When the National Park Service installed a new slate roof on Arlington House, the Robert E. Lee Memorial, Virginia, in 1991, it approached the job as an integrated system involving roof framing, deck, underlayments, flashings, ventilation, gutters, and drainage. Carefully selected building materials included 45 mil ethylene propylene diene monomer membrane for critical portions of the underlayment, 20-ounce lead-coated copper for flashings and gutters, lead wool packing and copper nails for attaching the flashing, copper slating nails, and 5/8 inch CDX plywood for the nailing bed.