What impact does proper underlayment have on roofing systems?

Proper underlayment plays a crucial role in enhancing the overall performance and durability of roofing systems, particularly when it comes to water resistance. The primary function of underlayment is to provide an additional protective layer between the roofing material (such as shingles or tiles) and the roof deck. This layer helps to prevent water infiltration, which can lead to leaks and significant damage over time.

By effectively increasing water tightness, underlayment acts as a barrier against moisture that may enter through the roofing material, especially during heavy rain or snow events. This capability is essential for maintaining the integrity of the roof structure and protecting the interior of the building from water damage.

While proper underlayment might contribute to aesthetic improvements or labor cost management indirectly, these aspects are not its primary purpose. Similarly, flashing remains necessary in certain areas (such as roof joints, vents, and chimneys) to provide added protection against water penetration, and underlayment does not eliminate its need. Therefore, the importance of underlayment primarily lies in its ability to improve water tightness, making it an indispensable component of effective roofing systems.