By Peter J. San Juan, Koppers Inc.
Coal Tar Pitch built-up roofing (BUR) systems consist of alternate layers of coal tar pitch and reinforcing felts, topped with a pouring of coal tar pitch into which an aggregate surface is embedded. Coal tar built up roofing systems are used on all level or low sloped roof, and whenever the roofing membrane will be expected to pond or hold water. Slopes for coal tar pitch roof systems may be up to ¼” per foot for Tar-glas systems and up to ½” per foot for organic reinforced systems.
Coal Tar built up roofing provides one of the most durable roofing systems known due to its inherent waterproofing and weathering characteristics. An independent study completed in 1996 by Carl Cash of Simpson, Gumpertz & Heger Inc. showed that coal tar pitch roofing systems has not only the highest durability of any membrane roofing system on the
market today (average of 22.5 years) but also the lowest life cycle cost and the highest percentage of roofs surviving after 30 years.
Coal Tar Built Up Roofing Systems provides numerous advantages to an owner:
Coal tar has a natural resistance to water. A tight molecular structure enables coal tar to resist water penetration, oxidation of the roof surface as well as resistance to many of the common chemicals found in today’s environment.
Coal tar roofing is self-healing. Alligatoring and hair line fissures common to most materials eventually allow damage to the roofing membrane. Coal tar has a property known as “cold flow” which acts to correct or lessen these conditions. This cold flow feature permits the roof to slowly heal hairline fissures and alligatoring when roof temperatures reach necessary level for “cold flow” to take place.
Coal tar roof systems require aggregate in all applications. Aggregate provides superior protection from foot traffic, fire protection form burning brands and additional protection from wind up-lift. Nature has provided coal tar with the correct chemical and physical characteristics for resistance to degradation from all of the most menacing atmospheric conditions, combined with long term durability against one of the most devastating of nature’s solvents – water – in all of its forms. Coal Tar roofing systems are time-proven roofing systems for level and low sloped roofs. To find out more about Coal Tar pitch built up roofing systems contact Koppers Inc. at 800 558-2706.
