How to Extend the Life of Your Roof

The biggest factors in the lifespan of a roof are the quality of the materials and workmanship when the roof is put on. Metal roofs and tile roofs can last twice as long as asphalt shingle roofs, but they also cost more to install.

Workmanship also is a factor because there are so many opportunities to do the job badly or skimp on materials.

If you're buying a house, make sure you have the roof inspected and find out from the seller what year the roof was put on.

For the homeowner, the primary roof maintenance responsibilities are:

Keep the gutters clean to prevent unnecessary water damage to the lower deckboard, and the fascia and soffit boards along the gutter line.

Remove debris from the roof such as tree branches and leaves that may collect along roof valleys.

Watch for ice dams that may develop in winter when snow on the roof is partially melted.

Have the roof professionally inspected every two or three years and have small repairs made as needed -- such as resealing weak spots that may begin to develop along the flashing.

Poor attic ventilation can cause a number of problems -- including premature aging of the roof.

During the summer months, the temperature in an attic without proper airflow can hit 160 degrees. Such superheated air can penetrate attic insulation, making it harder to keep the home cool and even damaging wallpaper and paint on the floor directly below.

Up on the roof it can "fry" your shingles, making them decay more quickly -- and the rafters holding up the roof can be weakened by warping and cracking.

In the winter, various household appliances, bathtubs, showers and cooking vapors can contribute to excess moisture build up. Improperly ventilated attics will allow this moisture to collect and cling to the underside of the roof.

There, it will condense and fall, soaking the attic insulation and reducing its efficiency.

Air circulation in the attic is based on a balance between air intake vents in the soffits and air exhaust at or near the roof's peak.

The Federal Housing Administration recommends a minimum of at least 1 square foot of attic ventilation (both intake and exhaust) for every 300 square feet of attic space.

For example, if your attic is 900 square feet, you need a total of 3 square feet of ventilation. This amount is generally divided equally between intake and exhaust ventilation to ensure proper air flow through the attic.

When we think of insulation, we usually think of materials placed in attics, walls and crawl spaces that retard heat transfer and help keep our houses and offices cooler in summer and warmer in winter.

Insulation can also protect the structural components and integrity of a building. Insulating a roof not only helps reduce energy bills and provides comfort for those inhabiting the space below, it also extends the life of a roof.

Temperatures on roofs can rise up to 90 degrees higher than ambient air temperature. When exposed to sunlight in warm climates, roofs transfer radiant heat to the surfaces of objects below in attics and buildings.

Insulating attic spaces with radiant barriers and reflective insulation reduces transfer of radiant heat, reflecting it back to the roof. This decreases the temperature within the structure.

Roof insulation can be applied to existing roof systems. Particular materials are suited for different types and slopes of roofs, including steep-sloped, low-sloped and flat. Insulation materials include latex and acrylic barriers, bituminous asphalt, elastomeric (non-bituminous) coatings, fibered coatings and polystyrene or rigid foam panels.

When a new roof is required, white or light-colored materials provide thermal insulation, reduce roof temperatures and prolong the life of a roof. Traditional roof materials like clay tiles and shingles are now available in reflective materials that reduce thermal transfer and promote solar reflection.

Asphalt shingle roofs that are in constant shade tend to attract algae growth, which feeds off of microscopic particles in the limestone used in the shingles. This growth can be seen as a black or dark green staining on the roof and many homeowners are eager to get rid of it.

Roof cleaning isn't harmful if done professionally, and many homeowners value the aesthetics of a clean roof. However, some people believe it does not add to the longevity of a roof.

The argument for roof cleaning states that it improves the curb appeal of a home, and protects the shingles, which ultimately extends the life of a roof. It's also believed to improve energy efficiency because a darker roof will generate more heat.

Editor's Note: The article was originally published Oct. 24, 2015.