MemBrain: does it do what it claims?
user-1066984
| Posted in General Questions on
I am building my new home with a R 45 wall set up.
R24 blow in and R21 of exterior foam (4 inches)
I have read lots about the risks of interior poly. I found some information from this site leading me to a product called MEM-Brain by certain-teed.
I understand the principle behind the product, what I am questioning is the permability of the drywall that is covering the product with a couple of coats of paint.
Can the wall really dry to the interor with the MEM-Brain and a layer of drywall? Especially after it’s been painted serveral times, say 10 years down the road?
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Replies
Brian,
To read about a study of MemBrain performance, see the article called "Measuring MemBrain Performance" in the June 2006 issue of Energy Design Update.
Here is a link to the issue (look for the article on page 10):
http://www.carb-swa.com/articles/technologies/MemBrain_EDU%20%20June%202006.pdf
In short, MemBrain works.
As long as you don't install an interior polyethylene vapor barrier, a wall assembly can dry to the interior, even through painted gypsum drywall. Adding layers of paint lowers the permeance of the drywall somewhat, but not enough to prevent useful inward drying.
SInce you are dense packing your wall - I would like to recommend the intelligent vapor retarder that is made for this purpose - INTELLO Plus.
It is highly recommended to use a service cavity - so you don't puncture your smart vapor retarder with outlets, screws etc and being able to properly airseal your blow in holes with tape after installation - see more info regarding this in our blogpost about dense packing behind INTELLO
And yes, I do import these Pro Clima products and airsealing tapes with foursevenfive.com