Abstract: An exterior insulating sheathing which comprises a foam polystyrene ply and a second ply glued to said polystyrene ply throughout. The second ply is preferably a fiberboard but may also be a waferboard. The sheathing is nailable, has a racking load of about 1900 to 3700 lbs, and has at least he exposed side of the second ply water resistant. This sheathing has a minimum tensile strength of 65.+-.14 kPa, a linear expansion at 97% RH and 23.degree. C., of less than 0.40%.+-.0.02, a water vapor transmission of at least 96.sup.ng.Pa.s.m.sup.2, and a modulus of rupture of 0.5 to 17.2 megaPascal.

Abstract: A wood substrate having good flame resistance characteristics while substantially maintaining its adherence characteristics for asphalt products. One surface of the wood substrate has a coating of an inorganic soluble silicate impregnating the wood substrate and forming a firm bonding with it. A process which is disclosed comprises: (a) coating at least one surface of a wood substrate with a concentrated solution of an inorganic soluble silicate, and (b) drying said coating as to leave on said surface the inorganic silicate impregnating the wood substrate and form a firm bonding with the wood substrate.