When constructing a new roof, you and your contractor have several decisions to make, including what type of underlayment to use. The underlayment is beneath the shingles and helps to protect against leaks. Before making your decision, you need to know the pros and cons of each option you have. 

Felt Underlayment

Felt underlayment is used by many homeowners because it is considered to be the most affordable option. The underlayment consists of paper that has been combined with another material, such as asphalt or fiberglass. If you live in a climate that does not experience a great deal of rain or snow, this is a solid choice. You can improve its performance by having it installed in thicker layers. 

There are some drawbacks to using a felt underlayment. For instance, it is extremely heavy. Before laying it down, you need to ensure that your home is structurally able to handle the weight of the underlayment combined with the shingles and other components of the roofing. A felt underlayment also requires that the shingles are installed within a few hours of placement. If left exposed too long, it can be damaged and need to be replaced. 

Synthetic Underlayment

Synthetic underlayment consists of materials like fiberglass and polyester. As a result, it is far more lightweight than felt underlayment. It is also easier to install than the felt. The contractor can place the underlayment and complete the installation of the shingles the next day, if needed. Synthetic underlayment is considered to be extremely durable and a safer option for installing. It is not as slippery as felt can be sometimes. If you live in a particularly wet climate, synthetic could be your best option because it has a better moisture barrier than felt. 

Although there are many advantages to using a synthetic underlayment, there are some drawbacks. For instance, it is pricier than felt underlayment. However, because it is more durable, you get more wear out of it than the felt. Synthetic underlayment is available as a peel-and-stick option and in a roll. If you opt for the peel-and-stick, it can take more time to install it than the roll option and felt underlayment. 

Whether you choose to go with the synthetic or felt underlayment is your decision, but it is worth assessing your choices with your roofer. He or she can make a recommendation based on experience and the condition of your roof.