The hanging systems for vinyl gutters are under more stress than those for metal systems due to the high coefficient of expansion in PVC. The lateral motion of the guttering can cause non rigid brackets to twist and bind the gutter, and in some cases the brackets can act like a ratchet allowing the gutter to move in only one direction. This restriction can result in the bowing of the gutter, failure of the bracket, or tearing out of the screws. Plastmo uses a very rigid bracket with carefully engineered placement of the mounting screws to resist any bracket movement and allow free gutter travel. Unlike the British type gutter systems marketed in America Plastmo brackets are engineered to withstand heavy snow loads. A person should always consider the above criteria before purchasing a vinyl gutter system.