View Full Version : Vapor retarders and insualtion at the interior of cold-climate single wythe CMU walls

Michael Thomas
10-26-2009, 10:17 PM
Does anyone have a link to a discussion of best practices / standards for vapor retarders and insulation at the interior of single wythe CMU walls in general, and split face block in particular?


Ross Neag
02-02-2010, 10:11 PM

Did you find anything since this post? I have a few things regarding vapor retarders/barriers but none of them point exactly to our little dilemma in Chicago. By and large they are not a good idea, no matter how one interprets our cold/mixed climate.

Michael Thomas
02-03-2010, 05:26 AM
I've not been able to find any objective studies of this problem, just a lot of (conflicting) opinion.

Fred Weck
02-03-2010, 08:29 AM
The State of Minnesota did a study on the issue, here is a link to it:
Energy conservation - CCLD (http://www.dli.mn.gov/CCLD/EnergyConservation.asp)
Look at the technical opinions.
The state rewrote the energy code after the study was done.

Michael Thomas
02-03-2010, 11:33 AM
I'm not finding single-wyeth CMU walls in that study, just stud walls:


Fred Weck
02-03-2010, 12:20 PM
Sorry, hadn't looked at it in awhile and thought that was the one. (They did another study, but I can't find it anymore)
This link will take you to the Builders Association of Minnesota which has a Field Guide on how to comply with the Minnesota Building Code, the foundation insulation provisions are new, and were done to address moisture being trapped in the interior foundation insulation.
Although still allowed, practically no one is framing stud walls on the interior with fiberglass insulation batts anymore here.