Foamed fiber compositions and processes of making said compositions. Compositions include a hydraulic mixture including (i) a polymer and (ii) one or more of gypsum, fly ash, and cement; and a foam including a foaming agent, a foam stabilizer, and 0.5-35% fibers by weight. The process for forming the foamed fiber composition includes providing a stable foam including a foaming agent and a foam stabilizer; mixing fibers into the stable foam until the fibers are uniformly distributed in the foam to form a fiber-containing foam, wherein the fiber-containing aqueous foam contains 0.5-35% fibers by weight; and mixing the fiber-containing foam into a hydraulic slurry including (i) a polymer and (ii) one or more of gypsum, fly ash, and cement. The composition is suitable for use in roof tiles, underlayments, backerboards, cement composites, foam fills, bricks, cement sidings, etc.