Foam Board for intex

After 4 years of a 16x48 intex ultra frame, the swg and the metal poles have decided its best if they see other people. That being said we are purchasing a replacement later today and are considering placing foam insulation sheets underneath. My question is how many 4x8 boards would we need for a new 16x48? Any help is greatly appreciated.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.