Everything you Need to Know about Ice & Water Barriers on Shingle Roofs.
The local building codes are very clear. Protection against ice dams is required by most building codes at eaves wherever the January average temperature is 25°F (3.8°C) or lower or where there is a possibility of ice forming in the eaves. (Northeast) Most Saratoga roofing contractors have plenty of experience installing ice and water barrier.
Your roof has many weak points that are more vulnerable to weather conditions than the main field of shingles. Along these penetrations it is good practice to apply an extra layer of protection. Ice and Water barrier is a peel and stick protective underlayment that when applied around penetrations, along the lengths of sidewalls and roof to wall transitions, will protect these weak points and help these troubled roofing areas to last the lifetime of the roof.
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Self-adhering Polymer-modified Bitumen Sheets generally range in thickness from 20 mils up to 60 mils. These sheets will act as a vapor retarder when installed over an entire roof deck.
Ice and water is most commonly known for its use on eaves. . Along the bottom eaves, it is used for protecting against ice and water dams.
Ice dams are caused by the water melting from the top off the roof (where it is heated) and rolling down to eaves where it freezes again. This can continue to happen over and over again depending on the weather. Once this repeatedly happens it will cause the ice to build up farther and farther each time, allowing for the ice to build itself up and through the courses of shingles.
Once the ice gets past the shingles, it then has to make its way past any underlayments before it starts causing damage to the decking and everything underneath it. This melting water is a problem to synthetic underlayment which is just a paper like material that will rip a little when it is stapled and then nailed through during the installation. Any water that makes it past the shingles is prone to leak at any areas that the paper has been ripped.
Better safe than sorry
Ice and Water Barrier however, is made of a more pliable like fiberglass matt. It will “self-seal” around any protrusion, forming tight and adhering to every nail that penetrates the underlayment. This forms a watertight nail hole, and will not let any ice or water penetrate.
When no ice and water barrier is used it will cause the plywood to become wet and prematurely damaged.If this is the case with your home, it will cost more money to have the roof replaced thanks to having to replace the bottom course of plywood as well. It will also cause the bottom course of plywood to become wavy and not last as long as the shingles life expectancy.
Ice and Water barrier is also commonly used around chimneys, under all step flashing at dormers and roof to wall transitions, around pipe flashing and should also be used around skylights. Basically all penetrations through the roof should be covered with an additional layer of ice and water barrier. Ice and Water should be applied at least 2” around all penetrations and should be installed running at least five inches up any sidewalls or chimneys.
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A big leak area we get called out for quite often is the valleys. The most common issue with valleys is that no ice and water barrier was installed. Valleys are more susceptible to leaking because there is usually two roofs worth of water all draining through the same roof area. A lot of Albany roofing contractors will cheap out and not install anything but regular paper in valleys. This will cause water to eventually make its way through the nail holes and damage the houses interior. It is code to install ice and water barrier to every valley and not nail anywhere within six inches of the valley. You also must install the ice and water into the valley before the courses of adjacent underlayments overlap the ice and water at the valley.
There are many different brands of ice and water barrier. Some costing more than others. It is best to match the brand of ice and water to the brand of shingles to be eligible for the manufacturer's warranty. The system will have to be installed by a certified installer in order to qualify for the manufacturers 50 year full coverage warranty.
It is important to know which brand is being used in your roof so that you can compare apples to apples with your roof quotes. The most common brand we use at Infinite Roofing is GAF Weather Watch. This cost a little bit more upfront but qualifies the roof to have the 50 year manufacturers warranty backing up the shingles and labor. Upgrades are available such as GAF’s StormGuard.
Some roofing companies will purposely under bid while failing to mention the brand of ice and water they are using. Then they show up with store brand ice and water which cost thirty dollars a roll as compared to our name brand GAF Weather Watch which comes in at around ninety dollars a roll. Over the course of using six rolls on an average house, this difference in one material alone can be a few hundred dollars less than a higher quality roofing system.
Using a quality name brand of ice and water will offer more piece of mind by including a manufacturers warranty. It will also help reduce the risk of costly repairs due to wall and ceiling staining from leaks.
Grace Ice and Water is the Versace of underlayments and is commonly used on new construction homes. This product costs nearly two times the amount of GAF’s WeatherWatch.
When applied, the adhesion of Grace to the plywood is so great that it will be nearly impossible to remove when it comes time to replace the roof again. When roofing contractors run into homes that installed Grace I&W twenty years ago, they usually have to rip out the bottom course of plywood or scrape the shingles off the I&W the best we can, which still leaves little shingle remnants stuck to the deck and needs to be shingled over.