Guest User
6/29/2015
I have question regarding vapor barriers when installing a metal roof over existing shingles. There seems to be some debate on whether the layer of existing shingles will act as a vapor barrier. We currently have a project home that has a metal roof installed over an existing layer of shingles. This metal roof has been in place for approximately 6-8 years and we do not see any signs of issues with the decking in the attic. Seems like there are no issues, but want to make sure we aren’t overlooking something.
Todd Miller
Classic Products, Inc.
6/29/2015
There should, in my opinion, be a layer of underlayment between the old shingles and the metal roof. Do you have anything or is the metal direct on top of the old shingles. The place for a true vapor barrier is below the ceilings, not in the roof assembly.
Guest User
7/28/2015
"The place for a true vapor barrier is below the ceilings, not in the roof assembly." - below the ceilings - DOES THIS MEAN IN THE LIVING AREA?
Info @windowsonwashington.net
An informed customer is our best customer.
7/28/2015
No. It means that if you are going to have a vapor barrier, it needs to be towards the warm wall.
Guest User
7/29/2015
Thank you, Mr. Novotny.. That's what I thought Mr. Miller meant, although that is not what he wrote. i.e. On top of the ceiling, on the bottom of the ceiling joists, on the top floor.
Info @windowsonwashington.net
An informed customer is our best customer.
7/29/2015
Once you start talking about ceilings vs. attic vs. roof...its easy to get things twisted around. Warm side placement is where it goes, if you even require one. It should be on the backside of the conditioned space drywall.
Todd Miller
Classic Products, Inc.
7/29/2015
Sorry for my confusion -- I do see where my fingers got ahead of my brain above!

If you would like to reply to this thread, please log in. If you do not have an Ask the Experts forum user account, create one here.

Find a Contractor

Get Started Today

Take the first step to increasing the value of your home with a great looking, durable, fire resistant and energy efficient metal roof. Browse our list of qualified MRA Member Roofing Contractors in your area for a free consultation and estimate.