive. Additionally, a fleece-backed surface of a polyvinyl chloride membrane affords good interfacial bonding. Preferably, conventional membrane is formed with the omission of an asphaltic layer from one side of the base ply leaving an exposed polyester fiber surface amenable to forming a good interface with an inventive magnesium oxide adhesive. Such an asphaltic layer missing membrane achieves sufficient uplift strength while providing an excellent surface for a new membrane application after roof removal. Knife cut strips of the asphaltic layer lacking membrane release with sufficient application of force to induce pull up.

Referring now to FIG. 1, a partial cutaway of an inventive roof system is depicted generally at 10. A magnesium oxide slurry 12 contains particulate and/or fibers 14 having a pre-applied dispersant coating 15 thereon to suppress electrostatic attraction and is applied to a substrate S. A woven or non-woven synthetic fiber mat 16 is optionally present. The mat 16 if present is at least partially embedded within the matrix and preferably the upper surface 18 of the fiber mat 16 is wetted with matrix material 20 that has been pressed through the mat 16. The top layer of matrix material 20 forms an interfacial bond with a lower surface 22 of an elastomeric roof membrane 24. The interfacial surface 22 of the membrane 24 illustratively includes exposed polyester fiber, an SBS modified granular surface sheet or a fleece-backed polyvinyl chloride membrane. The top surface 26 of membrane 24 is an asphaltic material or modified asphaltic surface such as that obtained by modifying the surface with SBS.

Referring now to FIG. 2, an alternative roofing system structure is depicted as a partial cutaway exploded view generally at 30. A rolled roofing material 32 has an asphaltic side 34 contacting a substrate and an exposed non-asphaltic fibrous surface 36. The asphaltic side 34 forms an interfacial bond with the substrate. While the substrate depicted in FIG. 2 is top surface 26 of the roof system depicted in FIG. 1 at 10, it is appreciated that any conventional asphalt containing surface, or surface adhesively bondable to asphalt is operative herein. The fibrous surface 36 includes a woven or non-woven synthetic fiber mat extending from an asphaltic layer 38 that terminates in the asphaltic side 34. The exposed fibrous surface 36 is porous and amenable to receive an elastomeric roof coating 40, such as conventional polyacrylic containing products. Preferably, the coating 40 is applied with a sponge roller as depicted at 42. An elastomeric roof coating 40 having a white or silver color is appreciated to provide superior reflectance and emittance values compared to heat absorptive dark colored coatings.

While a thermoset head lap or seam lap is readily applied to a membrane system in a factory process, field applied asphalt or interply adhesive is appreciated to also be operative herein. The preferred method of sealing absent factory thermoset lap formation is the injection of SBS modified asphalt at the proper transition temperature to ensure the fusion of the asphaltic side of a membrane to an exposed polyester side of a previously removed membrane layer lacking a lower asphaltic coating. SBS modified asphalt is so applied with a small rooftop kettle that fills a gravity-fed apparatus with a trigger-operated flow mechanism. Preferably, an applicator tip is designed to slide freely between the laps or the extrusion of material therebetween. Application of SBS modified asphalt to all seams followed by contact with for instance a four inch heavy roller causes fusion of the membrane while compressing the still soft but setting adhesive slurry thereby leveling the profile of the lap. A novel apparatus for application is depicted in FIG. 3 generally at 60. The apparatus 60 has a heating element 62 that melts pieces, synonymously referred to as charges, of SBS modified asphalt 64 that are inserted into an opening 66 that allows the charge to be forced past the heating element 62 under gravity feed or a pressure source. Preferably, the pieces of SBS modified asphalt 64 are size and shape matched to insert within the opening 66 and as depicted are preferably cylindrical in shape. The heating element 62 is preferably electrically powered via line power 68. The constant introduction of cold material charges 64 quickly equalizes the temperature of a reservoir 70. As such, a thermostat can be set to the rate of flow required to inject material into the laps. The reservoir 70 terminates in a tip 72 adapted to insert under a lap and fluid communication to the tip 72 under the control of a handle 74 connected to a valve 76 intermediate between the reservoir 70 and the tip 72. The applicator 60 is mounted on a wheel 78 that serves to compress just applied asphalt.

Regardless of the method used to seal lap joints between membranes overlying an inventive adhesive, the present invention achieves the following beneficial results. The membrane roll material can be applied bidirectionally so as to in theory double the rate of application by allowing an installer to turn around at an end and apply the material in the opposite direction instead of returning to the starting point as conventional factory installed laps require. Additionally, the end laps of such a membrane overlying an inventive adhesive are reversed for all rainwater flow directions for any situation such as crickets and other slope changes.

The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.

Claims

1. An adhesive for securing a roofing system to a substrate comprising:

a magnesium oxide matrix;

a plurality of particles or fibers having a dispersant coating applied thereto prior to mixing within said matrix, said dispersant coating suppressing electrostatic attraction; and

an elastomeric overlayer placed in interfacial contact with said matrix prior to set of said matrix.

2. The adhesive of claim 1 further comprising a fiber mat at least partially embedded in said matrix.

3. The adhesive of claim 1 wherein said plurality of particles or fibers are open-celled foam.

4. The adhesive of claim 1 wherein said plurality of particles or fibers are formed of a synthetic polymeric material.

5. The adhesive of claim 1 further comprising an underlying layer of magnesium oxide matrix having dispersant coated particles or fibers therein wherein the density of said intermediate matrix between the substrate and said matrix is lower than that of said matrix.

6. A process for applying a roofing system to a roof substrate comprising:

mixing proximal to said roofing substrate a quantity of dispersant coated particles or fibers with a magnesium oxide slurry to form a wet magnesium oxide matrix;

extruding said wet magnesium oxide matrix on the roof substrate; and

contacting an elastomeric membrane surface with said wet magnesium oxide matrix.

7. The process of claim 6 wherein said wet magnesium oxide matrix is applied to a thickness of from one-quarter to one inch.

8. The process of claim 6 further comprising applying a heavy roller to an upper surface opposing the membrane surface to assure interfacial contact between said membrane surface and said wet magnesium oxide matrix.

9. The process of claim 6 further comprising forming a lap joint between the opposing upper surface and a second membrane surface of a contiguous second membrane surface.

10. A roofing system comprising:

an intermediate layer having an asphaltic surface and an exposed non-asphaltic fibrous surface;

a roof substrate in adhesive contact with the asphaltic surface; and

an elastomeric outer weatherproof coating in adhesive contact with the fibrous surface.

11. The roofing system of claim 10 wherein the fibrous surface comprises a substance selected from the group consisting of: polyester, glass, and polyalkylenes.

12. The adhesive of claim 10 wherein the fibrous surface is woven.

13. The adhesive of claim 10 wherein the fibrous surface is non-woven.

14. An asphalt applicator comprising:

a molten asphalt reservoir having a base and an opening for receiving solid asphalt charges;

a heating element within said reservoir;

a tip angled to insert within a rolled roofing material lap in fluid communication with said reservoir;

a valve intermediate between said reservoir and said tip; and

a wheel external to and supporting said reservoir.

15. The applicator of claim 14 further comprising:

a thermostat coupled to said heating element.

16. The applicator of claim 14 wherein said heating element is heating by line power.

17. The applicator of claim 14 further comprising:

a handle mounting a valve controller.

18. A process for applying a roofing system comprising:

extruding onto roofing substrate a quantity of a wet magnesium oxide matrix comprising dispersant coated particles or fibers within a magnesium oxide slurry from a bifurcated nozzle from a matrix reservoir via a delivery hose;

laying and compressing a rolled sheet of membrane sheeting onto said wet magnesium oxide matrix with an applicator according to claim 14.