An asphalt shingle roof is the easiest roof for the do-it-yourselfer to maintain and repair.
Asphalt shingles, also known as fiberglass shingles, last for up to 30 years, depending on the slope of the roof and the weight and color of the material, although they can wear out in as few as eight to 12.
The lighter in color the shingles are and steeper the pitch of the roof, the longer your asphalt roofing system will last.
Manufacturers and the building code say shingles may be installed on any roof with a pitch greater than 2/12. (That refers to how high the roof is sloped. A 2/12 roof is considered flat.)
Shingles typically weigh between 180 to 400 pounds per roofing square. A square is a 10-foot by 10-foot area.
Under the shingles, you need a layer or roofing felt, called underlayment. That felt should be 15 or 30 pounds, depending on the slope of the roof.
Local building codes say it’s OK to apply one additional layer of shingles over an existing layer, which means you don’t have to tear off your old roof to lay a new one. If you do this 10 to 12 years after you put on the first layer, you’ll extend the life of the roof and save the cost of tearing off the old material.
A tip: More than two layers of shingles will add too much weight to your home’s trusses. And your roof won’t look nice: It’s easy to spot multiple layers of shingles from the curb because they make the roof take on a “wave” effect.
If you do decide to lay shingles yourself, you’ll need to be meticulous about your measurements. A single, small error can throw off the entire roof pattern! Plus, it could cause your roof to leak.
And don’t forget about ventilation. Rosie recommends continuous ridge venting with adequate soffit vents to increase the life of the asphalt shingles.