Fiber mat, method of making the fiber mat, and bituminous roofing product

A method of making a fiber mat comprises:

• providing an assembly of fibers comprising a minority portion comprising a set of polymer fibers and a majority portion comprising a set of fibers different than the minority portion, wherein the minority portion is a plane parallel to a plane of the majority portion of the assembly of fibers;
• applying a binder to the assembly of fibers, wherein the binder comprises an organic resin;
• and
• curing the binder, wherein an air permeability of said fiber mat is not substantially different from an equivalent weight fiber mat containing a homogenous mat structure and wherein the fiber mat provides at least a 5% increase in tear when placed in a bituminous roofing product compared to an equivalent bituminous roofing product made with the equivalent weight fiber mat containing the homogenous mat structure.