Mention roofing to homeowners and their thoughts usually turn to shingles.
Talk roofing with Brian Chambers of Owens Corning and you hear about a trio of elements that go into creating a roof with a long life. Shingles are icing on the cake, but what's underneath is important, too.
Chambers considers a roof to be he sum of its parts: free-flowing ventilation, protective underlayment and good shingles. In other words, a roof is a system of equally critical components.
"Shingles are important, but so are the other two elements if a roof is to do what it's supposed to, and that's protect the home and look good," says Chambers, the company's vice president of residential roofing.
Ventilation is the key to a roof's survival. Moisture and excessive heat milling about in an attic stunt roof life faster than nearly any other factor. Trapped heat and humidity create a breeding ground for mold, contribute to deterioration of a roof substructure and can "cook" shingles from the inside out.
Ridge vents placed at the crown of a roof are a new escape route for heat and humidity, augmenting the familiar square "box" vents typically seen about midway up the roof.
Proper ventilation draws external air up through soffit slits beneath the eaves and out through the vents. Chambers says the goal is to achieve a "balanced air flow" where attic temperatures and moisture content are identical to outside air. It's a mistake to think attic air should be warm and therefore part of the home insulation process. "Good insulation is the thermal barrier that traps heat in living areas, not up in your attic," says Chambers.
Felt sub-layers beneath shingles have been supplemented by saturated asphalt "ice and water shields." This adhesive-backed sheeting provides superior protection, especially when laid in valleys and eaves, against invasive rainwater and ice dams that can cause leaks or lead to rotting of roof timbers. (Ice dams form when heated air escapes through the roof and melts snow. The melted snow refreezes in a series of layers -- all the more reason to keep attic temperatures to a minimum.)
And now for the crowning touch -- the all-important shingles.
Consumers see a plethora of new shingle styles. Premium shingles referred to as "architectural" or laminates have boomed, from 10 percent of the market 10 years ago to more than 50 percent today. These two-ply varieties are replacing three-tab shingles among homeowners who want more color options or the look of slate or shake shingles without the high cost. There's even a super-laminate category of ultra-heavy shingles with limited lifetime warranties. (Warranties of 20-50 years are common on even basic shingles.)
It's little wonder that homeowners want more shingle color and style choices. A roof accounts for as much as one-third of the visible exterior of the house. A good-looking roof has curb appeal, contributing to the house's resale value.
Chambers says the days are gone when homeowners could simply nail on new shingles and climb back down their ladders. He says his company leans toward a network of installation professionals who understand a roof in its entirety.
The big question is knowing when it's time to say goodbye to your old roof. Chambers lists telltale signs of roof deterioration homeowners can readily spot:
* Buckled, cracked, warped or split shingles. This applies to both asphalt and wood shake shingles.
* Excessive granule loss. Some loss is normal but watch for large accumulations in your gutters.
* Blistered shingles.
* In the attic, look for signs of leaks or water spots on plywood or particleboard.
* Attic timbers may show signs of mold, rot or insect decay caused by excessive moisture.
On the Net: Owens Corning: www.owenscorning.com
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