A fiber mat includes a unitary assembly of fibers including at least a first set of fibers and at least a first binder comprising an organic resin, wherein the unitary assembly of fibers includes a minority portion and a majority portion different than the minority portion, 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 a fiber mat of equivalent weight containing a homogenous mat structure.