Elk Corporation     “Elk Corporation has merged with GAF Materials Corporation, North America’s largest roofing manufacturer. GAF-ELK now offers a new and improved product line which can be found at: www.gaf.com.”     http://www.gaf.com/General/GafMain.asp?Silo=DECKRES&WS=GAF&Force=../../../../Content/GAF/DECKRES/railways.html