Composite mat product for roofing construction

1. Water-resistant roofing construction comprising a non-asphaltic, non-cellulosic, flexible, air and water-vapor-permeable composite mat product comprising (a) a glass mat of glass fibers of about 3 to about 20 microns in diameter and of about 0.25 to 1.75 inch in length, and a mat thickness of about 10 to about 30 mils, surfaced or coated on both sides with (b) a cured natural or synthetic thixotropic polymer latex foam coating, wherein the cured natural natural or synthetic thixotropic polymer latex foam coating comprises between 15 and about 80 wt. % of a foamed mixture containing, on a dry weight basis, between about 15 and about 80 wt. % of said polymer latex, between about 0.01 and about 80 wt. % of a mineral filler, and between about 0.5 and about 10 wt. % of a foam supporting surfactant, the density of the foam coating being about 0.15 to 2 g/cc, wherein the consistency of said foam assures that it does not penetrate through the mat, and the amount of air incorporated into the foamable mixture prior to coating is between about 5 and about 80% by volume, and the resulting foamed mixture has bubble openings sufficiently small so as to inhibit liquid bleed through the mat, inter-layered between a weathering course and structural decking, which is permeable to both air and water vapor so that both can escape through the mat and its coatings.

2. Water-resistant roofing construction according to claim 1 wherein the weathering course is a shingle and the structural decking is plywood.