Cleaning is an important part of roof maintenance that is often overlooked. Periodic roof cleanings will extend the life and protect the appearance of your roof. Flat and low-slope roofs can collect dirt and debris. Sloped roofs with surface grit, ridges, channels, and/or gutters can also collect dirt and debris. Dirt and debris can hide damage and can wear down roof membranes and bitumen surfaces by retaining heat and moisture.