Quick answer
Can I put a new roof over an old one?
Building code allows one overlay in most NM jurisdictions, but Roof Doctor NM recommends against it. Overlays hide deck rot, void most manufacturer warranties, add weight, and reduce next replacement to 60–70% of normal life. Tear-off is worth the extra $895–$2,500.
“Building code allows one overlay in most NM jurisdictions, but Roof Doctor NM recommends against it. Overlays hide deck rot, void most manufacturer warranties, add weight, and reduce next replacement to 60–70% of normal life. Tear-off is worth the extra $895–$2,500.”
The full detail
If the original roof has any leaks, moisture is already in the deck. An overlay traps it and accelerates rot. Xactimate insurance estimates rarely fund overlays — full tear-off is the standard.
Last reviewed 7/1/2026