A thermoplastic composite sheet for exterior cladding applications includes an outer layer with a thermoplastic resin composition reinforced with a high aspect ratio filler such that the outer layer has a coefficient of linear thermal expansion of no more than approximately 2.33×10−5 in/in/deg F., and a backing layer bonded to the outer layer, the backing layer defined by a foam material. The outer layer and the backing later define a body having a substantially planar outer surface.