Founded in 1979, Gypsum Supply Co. Inc. is the largest supplier of drywall and plaster products in the Western Michigan. Based in Lansing, Mich., it offers a range of products, such as drywall, plaster, acoustical ceilings and grid, steel framing and insulation. The company caters to building contractors for commercial projects, apartments, new homes and remodeling. Gypsum Supply Co. Inc. is a member of the Association of the wall and ceiling industry (AWCI) and National Association of Home Builders.