Meyer's House Hints

by Bob Meyer

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Roofs

In past columns we’ve talked briefly about roofs, first as part of our spring checklist and then concerning roof drains. This time let’s take a look at roof forms, functions and materials.

Functions

Probably in the simplest, most basic terms, a roof does two things: it keeps “bad” things out “good” things in!

Roofs in our area generally use a combination of slope and impervious coverings (such as shingles) to keep “bad” things such as rain, snow and wind out of our homes.

Similarly, through a combination of covering and insulation, roofs keep good things such as conditioned air (heated or cooled) inside.

Finally, a roof many times also provides the function of tying various other elements of a building together. From a structural standpoint, a roof must not only be able to support its own weight, but also must be able to support the weight of snow upon it as well as the force of wind blowing against it.

Roof coverings

The “perfect” roof covering material would be inexpensive to purchase, quick and easy to apply, light in weight, pleasing in appearance, resistant to damage and never need to be replaced.

Unfortunately, the “perfect” roofing material doesn’t exist. While there are a wide variety of roof covering materials in use throughout the world, in our area, several materials are most commonly used. (And some of these actually satisfy quite a few of the above requirements for perfection!)

Roofing shingles are manufactured from asphaltic materials covered with granular minerals or aggregate. The aggregate is embedded into the shingle surface during manufacturing to provide color as well as to strengthen, bind and protect the surface of the shingle from both erosion due to water runoff as well as other deteriorating effects of the elements, such as aging due to sunlight. These shingles are usually manufactured with high-strength, low-weight reinforcing materials such as fiberglass for additional strength.

Most modern roofing shingles overlap in such a way as to provide a double thickness on the roof. They are also self-sealing. Due to spots of asphaltic materials placed on their surfaces during manufacture, once they are place on the roof, the heat of the sun softens the spots, in turn sealing upper and lower layers together.

Roofing shingles can only be used on sloped roofs. (They are unsuitable for flat or very shallow pitches.)

Metal, fiberglass and similar roofing materials are most generally used for utility-type construction rather than residential construction in our area. Some of these materials come in a variety of colors and are usually corrugated or folded to provide additional strength. The chief complaint with this type of roofing is that it is noisy—during rain and especially during hailstorms!

There are, of course, many other types of roofing materials available, including plastic membranes, built-up roofs (alternating layers of bituminous-impregnated paper and bituminous materials, topped with aggregate), terra cotta, slate, copper, wood shakes, etc.

Although many of these materials make excellent, durable roofs, they are not widely used in our area for individual homes due to weight, expense, specialized installation requirements and other factors.

Next week we’ll take a look at some common roofing problems.