Return to Installation
Return to Forum
As I educate myself on roofing, it occurs to me that the integrity of the roofing only lasts as long as the underlayment. The metal roofing may last 50 years but the underlayment will fail long before that, especially the lighter weight felt, requiring a re-roof. Would matching the expected life of the roof with the expected life of the underlayment be optimal? Can you remove and reuse metal roofing with replacement underlayment?
Metal roofs are very different from slate and tile which depend almost exclusively on underlayment for watertightness. Underlayment provides protection during the installation process (which can be lengthy), and separates existing asphalt shingles (if left in place) from the back of the metal. Underlayment is also required by code and provides protection if a flashing fails during a particularly heavy rain or something. Very few if any metal roofs, though, depend on underlayment for watertightness. Roofs should never be installed at lower than their minimum required pitch. Also, just as further information, much of the industry has switched to polymer-based synthetic underlayments that, once encapsulated on a roof system, have virtually unlimited life.
+1 to Todd's comments.
Underlayment, in the case of metal roofing, is more specifically used as a slip layer to provide a level of abrasion protection to the back side of the metal panel.
On some level, there might be some protection against condensation on the backside of the panel, but that is about it.
Thank you Todd and Eric.
This information will factor into our home design and build in Idaho.
If you would like to reply to this thread, please
If you do not have an Ask the Experts forum user account,