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Understanding Advantages And Disadvantages Of A Synthetic Roofing Underlayment

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If you need a new roof and know a bit about asphalt shingle roofing, then you may understand that shingles are not placed directly on the wooden roof deck. They are instead nailed over a protective membrane called a roofing underlayment. Underlayments have traditionally been made from a felt material. Specifically, an asphalt saturated felt product has been used in the vast majority of asphalt roofing jobs. However, there are some other options. Alternatives may be wise to consider since felt underlayment can fail for a variety of reasons. One such alternative is a synthetic underlayment. Keep reading if you want to learn about some of the advantages and disadvantages of choosing this type of material for your roof installation.

What Are The Advantages Of Synthetic Underlayment?

Synthetic underlayment materials are made from man-made materials like polyethylene and polypropylene. In other words, plastics are typically used to make the underlayment materials. Since synthetic plastics make up the bulk of the underlayment, the material is highly resistant to water damage. Water wicks off the material and rolls away from the roof deck. The material itself is also lighter than felts and other underlayments and it has high tensile strength so rips and tear issues are reduced.

In addition to its ability to remain strong and secure against water damage, the material is resistant to mold and mildew growth since it is synthetic. The material also lies flat when an installation expert adds it to the roof deck and it has a surface that is considered non-skid. This means that there will be a far lower risk of slip and fall injuries during the actual installation process. 

You should know that the synthetic underlayment materials are also resistant to thermal and UV damage. While this is true, the underlayment should not be directly exposed to the sun since it will be covered with shingles. 

What Are The Disadvantages Of The Material?

While the underlayment does have a wide variety of benefits, it does have some drawbacks as well. Since synthetic materials are newer, they may not meet specific building requirements. The roofing materials are also not standardized, so different manufacturers may make the products differently. Not only does this mean that quality and longevity may be different based on the manufacturer, but the underlayment may not be covered under roofing warranties. In other words, if your asphalt roof fails for some reason, your roofing warranty may not be honored due to the placement of the synthetic underlayment. 

Also, while the underlayment is impenetrable, water issues can develop if the seams are not properly secured. Staples are not advised for the synthetic material. Only roofing nails should be used or plastic caps, so make sure that your roofer is using these things if you decide on the synthetic underlayment.