CentiMark Corporation (est. 1968) is a national roofing contractor company headquartered in Canonsburg, Pennsylvania in the United States. The company also has a flooring division, QuestMark, and a Canadian Roofing subsidiary, CentiMark LTD. Edward B. Dunlap started D&B Laboratories in 1967 as a part-time industrial cleaning products business in the basement of his home. In 1968, with $1,000 seed money from D&B Laboratories and one associate, Dunlap started Northern Chemical Company. In response to customer needs, Northern Chemical Company became involved in roofing and flooring maintenance. In the 1970s, the oil crisis negatively impacted the built-up roofing market that was dependent on crude oil for asphalt. The quality of asphalt decreased as oil companies were pressed to extract as much oil from crude as possible. The price of asphalt increased, thus resulting in higher roofing prices. Concerned about the quality of bituminous materials used in built-up tar and asphalt roofs, Northern Chemical Company began marketing and installing single-ply rubber (EPDM) roof systems. The newly developed EPDM polymer was both durable and waterproof. It was a cost-effective solution to the increasing costs associated with built-up roofing. In the late 1970s and early 1980s, EPDM was one of the fastest growing roofing products and accounted for almost 40% of new and replacement roofs on commercial and industrial properties.