How to tell what type of roof you have on your house
A roof’s primary purpose is to protect a building and its occupants from rain, snow, sun, wind and other elements. However, roofs are not intended to keep out the cold. In fact, most roofs are very poor insulators.
There are two main types of roofs: sloped roofs and flat roofs.
Sloped roofs have tilted planes so they shed water and debris. They are not watertight. Flat roofs are watertight membranes. They should have a slight slope so they drain water effectively.
Most homes in this area have sloped roofs. They are usually covered with asphalt shingles or wood shingles/shakes.
Asphalt shingles are the most common roofing cover. Their base is made of felt paper or fiberglass coated with asphalt and covered with granular material.
Wood shingles are machine-cut, while wood shakes are split mechanically or by hand. Wood shakes also are thicker and have a much more uneven surface. Most wood shingles are made from cedar, but some are redwood.
Other types of roof coverings include:
- Slate shingles.
- Concrete and clay tiles.
- Fiber cement shingles.
- Metal roofs.
- Corrugated plastic roofs.
- Built-up roofs.
- Roll roofing.
- Modified bitumen.
Roofing wear and tear
Asphalt shingles generally last from 10 to 35 years, depending on the weight of the shingle and the pitch of the roof. The steeper the roof, the longer the shingles will last.
The granular covering on shingles protects them from ultraviolet light. As the granules wear off, the shingles dry out and become brittle; they can also crack, buckle and curl.
Lighter colored shingles reflect more light and may last slightly longer than darker shingles. Roof areas that face south and west may wear out faster than other areas.
Wood shingles and shakes may last 30 to 40 years. This can vary greatly, however, depending on these factors:
- The amount of shingle exposed to weather.
- The pitch of the roof (steeper is better).
- The quality of the shingle.
- The amount of sun and shade on the roof. Too much sun dries out the shingles and makes them brittle. Too much shade helps the shingles retain moisture, leading to growth of rot and mold.
Leaks and other problems are likely to happen in areas of the roof where the roof changes direction, or there is a change in materials, such as where the roof meets a chimney or a wall. These areas are protected with flashings: sheets of galvanized steel, aluminum or other material. Flashings are placed in joints, peaks and around chimneys or other openings to prevent water seepage.
Other vulnerable areas include places where:
- TV antennas or satellite dishes are attached.
- The slope of the roof is low.
- Repairs have previously been made.
- Tree branches touch the roof, wearing down shingles prematurely.
Ice damming on roofs is also a concern in this area of the country. These dams form when snow and ice collect in an area of the roof — usually the eaves. The dams block melting snow from running off the roof. The water collects behind the dam until it backs up under the shingles and leaks into the eaves or — even worse — into the walls.
Ice dams can be prevented by increasing attic insulation and attic ventilation. These will lower the air temperature in the attic so snow won’t melt over the heated portions of the house and roof.