The underlayment is what you see roofers laying down prior to adding the outer elements. Originally it was simply used as a temporary protection against the elements as the more substantial outer layers where being applied. Today underlayment is considered a necessary and required part of the whole roofing process.
The materials used in roofing underlayment fall into one of three main categories – felts, synthetics and barriers. The oldest and most well known of these is the material referred to as paper felt. It is actually a paper material that is saturated with asphalt. This is material comes in rolls, is inexpensive and easy to install with staples or tacks.
It has been used for over 50 years, and is still the main choice for roofers. The risks involved for the future of your roof are that it tears easily during installation, resulting in vulnerability for leaks. Also, it traps moisture underneath. The costs are the reason for its continued use.
Another more advanced roofing underlayment option is the synthetic polypropylene sheeting. These have greatly improved the system by being tear-resistant and wrinkle-free. These materials allow moisture to pass out of the roof system unlike the felts. They are also safer to walk on during installation.
The exact materials used in this product are closely guarded secrets in the manufacturing community. The final category is the water barriers. These are self-adhering sheets that provide the ultimate barrier against ice and water. It is often used under more traditional underlayments to further seal the roof surfaces.
The choice of roofing underlayments depends on several factors. The slope of the roof and the environment in which your home is found are determinants for choosing the correct materials. It is now a requirement for contractors to include underlayment as a necessary part of the roofing process.
It acts a fire resistant agent as well a wind and rain resistor. This is vital second layer of defense for your roof. Now that you know its importance, you should discuss the details of which material to use with your professional contractor.