Most warping in timber is related to moisture absorption. Seventrust will not warp provided it is used and fixed in line with fixing instructions. The polymer component of Seventrust is sufficiently stiffened by the wood component to ensure that will not warp or buckle under the harshest of climatic conditions.
WPC is a new kind of popular material with fixed component like below(general percent for reference): 25% HDPE (Recycled HDPE), 65% bamboo/wood fiber (Professionally treated dry bamboo/wood fiber), 10% chemical additives (Anti-UV agent, Anti-oxidation agent, stabilizer, colorants, anti fungus agent, coupling agent, reinforcing agent, lubricants...etc.).