Fundamentals of Roofing

by Jennifer Weldon

The roof is one of the most important features of your home. It provides the topmost layer of protection between your home and the elements. Understanding the fundamentals of your roof’s construction can be vital to spotting any problem areas in the future.

Roofing Sheathing & Trusses

The truss system of your home is what supports the roof. For many homes roof trusses are manufactured off site, brought in by truck, and hoisted up by a crane. They are then nailed into place. These roof trusses resemble large triangles. For a custom built home, the roof trusses are made onsite and can be varied in appearance. They are built depending on the roofline, and may consist of beams and rafters that are structurally engineered to support the roof. The pitch, or slope of a roof, ensures that water or snow will not collect on the roof and cause it to cave in. After the truss system is in place, sheathing will be laid. Typically OSB (compressed particle board) or plywood is used as roof sheathing, depending on your builder and budget. This is the foundation of your roof.

Building Paper

Paper is then laid atop the OSB or plywood. Building paper is typically thin and black. Proper installation will ensure there are no gaps or holes for water to penetrate and seep into the lumber below.

Roofing Shingles

Once the building paper is laid, shingles can be installed. There are a variety of shingle materials including asphalt, wood, metal and clay tiles. The installation process of each may vary. A basic component of all roofing shingles is that they overlap to prevent water intrusion. Shingles are typically laid starting at the bottom of the roof by the eave. Roofers will then work upwards to create this overlapping effect. Rain and snow flows towards the ground, so this is another way that roofs resist water.

Roofing Problems

You can expect to have roofing problems at some point over the life of a home. Different shingles have different life spans. Traditional asphalt shingles typically last 10-15 years, while architectural shingles may last 25 years. Replacing any shingles as soon as they need repair is vital to maintaining the integrity of your roof. Shingles prevent problems to the paper and OSB or plywood below. Problems at that level are more costly and involved. If you notice waves in your roof, the lumber underneath may be warped due to water damage. While logic may tell you to simply patch any shingle repairs by laying another row of shingles atop the old, this will only buy you limited time. Any shingle deficiency can compromise the entire roofing system. It is best to have a professional roofing contractor replace the shingles so they can achieve the layered, waterproofing effect.

Roof Leaks

If you notice any leaking in your roof, try to evaluate the problem from the outside and the inside in the attic. It is possible hail damage, or a limb due to high winds has breached your roof. Any hole in your roof can cause major problems. Sometimes a large dent in your roof can lead to a roof leak when water collects and seeps through all the layers. Sometimes you may notice such damage before any major leaking occurs. Seek to have this area repaired immediately by a professional roofing contractor. By being fastidious in the maintenance of your roof, you may prevent having to replace the entire roof.