Permeable water-resistive sloped roof underlayment/air barrier

1. An underlayment for a roof having a slope angle of about 9.45° or more, that is an air barrier and self-adhering, vapor-permeable, water-resistive, and UV-resistant, the underlayment comprising:

a sheet of permeable plastic having a surface;

a foamed permeable copolymer coating attached to the permeable plastic's surface, wherein the foamed permeable copolymer coating includes a primary monomer n-butyl acrylate, wherein the foamed permeable copolymer is secured to the sheet of permeable plastic and has a density that ranges from 50% to 65% of the permeable copolymer coating's density before the permeable copolymer coating is foamed; and

a permeable pressure-sensitive adhesive secured to the foamed permeable copolymer coating.

2. The underlayment as claimed in claim 1 wherein the underlayment is permeable and has a permeability in the range of from about 25 perms to about 45 perms.

3. The underlayment as claimed in claim 1 wherein said pressure sensitive adhesive is placed on a silicon slip sheet and the slip sheet and pressure sensitive adhesive are laminated to the foamed permeable copolymer coating.

4. The underlayment as claimed in claim 1 wherein the permeable pressure sensitive adhesive is formed from butyl acrylate with a solid weight ranging from about 30% to about 60% of the adhesive.

5. The underlayment as claimed in claim 1 wherein the foamed permeable copolymer coating has a thickness in the range of from about 80 mils to about 100 mils and a permeability in the range of from about 30 perms to about 60 perms when cured.

6. The underlayment as claimed in claim 1 wherein the foamed permeable copolymer coating has a butyl acrylate copolymer with a solids range of about 15% to about 50%.

7. The underlayment as claimed in claim 1 wherein permeable pressure-sensitive adhesive is solvent free and the foamed permeable copolymer coating bonds with the pressure-sensitive adhesive to make a bond that is stronger than the bond that the pressure-sensitive adhesive would form with the sheet of permeable plastic.

8. The underlayment as claimed in claim 1 wherein the permeable plastic sheet is polyester.

9. The underlayment as claimed in claim 1 wherein the permeable pressure-sensitive adhesive has a thickness in the range of from about 4 mils to about 6 mils.

10. The underlayment as claimed in claim 1 wherein the foamed permeable copolymer coating contains about 1% carbon black by weight.

11. An underlayment for a roof, that is an air barrier, water-resistant, vapor-permeable, and self-adhering, the underlayment comprising:

a base substrate of permeable polyester having a surface,

a foamed, permeable acrylate coating attached to the polyester substrate's surface, wherein the foamed, permeable acrylate coating has a thickness in the range of from about 80 mils to about 100 mils, and has a density in the range of from 50% to 65% of the permeable acrylate coating's density before the permeable acrylate coating is foamed; and

a pressure-sensitive, permeable layer of acrylate adhesive bonded with the foamed, permeable acrylate coating and having a thickness in the range of from about 3 mils to about 20 mils; and

wherein the combination of the substrate, the coating, and the adhesive has a permeability in the range of from about 25 perms to about 45 perms.

12. The underlayment as claimed in claim 11 wherein the pressure-sensitive adhesive is placed on a silicon slip sheet and the slip sheet and pressure-sensitive adhesive are laminated.

13. The underlayment of claim 11 wherein the roof has a pitch of at least 9.45°.

14. The underlayment of claim 11 wherein the underlayment is capable of supporting a water column at least 24 inches high for at least 48 hours.

15. The underlayment of claim 11 wherein the permeable, pressure-sensitive adhesive has a removable silicon release film mounted thereto to form an exterior surface of the underlayment.

16. The underlayment of claim 11 wherein the foamed, permeable acrylate coating contains about 1% of a UV blocking material.

17. The underlayment of claim 11 wherein the foamed, permeable acrylate coating contains n-butyl acrylate having a solid weight in the range of from about 20% to about 55% by weight of the coating.

18. An assembly for a roof, that is an air barrier, water resistant, UV resistant, vapor permeable, and self-adhering, the assembly comprising:

a substrate of vapor-permeable polyester having a surface;

foamed, vapor-permeable acrylate coating bonded to the surface of the permeable polyester substrate, the vapor-permeable acrylate coating being a copolymer including a polymer of n-butyl acrylate and containing carbon black;

a vapor-permeable, pressure-sensitive, permeable copolymer adhesive secured to an outer side of the vapor-permeable acrylate coating; and

wherein the combination of the substrate, the coating, and the adhesive has a permeability in the range of from about 20 perms to about 40 perms.

19. The assembly as claimed in claim 18 wherein the coating has a thickness in the range of from about 80 mils to about 100 mils and the permeable pressure-sensitive adhesive has a thickness in the range of from about 3 mils to about 10 mils.

20. The assembly as claimed in claim 18 wherein the assembly has a walkable surface and a UV resistance of up to 4 months.