What is the primary purpose of underlayment in roofing?

The primary purpose of underlayment in roofing is to protect from moisture infiltration. Underlayment is a critical component installed beneath the roof covering, acting as a barrier that prevents water from entering the roof structure. This is especially important in areas where roofs are more susceptible to leaks, such as valleys, around chimneys, or in regions that experience heavy rainfall or snow.

The material used for underlayment, such as synthetic sheets or felt, is designed to withstand exposure to water and maintain its integrity over time. By providing this moisture barrier, underlayment helps to protect the underlying materials of the roof and the home’s interior from potential water damage, which can lead to costly repairs and structural issues if not addressed.

While some roofing materials might offer a degree of insulation or aesthetic qualities, these are not the primary functions of underlayment. It is fundamentally about safeguarding the roof and its supporting structures from moisture-related problems.