In northern climates you may find wires along the bottom edges of the roof. These wires are used to heat the show and ice so it melts off the roof without causing an ice dam. An ice dam refers to ice and snow that has frozen at the base of the roof above the gutters. Since the ice is trapped by the gutter, it gradually melts and the water goes underneath the roof shingles. This leads to water penetration problems in the house. Some homeowners don't like the idea of wires in their roof. If this is the case with your client, then flashing can be installed under the bottom few rows of shingles to help prevent water leaks from ice dams. You have to be careful when evaluating roofs. This is another aspect of houses that can really scare a buyer. Often buyers have a good reason to be scared about roof problems, but sometimes they overreact to an aging roof. In either case, you don't want to get any phone calls in the middle of the night from some guy who says his roof is leaking. Especially, if it's within twelve months after your inspection and you never warned him about it. The life expectancy of all roofs depends upon many factors. Some factors are: the quality of the shingles, the quality of the installation of the shingles and the roofing materials, the climate and exposure to the elements, and the maintenance given to the shingles. The vast majority of houses have five types of roofing shingles:  | Asphalt | | Wood Shingles and Wood Shakes | | Slate | | Tile | | Flat Roofing |
Asphalt shingles are classified by their weight. Shingles are rated by their weight per roofing square. A roofing square is a 100 square foot area of the rooftop. Lightweight shingles weigh about 215 pounds per roofing square. Heavyweight shingles weigh about 350 pounds per roofing square. Most asphalt shingles have a fiberglass mat instead of an organic type of mat. Asphalt-Fiberglass shingles have a typical life expectancy of 18 to 22 years. If a heavy weight shingle is used, then the life expectancy can be 30 years. This is because the roofing will stand up to the elements better. Quality roofers give warranties for these shingles as long as 20 to 30 years. As asphalt roofs age, they begin to cup and curl. You'll see these shingles fraying at the edges when they get old. You'll also see pitting of the granules. This is caused by the exterior of the shingle beginning to wear away. These granules are needed to protect the shingle from the sun and weather. | | Check to see how many layers of shingles are currently on the roof. Most local building codes only allow up to two layers of asphalt shingles on a roof. If there are more than two layers, tell the client to find out if this is a building code violation. Three layers of shingles on a roof adds too much weight to the structure. You should only recommend that there be two layers as a maximum. Also, when shingles are placed over an existing layer, they can have a poor cosmetic appearance. The bumpy appearance of the roof is caused by the layer underneath which has cupped and curled from aging. Furthermore, placing roof shingles over an existing layer cuts down the life expectancy of the top layer of shingles. If the house has two layers presently, then tell the client to budget for the next reroofing. They're going to have to strip these layers of shingles off and probably install new sheathing during the next reroofing. This is much more expensive than just having a new layer put over the existing shingles. Especially, if the roof sheathing has to be replaced as well. To determine the number of layers of shingles, look at the visible edges of the roof. If you see two or three shingles, then the roof probably only has one layer. This is because an extra layer of shingles is installed at the edges to keep rainwater from being blown underneath the shingles. Sometimes a roofing contractor will place a strip of aluminum flashing along the edge of the roof shingles. This will prevent rainwater from getting under the shingles but it also prevents you from seeing the number of layers of shingles. To determine the age of the roof shingles you have to use some basic math and your own judgment. This is a good example of where the owner's answers to your preinspection questions come in handy. For instance, the life expectancy of average weight asphalt shingles is about 20 years. Let's say you are inspecting a house that's 30 years old and the roof doesn't show signs of aging. If you see four or more shingles at the exposed edges of the roof, you can assume the top layer is about 8-10 years old. It's just basic math: the first layer lasted about 21 years before a new roof was installed over it. |
