Two questions about shingle roofing problems

Posted6/28/2020 6:00 AM

Q: The home we are buying has two layers of shingle roofing. The seller assures us that the top layer is only a year old, but our home inspector says the new shingles were installed without a layer of felt. He also found a water stain on the living room ceiling and recommended replacing the entire roof with new shingles. The seller says the stains occurred before the new roofing was installed, but the inspector believes the lack of felt is a serious roof defect. Who should we believe, and what is roofing felt anyway?

A: Roofing felt is a layer of tar paper or other waterproof material that is installed under the shingles to provide a backup membrane in case of leakage. Felt, otherwise known as underlayment, is required when asphalt shingles are installed as a first layer of roofing or when they are applied over wood shingles or built-up roofing.


Some contractors and home inspectors believe felt is required when second or third layers of asphalt shingles are installed, but there is no basis for this opinion in the building code. In those instances, the felt beneath the original shingle layer is deemed adequate.

The ceiling stain, as disclosed by the seller, may have occurred before the new shingles were installed. To allay doubts about the integrity of the new roof, a second opinion from a licensed roofing contractor is advised, but the lack of felt should not be a major issue. Again, felt is not required for a second layer of composition shingles.

Q: Last month, I had to install a new roof on my home in order to close escrow. The old shingles were only 10 years old but were already deteriorated. The buyer's home inspector said this was due to insufficient ventilation of the attic. He suggested installing an electric fan in the attic, with a thermostat to activate the fan during hot weather. Does that sound like a practical solution to you, and are there other possible solutions?

A: Excessive heat build up in an attic can shorten the longevity of composition shingles by causing premature evaporation of the oils in the asphalt. Maintaining lower temperatures in your attic can forestall this drying effect and extend the useful life of the shingles. A mechanical fan can achieve this objective, but there are other options for venting an attic.

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Two effective methods are ridge vents and turbine vents. You've probably seen turbine vents on the roofs of commercial buildings. Rising hot air in an attic causes these vents to spin without the need for electrical motors. However, a potential problem with turbine vents is that they sometimes leak during wind-driven rains.

Ridge vents are probably the most effective means of venting an attic, but installing them may be more costly than adding electric fans in your attic. You can get bids from contractors to determine which method seems most practical.

• To write to Barry Stone, visit him on the web at, or write AMG, 1776 Jami Lee Court, Suite 218, San Luis Obispo, CA 94301.

© 2020, Action Coast Publishing

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