Guidelines for Roof Work | |
More than 80 percent of the homes in the U.S. have asphalt roof shingles or roll roofing. Another ten percent of roofs are wood, usually cedar, and are either hand-split shakes or shingles. Roofing a house requires a broad array of skills and knowledge, as well as requiring special scaffolding and ladders to reach the work. The work is heavy and involves a considerable risk of injury because of the heights and climbing involved. Many manufacturers of asphalt shingles discourage homeowners from attempting roofing work, because of the consumer liability laws. Still, some shingle manufacturers have moved into the d-i-y market, because there are a number of homeowners who are physically capable of doing the work and who will attempt it in any case. The decision of whether to attempt your own roofing work is entirely an individual one, and should take into account your own experience level, your physical health and strength, and your ability to work at heights. I once knew an airline pilot who was afraid of heights, and would not climb a ladder to change his own storm windows. Obviously, this person was not a candidate for doing his own roofing. If you don't mind climbing, you can at least do periodic cleaning and maintenance on your asphalt or wood shingle roof. A minority of houses, about 10 %, have roofs of metal, slate or tile. Because slate, tile and metal roofs require special installation tools and techniques and professional installation and repair, they are beyond the scope of most d-i-y homeowners. WHEN TO REROOF: Inspect your roof each spring and fall to check for storm damage. If you cannot climb on the roof, use a pair of binoculars to take a close look at the entire roof structure: check rain gutters to be sure they were not loosened by ice at the eaves. Replace or repair any windblown shingles, apply roof mastic around any chimney or vent flashings and valleys, and check in gutters and downspouts for signs of loose shingle granules. As the asphalt shingles dry out, the ceramic granules will come loose and will wash down the roof deck. A buildup of shingle granules, or brittle, broken or curled shingles is a sure sign that the roof is due for replacment. Most older shingle roofs were installed using shingles with a 15-20 year warranty, so if you know the year the roof was installed, you can get a good idea whether the roof may be about due for replacement. ASPHALT SHINGLES: Shingles shed water, but do not waterproof. If properly applied, on a roof with sufficient slope or pitch, the overlapping shingles let the water run harmlessly off the roof, without penetrating into the house. But you should never apply asphalt shingles over a roof that has less than a 2/12 slope, meaning a slope of 2 inches for each 12 inches of lateral run. Do not confuse the roofing terms "slope" and "pitch:" The pitch of a roof is the ratio of the vertical rise to double the horizontal run and is shown as a fraction. For example, a roof that has a 4-in. rise per foot of horizontal run would have a 4/12 slope, but would have a 1/6 pitch (4/24 = 1/6). Should you use asphalt shingles on a roof? A basic rule of thumb is: If you can see the roof from ground level, it is steep enough to have shingles; but if the roof is too flat to be seen from ground level you should install either roll or builtup roofing. To check the slope, place the top end of a 2-ft.-long carpenter's level against the roof and raise the lower end of the level until the bubble is centered in the dial. Then use a rule to measure from the bottom edge of the level's end down to the roof deck. At the lower or outside end of the level, the distance between the bottom edge of the level and the roof should be 4 in. or more (2-in. of slope per foot x 2 ft. of run.) If the roof slope is marginal -- 2 in./ft. (2/12) or less -- use roll roofing or have a pitch and gravel builtup roof installed. For roof slopes of between 2 and 4 in./ft., you can use shingles, being careful to follow the manufacturer's installation instructions for low slope roofs. If your roof slope is 4/12 or more you may apply shingles as per manufacturer's instructions, without fear of leaks due to poor slope or water runoff. SELECTING SHINGLES: Because they cover a large part of the exterior of the house, the color and appearance of the shingles are of primary importance to the consumer. Asphalt shingles are available in a wide variety of colors plus wood tones. The most common type, the 3-tab shingle, may have a warranty of 15 to 35 years, depending on its construction. Increased asphalt shingle life is due chiefly to two factors: they have a fiberglass mat base that is more durable than the old felt shingle base, and ceramic shingle granules have replaced the old gravel granules to help protect the shingles from the sun's destructive ultraviolet rays. It is the sun's heat and ultraviolet rays that destroy asphalt shingles. Shingles are bought and installed on a basis of "cost per square," and weight per square. A square of shingles is enough shingles to cover 100 sq. ft. of roof (there are three bundles of shingles per square, or 33-1/3 sq. ft. to the bundle.) Weight per square is an indication of shingle quality: heavier shingles contain more asphalt per square foot, and so are heavier-duty. A common weight for 3-tab asphalt shingles is 235 lbs. per square (shipping weight.) To find the annual cost of the shingles, divide the total material cost by the number of years of warranty. For example, if enough shingles to cover your roof cost $2500, with a 25-year warranty, the annual cost of the shingles would be $2500/25 = $100 per year. Check warranty information carefully. Most shingle warranties are not transferrable, so if you sell your newly-shingled house, the warranty can not be transferred to the new owner and the warranty lapses with the house sale. Also, look for a warranty that covers both materials and labor costs: some warranties cover the shingle cost only. In this case, if the shingles alone cost $2000 and failed in half the warranty period, ten years for example, you might be looking at a $1000 warranty payment to cover an inflated replacement roof cost of $4,000 for labor and materials. The best bet is to buy shingles with a recognized manufacturer's name on the label, and then narrow your selection on the basis of the warranties offered. Written by Gary Branson. Reprinted with permission. Copyright HouseNet, Inc. |