General Roofing Mfg. Co. · General Roofing Mfg. Co. · leaf 6
of thecoal as a gas. Thenas the gas cools, thetar is condensed intoliquid form. Whenused in roofing, it driesout, becomes brittle,and in a comparativelyshort time loses its life,it dries out rapidly. Asphalt, the basis of Certain-teed Roofing, is ablend of mineral asphalt and mineral asphalt… … Approved methods for importantcity structures Being of a gaseous nature,
Architecture, Domestic · Designs and plans
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