According to professional roofing manufacturers, white membrane single ply roof systems should be washed at least once a year. Over time, UV rays and excessive heat will break down the roofing material faster than anything else. Pressure washing is an excellent way to ensure that you get the ultimate reflectivity and a cooler substrate to reduce the degradation of your roof and extend its lifespan.
Membrane roofs are bright white because the white color reflects the most radiant heat and UV rays. When the membrane becomes riddled with dirt and debris, however, it cannot perform as it is supposed to. When you allow dark algae to build on the surface you not only decrease the energy efficiency of your roofing material; you shorten its lifespan. By having your commercial roof cleaned regularly, you will increase its overall lifespan and get the most energy efficiency possible.