Built-Up Roofing is one of the oldest roofing methods still currently in use throughout the world. For more than 120 years, built-up roofs have been protecting the interiors and maintaining the integrity of low-slope rooftop buildings. Why? Because the concept is undeniably sound, and while modernization in terms of materials has occurred, the steps for successful installation are very much as they’ve been for a century and more. Built-Up roofing systems consist of layers of material such as felt, mat, or fabric that are saturated with bitumen, coal tar pitch, or asphalt. This building up of waterproofing gives these systems the weatherproofing and temperature resistance important to all roofing, but with the advantage of being less expensive.