A method of making a glass mat includes providing an assembly of glass fibers, applying a binder composition to the assembly of glass fibers, wherein the binder includes an organic resin, and curing the binder composition while dimensionally constraining the assembly of glass fibers. Dimensional constraining includes directly contacting a first major surface and a second major surface of the assembly of glass fibers between two substantially parallel surfaces. Further provided is a glass mat that includes an assembly of glass fibers, wherein the assembly of glass fibers are substantially randomly oriented with a tensile anisotropy of less than about 6 in any two directions. The glass mat has a decreased surface roughness and a decreased caliper compared to an equivalent glass mat having an assembly of naturally packed glass fibers with an equivalent fiber diameter size.