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The appearance of a house roof can certainly enhance the beauty and appeal of any home. While appearance may be important to the homebuyer, the roof must do a whole lot more than just look good.

Consider the average roof has about 1500 to 2000 square feet of surface area. This area is exposed to the full gamut of elements that range from drenching downpours to days on end of misting rain, blistering summer sun and heat buildup, below zero winter temperatures, ice and snow cover, high winds and hail, and other, less obvious effects such as the ultraviolet rays of the sun that attack roofing materials.

Most homeowners take their roof covering for granted. Most roofs perform well for years, even if not periodically maintained, cleaned of debris, or checked for other ailments. It is only when those first spots of moisture appear on the ceiling or a small drip of water comes in during a heavy rain that most homeowners will contact a roofer. Often, by this time, the roof may need to be replaced.

Let’s take a look at the roof as a system. The roof does more than just keep the elements out. On most homes the roof is composed of a frame, usually lumber installed as rafters, or manufactured wood trusses. This frame is then covered with sheathing that ranges from wood planks to plywood or some other manufactured product such as oriented strand board, or OSB. The sheathing gives the frame of the roof rigidity and strength, and provides a surface upon which to lay the roof covering that will keep out the elements.

There are many types of roof coverings. One of the more common and familiar is the three tab asphalt shingle. Probably more roofs are covered with shingles in the Midwest than any other material. The shingles, when properly installed over a solid roof deck, will perform well for 20 years before replacement is needed.

Shingles come is different sizes and shapes, and many are now textured to simulate the appearance of a slate roof. There are many other roof covering materials such as; wood shingles and shakes, terra cotta tile, natural slate, and a host of man made products that range from cement, rubber, and tile to metal.

The selection of the roof covering is usually based on the pitch of the roof, and economics, with the standard three tab shingle being about the most economical choice for the average pitched or sloped roof surface. Regardless of material, it must be installed properly to be effective over the life of the material chosen. The roofer should start with a clean, solid deck. Roof over or layovers can be done, but generally the longest service life (and best appearance) will be achieved when the old roofing materials are removed first. Then the roof deck will be covered with a roofing felt (tarpaper), and flashings will be applied at all roof penetrations and roof to wall junctions, valleys, etc. In cold climates, a special layer of “ice and water shield” will be applied at the eves, to help prevent water penetration due to ice dam formation. Drip edging or flashing should be applied at the gutters and on the rake edge, and finally, the shingles will be applied. Properly installed using the correct fasteners and nailing schedule, the roof covering should last about 20 years. Variables to the service life include quality of the materials used, slope of the roof, and color of the shingles, orientation, and ventilation effectiveness to reduce heat buildup in the attic.

Another common element of most roofs is the roof drainage system. This usually consists of the gutters, downspouts, and leaders used to collect water and drain it off the roof and away form the foundation area. A properly installed, functioning and maintained roof drainage system is essential for the life of the roof and to help ensure that the water coming off the roof does not end up in the basement or crawl space, or damage siding or trim!

Your home inspector has been trained to inspect the roof covering, flashings and any skylights, chimneys, roof penetrations and the roof drainage system. He may estimate the age of the roof covering, and he will report common roofing defects such as improperly applied materials, missing, damaged or improper flashings that could lead to leaks, unusual wear and other problems. He may call for a professional roofer’s evaluation in certain cases where he feels it necessary to do so.

Finally, as a homeowner, you can do your part to ensure a long and trouble free service life. Periodically inspect your roof (spring and late fall). Stand on the ground and use a good pair of binoculars to observe all of the roof surfaces and roof penetrations. Look for loose, bulged, or missing shingles. Check for debris on the roof and clean off any leaves, moss, sticks, or twigs. Clean and maintain the gutters and downspouts. Have a roofer make repairs to any damaged areas, and replace broken or missing shingles. This periodic inspection and maintenance should help ensure a long and trouble free service from your roof!

 This article contributed by: 

David Bunker
Building Inspectors Consortium, Inc.
809 Talbot Avenue
Lake Bluff, IL  60044
(847) 735-1750

Contact David to schedule an inspection!