What type of felt underlayment should you use for metal tiles?

What type of felt underlayment should you use for metal tiles?

• A. 30 pound or two plies of 15 pounds
• B. 15 pound
• C. 60 pound
• D. None required

Answer: (A)

Metal tiles need a durable, puncture-resistant base that also provides a secondary moisture barrier. The recommended approach is to use either a single layer of 30-pound asphalt-saturated felt or two plies of 15-pound felt. This thickness gives enough strength to resist nail punctures and tearing from installation, while still being practical to install and compatible with most metal tile systems. Using just a single 15-pound layer is typically too thin to withstand fastener nailing and the movement of metal tile installations, which can lead to leaks. A 60-pound felt isn’t the standard practice for metal tiles and isn’t usually specified by manufacturers for this application. And none required would ignore the need for a protective underlayment unless a specific factory-installed system is provided.

Metal tiles need a durable, puncture-resistant base that also provides a secondary moisture barrier. The recommended approach is to use either a single layer of 30-pound asphalt-saturated felt or two plies of 15-pound felt. This thickness gives enough strength to resist nail punctures and tearing from installation, while still being practical to install and compatible with most metal tile systems.

Using just a single 15-pound layer is typically too thin to withstand fastener nailing and the movement of metal tile installations, which can lead to leaks. A 60-pound felt isn’t the standard practice for metal tiles and isn’t usually specified by manufacturers for this application. And none required would ignore the need for a protective underlayment unless a specific factory-installed system is provided.