A sizing composition for reinforcement fibers that includes one or more film forming agents, a silane coupling agent package, and at least one lubricant surfactant is provided. Optional components such as rheology modifiers, fillers, biocides, and pH modifiers may also be included. Preferred film forming polymers are amide-based polymers. Additionally, the sizing composition is free of polyvinyl alcohol. The absence of polyvinyl alcohol in the size composition reduces or eliminates the production of precipitates from white water in wet-laid processes. The size composition is applied to reinforcement fibers and formed into chopped strand, wet-laid mats that can be used for a variety of purposes, including roofing products. Chopped strand mats formed from fibers sized with the inventive sizing composition maintains or improves the dry tear and tensile strengths compared to chopped strand mats made from fibers sized with a commercial sizing composition that does not contain polyvinyl alcohol.