Thursday, December 3, 2009


Cost and aesthetics may be your first thoughts when selecting your roof but there are many other factors to consider especially in our hot, humid, hurricane prone region. A larger initial investment may save you money over the long term through lower utility bills, lower insurance rates, better protection of your home and the life of the roof (more years until a replacement is needed).

The roof system is composed of structural elements, insulation and moisture barriers. A moderately sloped hip roof with simple lines is recommended by the Federal Emergency Management Agency (FEMA) as the best design to resist uplift for our hurricane prone area.

The roof rafters or trusses should be attached to the wall framing by hurricane clips as per code. The roof sheathing is typically tongue and groove plywood or oriented strand board (OSB) nailed to the rafters or trusses.

The best underlayment is a self adhering polymer modified bitumen sheet covering the entire roof deck instead of the standard building paper. The modified bitumen sheet underlayment provides an exceptional moisture barrier throughout construction and later in the event that the final roof covering is compromised. Insurance companies often will reduce your premium with a high performance underlayment.

When choosing your roof, consider the solar reflectance of the material for maximum energy savings. The higher the number (a decimal between 0 and 1) the better. Generally lighter roofs have a higher solar reflectance but there are new advances in paints that create “cool-roofs” in many colors for metals roofs. Look for an “Energy Star” qualified roof product.

The most typical roofing materials in the Lowcountry are asphalt shingle (both fiberglass and organic) and standing seam metal panels. We also see the occasional clay or concrete tile roof.

Asphalt shingles have the lowest initial cost of any roof and the shortest life. Organic reinforced shingles tend to degrade faster in warm climates so it is best to use fiberglass reinforced shingles here.

Tile roofs are very vulnerable to breakage from windborne debris and then become missiles themselves. It is imperative to have a high performance underlayment with a tile roof. Tile roofs also have a greater thermal mass and will radiate captured heat into the structure even when the sun has gone behind a cloud.

Metals roofs include steel, copper, terne and zinc. Zinc and copper have the longest life span. Terne is the traditional metal for on historic home and is fairly high maintenance requiring paint every seven years. Steel with a “cool roof” paint is the most common. High quality metal roofs installed correctly have resisted extremely high winds according to FEMA. Metal roofing is the most ecologically sound choice due to the energy efficiency with cool roof paints, its long life, durable finish, low thermal mass and its one hundred percent recyclability. Metal roofs also have the advantage of easily shedding leaves and pine straw debris.

Your new roof is only as good as the installation. Make sure you use a licensed roofing contractor. You can look up a contractor’s state license at The National Roofing Contractor’s Association has helpful publications

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