An important element to maximizing roof performance, longevity and building protection on low slope roof systems is the understanding of underlayments and vapor retarders.
Purpose of underlayments:
- Water barrier (secondary)
- Thermal insulation barrier
- Vapor retarder or barrier
- Air barrier
Types of underlayments:
- Felt underlayment
- Synthetic sheet underlayment
- Self-adhering membrane underlayment
Importance of vapor barriers with metal roofing:
- Vapor barriers inhibit the passage of warm, moist air into the inner areas of the roof system
