Roofing Materials and Resources

• Traditionally roofs have been covered with materials at hand. Rushes and grass, woven or tied together, were early natural materials used to cover homes; in some areas thatch still keeps homeowners dry. Builders in areas that were heavily forested used wood "shake" shingles, broken from the stumps of trees cut for lumber.
  
  Clay from local soils became the basic material for bricks, simple clay shingles and the clay tiles that grace the roofs of Mediterranean and Southwestern U.S. buildings. Composition or "asphalt" shingles are actually a fairly new invention and have been used only since the early part of the 20th century when Henry Reynolds cut a roll of asphalt-soaked felt roofing into single pieces. By the 1930s Reynolds' invention was being marketed in various shapes and colors but was still basically the same material. Asbestos was used as a base until its dangers became common knowledge and, beginning in the 1970s, fiberglass was substituted for felt in many shingles to improve fire resistance.
  
  Today, shingles are sometimes fabricated using organic felt made from recycled wood or paper products. In a global economy any material is available and homebuilders chose a roofing material based on design and the homeowner's budget rather than what's available locally.
  
  

Application

• A 500-year-old clay tile roof with lead flashing.
  
  Clay tiles came into common usage during the Middle Ages. They are much heavier than composition shingles and extra bracing often must be added to support a clay roof. This is often not a problem on large older homes that were built with more structural support.
  
  Composition tiles are easier to apply requiring a layer of felt and coming in convenient long pieces detailed to look like three or more shingles; clay tiles must be attached one at a time over the felt. Tile also is a bit tricky to handle; it can be brittle and must be carefully nailed using pre-molded holes. Although the initial expense of tile may be four to six times as much as composition roofing, the life of a clay roof is often 70 to 90 years while asphalt must be replaced every 10 to 15 years, making the clay comparable in cost, providing the homeowner (or his descendants) stays in the house long enough.
  
  

Uses

• Each clay tile must be individually fitted and attached.
  
  Composition shingles are popular --- they cover more than 80 percent of modern roofs. Asphalt is a proven technology after a century and a half of use and is produced today in forms that mimic the effects of clay and cement shingles without the weight or cost. Tile is available in a modest range of shapes and colors but has the added advantage of being fireproof and better insulating --- important in hot, sunny climates.
  
  Clay tile is made much as it was in history and is acceptable for restoration for a wide range of historic houses and styles. Asphalt roofing has fewer historic applications but some companies are manufacturing reproductions of the old diamond and overlapping key patterns popular in the 1930s and 40s.