Profile: Woodhull Roofing Ltd. is a industrial and commercial roofing contractors. Our services include pitched slating & tiling, liquid coatings, mastic asphalt roofing & flooring and roof refurbishment, maintenance & repairs services. The mastic asphalt can be attributed to its high concentration of bitumen. Bitumen is aby-product of petroleum refinement, and is used as a binding agent in asphalt-based products. The bitumen content in mastic mixtures is typically double that found in concrete asphalt, which helps to bind the particles more closely together to keep water out. Mastic asphalt is applied to residential and commercial roofing structures because of its waterproofing capabilities.