Kulp's of Stratford provides residential roofing, commercial roofing and spray foam insulation throughout Wisconsin. Experience Much More Than a Great Roof! Kulp's of Stratford, along with its sister company, Marathon Metals, is a roofing, insulation, and sheet metal contractor in Central Wisconsin. We provide premium products and top quality installation and repair services to commercial, industrial, religious, and residential clients in Wisconsin and the upper peninsula of Michigan.