What Roofers Do
Roofers repair and install the roofs of buildings using a variety of materials, including shingles, asphalt, and metal.
Roofers typically do the following:
- Inspect problem roofs to determine the best way to repair them
- Measure roof to calculate the quantities of materials needed
- Replace damaged or rotting joists or plywood
- Install vapor barriers or layers of insulation
- Install shingles, asphalt, metal, or other materials to make the roof watertight
- Align roofing materials with edges of the roof
- Cut roofing materials to fit angles formed by walls, vents, or intersecting roof surfaces
- Cover exposed nail or screw heads with roofing cement or caulk to prevent leakage
Properly installed roofs keep water from leaking into buildings and damaging the interior, equipment, or furnishings.
There are two basic types of roofs, low-slope and steep-slope:
- Low-slope: About two-thirds of all roofs are low-slope. Most commercial, industrial, and apartment buildings have low-slope roofs. Low-slope roofs rise 4 inches or less per horizontal foot and are installed in layers.
For low-slope roofs, roofers typically use several layers of roofing materials or felt membranes stuck together with hot bitumen (a tar-like substance). They glaze the top layer to make a smooth surface or embed gravel in the hot bitumen to make a rough surface.
An increasing number of low-slope roofs are covered with a single-ply membrane of waterproof rubber or thermoplastic compounds.
- Steep-slope: Most of the remaining roofs are steep-slope. Most single-family houses have steep-slope roofs. Steep-slope roofs rise more than 4 inches per horizontal foot.
For steep-slope roofs, roofers typically use asphalt shingles, which often cost less than other coverings. On steep-slope roofs, some roofers also install tile, solar shingles, fiberglass shingles, metal shingles, or shakes (rough wooden shingles).
To apply shingles, roofers first lay, cut, and tack 3-foot strips of roofing over the entire roof. Then, starting from the bottom edge, they nail overlapping rows of shingles to the roof.
A small but increasing number of buildings now have “green” roofs that incorporate landscape roofing systems. A landscape roofing system typically begins with a single or multiple waterproof layers. After that layer is proven to be leak free, roofers put a root barrier over it, and, finally, layers of soil, in which vegetation is planted. Roofers must ensure that the roof is watertight and can endure the weight and water needs of the plants.
Source: Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, 2012-13 Edition