Fire-resistant roof system and membrane composite

1. A method of forming a roof system, the method comprising:

(i) providing a first membrane composite that includes a thermoplastic membrane layer having first and second planar surfaces, and a fabric backing heat welded to a portion of said first planar surface of said thermoplastic membrane layer, where the fabric backing includes a fabric substrate having first and second planar surfaces, a coating layer disposed on the second planar surface of the fabric substrate, and where said first planar surface of the fabric substrate is attached to the thermoplastic membrane layer, said coating layer including expandable graphite expanded to at most 10% beyond its original unexpanded size dispersed within a binder, where said first membrane composite is in the form of a roll;

(ii) unrolling the first membrane composite over a first portion of a roof surface such that the fabric backing directly contacts said first portion of a roof surface;

(iii) mechanically attaching the first membrane composite to the first portion of the roof surface;

(iv) providing a second membrane composite that includes a thermoplastic membrane layer having first and second planar surfaces, and a fabric backing heat welded to a portion of said first planar surface of said thermoplastic membrane layer of said second membrane composite, where the fabric backing of said second membrane composite includes a fabric substrate having first and second planar surfaces, a coating layer disposed on the second planar surface of the fabric substrate, and where said first planar surface of the fabric substrate is attached to the thermoplastic membrane layer, said coating layer including expandable graphite expanded to at most 10% beyond its original unexpanded size dispersed within a binder, where said second membrane composite is in the form of a roll;

(v) unrolling the second membrane composite over a second portion of the roof surface and adjacent to the first portion of the roof surface upon which the first membrane composite is attached such that the fabric backing directly contacts said second portion of the roof surface;

(vi) seaming the second membrane composite to the first membrane composite; and

(vii) mechanically attaching the second membrane composite to the second portion of the roof surface.

2. The method of claim 1 , where each coating layer includes at least 2 wt % expandable graphite dispersed within a polymer binder.

3. The method of claim 1 , where each coating layer includes at least 8 wt % expandable graphite dispersed within a polymer binder.

4. The method of claim 1 , where the roof surface is a wood deck.

5. The method of claim 1 , where each thermoplastic membrane layer is a thermoplastic polyolefin.

6. The method of claim 1 , where each fabric substrate is a polyester fleece.

7. The method of claim 1 , where each fabric substrate is a fiber glass mat.

8. The method of claim 1 , where said roof system achieves a class A rating pursuant to UL 790 and/or ASTM E 108.

9. The method of claim 1 , where the roof surface includes a wood deck and an insulation layer disposed over the wood deck.

10. The method of claim 1 , where the fabric backing of the first membrane composite is attached to the portion of the first planar surface of the thermoplastic membrane layer of the first membrane composite in a manner that provides at least one lap edge where the first planar surface of the thermoplastic membrane layer of the membrane composite is exposed.

11. The method of claim 10 , where the fabric backing of the second membrane composite is attached to the portion of the first planar surface of the thermoplastic membrane layer of the second membrane composite in a manner that provides at least one lap edge where the first planar surface of the thermoplastic membrane layer of the second membrane composite is exposed.

12. The method of claim 11 , wherein during unrolling of the second membrane composite, the lap edge of the second membrane composite overlaps a portion of the first membrane composite.

13. The method of claim 12 , wherein the step of seaming the second membrane composite to the first membrane composite occurs along the lap edge of the second membrane composite.