Selecting Shingle Type

QUESTION: The shingles on our roof are worn and we want to have the roof re-shingled. We don’t know whether to use asphalt or fiberglass shingles. What is your opinion?

ANSWER: Either type of shingle will work for you. Your choice depends on aesthetics, availability and your budget. Generally, the more expensive shingles come with a longer warranty, some of which can reach 20-25 years.

Many people, even roofers, confuse fiberglass and asphalt shingles. Fiberglass shingles are made with asphalt and should be referred to as fiberglass-asphalt shingles.

An asphalt shingle consists of felt base mat made from rags, paper wood pulp. The mat is saturated and coated with asphalt then surfaced with mineral aggregates.

The difference between organic and fiberglass based shingles is more of a concern to the roofer than the homeowner. Fiberglass based shingles were developed because roofers found that asphalt shingles softened during hot weather installations, and were easily damaged. Fiberglass shingles are coated, not saturated, with asphalt and are not easily damaged during hot weather.

Fiberglass shingles have a better fire rating than organic shingles. Nevertheless, the latter is considered acceptable.

Mildew Stain Keeps Appearing on Eave

Q: The 2-foot-wide eave of my house has to be repainted every two or three years because stains that resemble mildew begin to appear. Would this be caused by the kind of wood used in the construction, or do I have a ventilation problem?

A: Your attic probably does not have adequate ventilation. If there are soffit vents, check and see that they have not been covered with insulation. The minimum amount of free air ventilation should be 1/150th of the ceiling area. For example, a 20-by-30 foot house has a 600-square-foot ceiling area. The minimum ventilation (1/150th times 600) is 4 square feet.

For further information on any home problem, write to Popular Mechanics, Readers Service Bureau, 224 W. 57th St., New York, N.Y. 10019.