Helpful? 0

Interior retrofit with MemBrain

I am retrofitting a 1920's era, balloon framed, south-half, east west semi in Toronto and am hoping somebody can weigh in on my approach. All my work is from the interior.

On the outside of the stud cavity there is plank sheathing ~1/2" x 8" with gaps and kraft paper. The west face is brick clad, and the south and east have aluminum siding with a minimal foam backing and shingles behind. I suspect, but am not certain, there is also brick behind that. I know builders can skimp on side and rear, but the same style neighboring houses are brick on all sides.

My plan is to install R14 Roxul in the cavity followed by MemBrain 'Smart' vapour retarder and latex painted GWB. The thought is that this will resist changing seasonal temperatures and vapour drives, and during the summer allow the wall to breath and dry to the interior. Based on Martin's response about Latex paint perms in an early 2010 post, it seems like the paint and MemBrain will change fairly in tandem and therefor might be redundant.

My concern is that the brick will act as a reservoir and the asphalt and siding are not particularly breathable and I risk trapping moisture during times when the MemBrain is tightest. I will also have a gap in this system in the bathroom which we've decided not to touch currently and in the kitchen where it is currently insulated but without barrier. Those would be fixed in the next few years.

I am going to do the work myself, and am not interested in the spray foam.

Any thoughts are much appreciated.

Asked by drew adams
Posted Fri, 07/11/2014 - 11:24
Edited Fri, 07/11/2014 - 16:20

Tags:

2 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Drew,
I don't think the assembly you describe will trap any moisture. It won't be particularly well insulated, and it may be leaky, but it won't be risky.

Answered by Martin Holladay, GBA Advisor
Posted Fri, 07/11/2014 - 14:26

2.
Helpful? 0

Drew,
By the way, you almost lost me in your first sentence, when you told us that your house is a "south-half, east west semi."

Is that anything like a north quarter southwest hemi?

Answered by Martin Holladay, GBA Advisor
Posted Fri, 07/11/2014 - 16:23

Other Questions in General questions

A very low addition...

In Energy efficiency and durability | Asked by ron letourneau | Oct 29, 14

Closed crawlspace with dehumidifier and foundation insulation

In Energy efficiency and durability | Asked by Michael Geoghegan | Oct 27, 14

Radon mitigation or ERV for old home with dirt wall basement

In General questions | Asked by Scott Van Der Veer | Oct 30, 14

Drywall directly on stem wall

In General questions | Asked by Tom Frisch | Oct 30, 14

Foam Insulation Question For 100 Year Old Brick Home

In Green building techniques | Asked by Wes Leland | Oct 30, 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!