Historic Marker number 99 is located at 718 Southard Street between William and Elizabeth Streets.Roofs in the historic district are predominantly covered with metal. The silver metal roofing material is not a style or a fad left over from the 1800s, but a practical response to a real problem. Key West started out as an industrial city where wooden structures were built in close quarters. Roofs were made of wooden shakes, which were a readily available material and cost efficient. They were also highly flammable.With nothing but dry wooden structures in front of it, the Great Fire of 1886 consumed two-thirds of Key West's buildings (For more, see Historic Marker # 28).In an effort to prevent future fires, the City required metal roofs on new and replacement buildings in what is now the Historic District. There are four main styles of metal roofs commonly seen in Key West. There are roofs with metal shingles were 6"x6"squares of galvanized steel stamped with a raised pattern that were hooked together and nailed at the edges. The Historic District also includes roofs with 4'x6' sheets of metal that are stamped to resemble metal shingle roofing. The panels were overlapped and secured by nails with a lead washer to seal the nail hole. Another style of metal roofing in the Historic District is two foot wide, flat galvanized panels that run from the roof ridge to the eave end of the roof. The panels overlap and are secured to the roof with screws and rubber washers. A relatively modern steel protection treatment is coating galvanized metal with an additional coating of aluminum. The process is called galvalume.While metal roofing is more expensive than wooden shakes it has a number of advantages. Property insurance costs were reduced on buildings with metal clad roofs due to their fire resistance and indirect advantage of acting as a fire barrier for interior fires. The most significant advantage is the cooling affects the light colored material has in Key West's subtropical climate. When sunlight and ultraviolet light shine on silver colored metal roofs, much of it is reflected and passes back through the atmosphere into space. Light colored metal roof buildings are, on average, 15% cooler than structures with dark roofs.Metal roofs also hold up well in hurricanes and have a 60 year lifespan if maintained.