Sloped Roofs - Most roofs are sloped, and many are covered with asphalt-composition shingles. In fact, this type of material is the most common roofing material, and is used on more than eighty percent of roofs that have a moderate slope to steep slope. When the shingles are nailed in place, they resemble and function like the scales of a fish. Asphalt shingles effectively shed water down the roof.

A roof could also have wood shakes, tile, metal or slate. The fact remains that none of these outer materials actually protects the house and sheds the water. Instead, it is the material under the shingles, or underlayment that keeps out the water. The real function of the wood, tile, metal or slate is to provide a pleasing appearance and to protect the underlayment from nature.

Wood shingles also are used on roofs with a slope. Both cedar shakes and wood shingles are popular in a variety of climates, and both can add architectural appeal to homes. If installed professionally, the homeowner can expect a reasonably long service life.

Both wood shingles and shakes are sawn on the bottom or underside. However, a shake is split on the top face. In contrast, a wood shingle is sawn on the topside. This slight difference in manufacturing means that a shake has a much rougher, rustic look. In contrast, the wood shingle looks much more uniform. The difference in appearance is quite noticeable.

When roofing a home, climate often dictates that the ?best material? be used over the ?most appealing? material. In warmer climates, where the roof stays hot for long periods of time, concrete or clay tiles often are used. On the East Coast, slate roofs have been popular because of their stability in harsh winter conditions.

Both clay tiles and concrete roofs are durable, often lasting many decades. Both materials are likely to outlast asphalt shingles. However, installation is more complex and costly. Also, both materials can be more expensive to repair.

Over the years, a number of composite shingle types have come and gone in the sloped roof market. Far less durable and more expensive to repair, many of them ended up on the losing side of class action suits.

Flat of Low Sloped Roofs

Covering for flat or low-sloped roofs fall into a completely different category. Without slope, they cannot rely on a ?fish scale? configuration to shed water. Dead-flat roofs often experience water ponding (accumulating) on parts of the roof.

One problem with standing water on the roof is that it is heavy. Water weights 62.5 pounds per cubic foot, in. a one-inch pond converts into 5 lbs per square foot. This adds an unnecessary load to the homes structure. The added weight could have serious results if not controlled. Another problem is that water can find its way through any small hole or crack in the roof and damage the home below.

No roof is purposely built completely flat anymore. Now, all roofs must have at least some slope. To fix this problem in older homes, tapered foam board insulation can be used to create a slight slope toward drainage points (roof drains or scuppers).

Existing dead-flat roofs require a watertight membrane running edge to edge in order to work effectively. For years, the popular covering was nicknamed ?tar and gravel?. The technical term for this type of covering is a ?built up roof?. This is because the covering is built up from layers of roofing felt, each being sealed with hot tar. Several layers of tar and felt are laid down and covered with a final ?flood coat? of hot tar. Small diameter pea-sized gravel then is embedded to protect the underlying layers of felt from sun and weather damage. When finished, the waterproof membrane should protect a home for years to come.

As technology advances, so do low-slope roofing options. Today's neoprene, rubber, and other synthetics are proven materials for use as water-tight membranes. Not only do they last longer, but they are also easier to install because they come in wider rolls. These wider sheets require fewer joints, making leaks less likely. Depending on the particular system, a single ply membrane can be covered with gravel to protect it from the sun. Insulation can be installed either under it or on top of it.

Another material used on flat roofs is urethane foam. Sprayed on the roof decking, the urethane quickly expands to form a layer of closed cell foam. The foam is great at insulating roof decks from heat. However, the foam itself does not fare well in the sun's rays and requires its own sprayed-on coat of protective material. The foam can help provide a needed slope to a flat roof, but it can be easily punctured. If your roof has urethane foam, we recommend regular and conscientious maintenance.

Extending the Life of Your Roof

These tips will help you extend the life of your roof covering.

1.Keep surrounding trees trimmed so they do not touch the roof. Branches that are heavy with snow or hit the house during high winds can damage a roof.

2.Look for missing, out of place, cracked, or curled roof components. This is hard to do without going onto the roof, so we recommend leaving the roof walking to professional, such as your Barrie Home Inspector, or roofing contractor

3.Make a habit of cleaning the roofs surface, gutters, and downspouts twice a year. Also make an inspection after any violent storm.

Roof Flashings

The most common places for a roof to leak are where the roof covering meets other surface or materials. Chimneys, plumbing vents, roof vents, and sidewalls should all be protected with seals called ?flashings?. Flashings should also be used on adjoining sidewalls and dormers, as well as where two adjacent roof slopes meet in a valley. These are all potential leak areas. Therefore, the proper installation of flashings is critically important.

After the flashings are installed, they should be require little or no maintenance, and they should last the life of the roof covering. It is important to note that roofing cement is NOT a flashing material. If flashings or patches on your roof have been sealed with roofing cement, you should inspect these areas often and renew the seal frequently. When you check your roof, make sure to look for damaged or worn flashings. These should be replaced quickly.

The ?Barrie Home Inspector? provides this article as a guide for homeowners. Please use a contractor or professional home inspector when you suspect problems with your roof. Napoleon Home Inspections does not recommend that the homeowner walk his own roof unless proper ladders and safety lines are in place and attached to appropriate equipment. Remember your safety is of paramount importance.