Q&A / 

Membrane Roofing – Avoid Windy Rain and Ice Dam Leaks

The past two winters and summers have made me a believer in water and ice roof membrane products. The people in our coastal areas have been pounded with hurricanes which are accompanied by vast amounts of wind driven rain. Homeowners in the snow belt of the USA were buried with record snowfalls in the winter of 1995-96. These snows create ice dams. The ice dams in turn create rivers of water in houses. Fortunately there is a group of products which can minimize or eliminate entirely leaks caused by these problems.

What are the Membranes?

The membranes which eliminate the roof leaks are simply sheets of modified asphalt. Standard asphalt is mixed with rubber and other proprietary compounds to make it sticky and flexible. This mixture is then applied to a plastic sheet. The plastic sheet allows you to work on top of the product. Without it, you would get stuck on the roof like a fly on fly paper! The membranes are usually about 3 feet wide and come in rolls that contain about 60 to 70 linear feet.

Where Do They Go?

The membranes are installed on areas of a roof that typically can be trouble spots for leaks. Leaks from wind blown rain or ice dams can develop at the lower edge of a roof near the gutters, along the side edges of a roof (rake edge), in valleys where two different roofs intersect, at skylights, other flashing areas (chimneys, plumbing vents, etc.), and at roof slope changes.

The membranes are applied directly to the wood roof deck surface before any felt paper or shingles are applied. That is one reason why they are so sticky. They stick tenaciously to dry, dust free, solid wood.

How Do They Work?

You might ask why one can't simply use heavy 30# felt paper in these same areas to prevent leaks. That would be a fair question. The reason is simple. The nails used to tack shingles penetrate the felt paper. The felt paper does not completely seal around the shaft of the nail. This is where the water starts its journey into your home.

The membranes are different. The thick layer of rubberized asphalt readily coats and seals the shaft of any nails that penetrate the membrane. This is why they stop water. The water which gets under the shingles simply flows over the top of the membrane until it gets to the bottom edge of the roof. There it exits without doing any interior damage.

Are They Worth the Expense?

If you have ever experienced a persistent leak from an ice dam or a leak from wind blown rain, you already know the answer to this question. Ice dam leaks are sinister. Once they start, there is no safe way to stop the leak. It is cold, slick, and dangerous on the roof. I know of a roofer who broke his back trying to break up an ice dam. I can tell you that I would never go up on a roof to beat the ice. Not only is it dangerous, you can cause severe damage to the shingles.

Gale force winds, thunderstorms, and hurricanes can make life interesting while up on a roof as well. I have been there. It is frightening and idiotic to try to stop a leak during a violent storm. 

Oh yes, insurance companies will take care of all your problems you say. You can't be serious! Why go through all of the hassle and problems in doing repair work? You talk about nightmares......!

If you are re-roofing or installing a new roof, give the membranes strong consideration. It is very tough to install them at a later date.

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