Repair Leaky Rolled Roofing With New Membrane

By James Dulley

August 22, 2019 4 min read

Dear James: My older house has asphalt roll roofing over an attic/bedroom conversion with a low slope. This old roofing is leaking, and I want to repair it. Is there any way to fix it without replacing it? — Heather V.

Dear Heather: This type of roofing was commonly used on homes like yours due to rolled roofing's low cost and easy installation on roofs with a low slope. This roofing is not as durable as a lapped shingle or metal roof, so it's not surprising that it now has a few leaks.

The easiest and quickest fix, although not the longest-lasting, is a "mop-over" with a liquid sealant. This is a project you can easily do yourself, but you must be careful when working on a roof, even one with a low slope such as yours.

Whenever you are on a roof, it's best to wear a secured mountain climber's harness and gear in case you slip. This will allow you to lower yourself to the ground safely. Also, always have a helper on the ground to call for help if needed.

Don't attempt to install a standard asphalt shingle roof. Even though each shingle is lapped over the lower one, without adequate roof slope, water can flow up under them and leak into your home. This is particularly bad on a west-facing roof, as the prevailing winds can push water up under the shingles.

The best fix for your leaky roof is to install another membrane roof that uses newer, more durable synthetic materials. This typically isn't a do-it-yourself job, so plan on having it professionally installed. When installed professionally, it often has a warranty of up to 20 years. It will cost more than installing another asphalt roll roof, but the newer materials require little maintenance.

These membrane roofs are most often used on commercial buildings, so you may have trouble finding a roofer to do the job. If you cannot find a local roofer, contact the following membrane material manufacturers: Carlisle SynTec, 800-479-6832; and Firestone Building Products, 800-428-4442. They may be able to give you names of local installers.

Synthetic membrane roofing provides advantages over lower-priced asphalt rolled roofing. Seams between the synthetic membrane pieces can be sealed better than with asphalt rolled roofing. As the area to be covered on your roof is fairly small, one piece may be large enough, and the installer may not need to seam two pieces together. This reduces the chance of leaks.

Various types of synthetic membrane materials can be used, and they are referred to by acronyms such as EPDM, CSPE, CPA, CPE and EIP. They fall into three general classes of materials: thermoset, thermoplastic and modified bitumen.

Any of the above materials would work well for your roofing needs. They all are bonded or attached with mechanical fasteners to the solid roof sheathing. Thermoset membrane materials are often the overall best to use because they are chemically cross-linked and they are not affected by heat or by most chemicals in the air and rain.

Another roofing option, although expensive, is a metal roof. Metal roofs are very attractive and durable, many having a lifetime warranty. You have many metal options, and because metal roofs do not use a lapped shingle design, leakage during storms should not be a problem.

Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com. To find out more about James Dulley and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

Photo credit: sandid at Pixabay

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