Q - We just bought a house and it needs a new roof. What are the various types of roofing materials available? How should I select among them, and will a new roof have any impact on my utility bills? T.F.
A - There are many types of roofing materials available. Several factors to consider when selecting the proper kind of roof for your house are - price, durability and life, effect on utility bills, weight, slope of roof, ease of do-it-yourself installation and fire resistance.Asphalt shingles (organic or fiberglass) are most popular because of their low cost and ease of installation. However, they have the short-est life expectancy, about 20 to 25 years. The recommended minimum roof slope is 2-in-12 for asphalt shingles. For a very low-pitched roof, 1-in-12, either copper, galvanized steel or corrugated asphalt sheet is best.
Metal roofing, aluminum, copper or steel, offers a very long life and is lightweight. This is important since some roof structures can not support the heavy weight of the very durable concrete, slate, or clay tiles. Copper weathers to a beautiful blue-green color, but it's very expensive.
Metal roofing can also reduce the heat gain in your attic in the summer.
This can help to reduce your summertime air-conditioning costs and reduce the thermal stresses on the roofing lumber. In the winter, the type of roofing material does not have much effect on heat loss from the attic.
Slate shingles are one of the longest-lasting roofs (50 to 100 years), but one of most expensive ($500 to $700 per square). A square, the standard measuring unit for roofing, is the amount of material needed to cover 100 square feet of roof. Slate is fireproof, carrying a UL "A" fire rating.
Since slate is dark gray and very heavy, it holds the sun's heat well into the evening. If you air-condition your house in the summer, you may consider stapling reflective foil under the roof rafters. This is also true for clay and concrete tile roofs.
Wood shingles and shakes, made of Western red cedar, are extremely attractive and you can easily install them yourself. The wood shakes are rougher and heavier, so they last almost twice as long as the shingles.
Their only drawback is that they are not as fireproof as the other types of roofs. Check your local building and fire codes before installing them.
You can write to me for UTILITY BILLS UPDATE No. 181 showing a buyer's guide for 12 types of roofing materials showing price, fire ratings, expected life, minimum roof slope, and weight per square, and a list of manufacturers of roofing materials. Write to James Dulley, The Deseret News, 6906 Royal Green Drive, Cincinnati, OH 45244. Please include $1 and a self-addressed business-size envelope.
Q - I am trying to compare my utility bills from last year to this year and I was told to factor it by heating degree days. What exactly are heating degree days? E.W.
A - Heating degree days measure the severity of the outdoor "coldness." The number of heating degree days is determined by subtracting the high and the low temperatures for a day from 65 degrees and then averaging the two numbers. Sixty-five degrees is used as a base because it is assumed that you don't need to operate your furnace when it's 65 degrees outdoors.
Sum the number of heating degree days of one week, one month, or a year. For example, if last January had 10 percent more heating degree days than this January, you should have used 10 percent more energy to heat your home. If you used only 5 percent more, you were more energy efficient.