DIY Home Improvement Forum banner

Condensation in Unvented Flat Roof - Rigid Foam Board Installed

5K views 1 reply 2 participants last post by  Bud9051 
#1 · (Edited)
Hello!

I have an addition on my house that was once a patio. They decided to box it in but leave the roof exposed/un-insulated. It is also un-ventilated without any central air and only a fireplace to heat it. I was looking to insulate that room to keep it warmer in the winter so I had a contractor come out and they suggested to insulate it with Rigid Foam Board. Which I had them do. (see attached images)

The problem is that there is now pretty bad condensation in that room. So much that it drips! I assume it's because the warm air inside is meeting the cold plywood of the roof therefore creating condensation. It is spring after all!

What I'd like to know is the following:
  • Is the issue that the roof doesn't have any room to breath?
  • How can I eliminate the condensation?
  • Was the rigid foam board a bad idea?
  • Do I need to take the insulation out?
  • Can I hold the contractors liable for this if it is an improper install?

Any advice is welcome!
 

Attachments

See less See more
3
#2 · (Edited)
"What I'd like to know is the following:
  • Is the issue that the roof doesn't have any room to breath?
  • Ventilation is one option.
  • How can I eliminate the condensation?
  • Eliminate any warm air from reaching a colder surface.
  • Was the rigid foam board a bad idea?
  • There is only one brand of foil faced rigid foam that can be left exposed, Dow Thermax.
  • Do I need to take the insulation out?
  • You can have an unvented roof IF you follow the guidelines. Is that foam tight against the roof sheathing?
  • Can I hold the contractors liable for this if it is an improper install?"
  • Was a permit pulled and was the work inspected?
Bud
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top