Common Commercial Roofing Problems

NRCA exec: What homeowners need to know about roof replacement

October 12, 2014

Replacing a roof requires a look beyond the surface, advised William Good, executive vice president of the National Roofing Contractors Association. Replacing a steep-slope roof may include the underlayment, sheathing, rafters, trusses or flashing. For instance, clay tiles may require roofing trusses to be strengthened to support their weight on the roof.

Most of us have heard the phrase “keeping a roof over our heads.” For many homeowners, that’s a literal concern. Household roofs experience weathering, falling debris, and wind or water damage. A roof may leak and require better insulation; supports might need replacing. Or a homeowner could want a new roof for purely aesthetic reasons.
Owens Corning, a well-known manufacturer of building products, offers some indications that your roof may need repair or replacement:
  • Shingle edges are curled or shingle tabs are cupped, bald or cracked.
  • Your roof is at least 20 years old, or other homes in the area that were built at the same time need roof repair.
  • The roof looks worn, has dark (algae) streaks or has moss growing on it. Moss and algae can be removed, but it’s best to contact a professional contractor to avoid damage. When choosing new roof materials, consider the slope (pitch) of the roof, sun exposure, local temperature, weather, storms and yearly climate. (Roofs with 25-percent slope or more are considered pitched.)
  • Check for local ordinances and building and fire codes.

On average, a new roof costs a homeowner anywhere from $7,000 to $36,000 without structural repairs or modifications, and the life expectancy and durability of the material should be considered. Thanks to newer technology, many of the roofing materials that previously were not considered flame retardant are now treated to increase safety. According to William A. Good, executive vice president of the National Roofing Contractors Association, all steep-slope roof systems have basic components: shingles, tile, slate or metal and the underlayment that protects the sheathing from weather; sheathing (boards attached to rafters to cover a house), rafters and trusses to support the sheathing; flashing used at joints to prevent leaks; and the roof’s ability to shed water. Depending on the roof’s age, the existing material and the reason for the repair, a partial re-roofing could be an option. While this may save money in immediate materials, there are other considerations.

There are limits to the layers on the roof, and this might not expose problems with the sheathing or underlayment, and new and old color lots may not match. Consider both your short- and long-term savings and needs. Think about regional influences and budget when deciding on materials.

The most common and generally the least expensive pitched roof cover is the asphalt shingle, also called composition shingles. Asphalt shingles are made with fiberglass, asphalt and tiny embedded stones that help protect the roof from the sun’s damaging rays. These roofs have an average life span of 15 to 20 years. The architectural asphalt shingle is a heavier version with fewer crevices for debris that lasts approximately 30 to 50 years. Clay tiles come curved or flat, color-glazed and in a variety of surface textures. A clay tile roof could last as long as 100 years with low maintenance requirements and increased fire protection. Drawbacks to clay tiles include weight, which may require reinforcing roof trusses, fragility (they can break or chip if walked on or hit by tree branches) and cost. Concrete tile is generally composed of cement, sand and water and is also very heavy. These tiles have a long lifespan of 30 to 40 years and are low maintenance and durable. Normally a class-A fire-rated roofing system, concrete tile is durable enough to walk on, energy-efficient and a natural insulation to noise. Recyclable metal roofing materials include steel, aluminum, copper and alloy strips. Metal is fire-resistant, lightweight, nearly maintenance-free, energy efficient and durable — lasting 50 to 75 years. Natural slate stone is fireproof and waterproof and is frequently used in historic homes. It requires little maintenance and has a long life span of up to as many as 200 years. Like clay tile, slate is a very heavy material. Metal and slate are among the most expensive of all roofing materials. Synthetic slate (rubber composite) is lighter and less expensive than natural stone and is made from recycled materials. It will last 40 to 60 years and is practically maintenance-free. Wood shakes are resistant to rot, treated to be fire retardant and with proper maintenance will last as long as 30 to 50 years.


Weak Roofing Material Demand Lowers Owens Corning's 2014 Outlook