Never let weeds and debris building up on your roof. RRCL was recently on a conventional roof with a built-up roofing membrane and saw all these weeds! It was akin to a small forest! When weeds take root in your membrane cover (in this case it was loose crushed stone) they will shoot roots down towards your roof membrane. As the weeds grow, so do the roots! This increases the potential for damage to your roof membrane. If you need some advice on your roofing, RRCL has over 20 years of expertise in roof design and replacement.