What is the purpose of an underlayment in roofing?

The purpose of an underlayment in roofing is primarily to provide a moisture barrier. This layer is crucial as it helps to prevent water intrusion under the roofing material, protecting the underlying structure from potential damage due to leaks, condensation, or ice dams. By creating this barrier, the underlayment enhances the overall performance and lifespan of the roof.

While insulation, fire resistance, and support for the roof structure are important considerations in roofing systems, they are not the primary functions of underlayment. Insulation is typically addressed through other materials and techniques that focus on thermal control. Fire resistance is often managed through the selection of roofing materials themselves rather than the underlayment. Similarly, the structural support is mainly provided by the roofing framework and not by the underlayment layer. Thus, the correct focus on the underlayment’s role emphasizes its function in moisture management.