I have a client who has a home that was insulated with icynene spray foam. The walls have a lot of moisture trapped inside. The foam was sprayed on and then shaved and 6 mil poly installed. Most of the home has moisture trapped in behind the poly. The home is over 100 years old and the mortar in places is not very good. Could this be the reason for the moisture absorbsion. There would be no moisture barrier installed but the water is on the inside of the walls…not the outside edges. They have started to scrape all of the icynene out and are going to replace it. I think poly 2lb insulation is the best route to go…any thoughts.
Yes you are right and they have had nothing but trouble with half pound. Closed cell is the only successful option in this application. No vapor barrier only house wrap.
Is the structure masonry construction with wood frame inside? or is it a veneer?
Hi Ken, we’d like to better understand where the moisture is coming from and why so that we can help you reach a solution that works. We invite you to contact Icynene’s Engineering team on 1-800-758-7325 and we’ll be more than happy to speak to you about the moisture being trapped. Thanks!
The home is double brick but then framed after. The mortar is old and in some places cracked or soft. I have a feeling that the absorption is all coming from the outside over the years. If they go with 2lb poly can they get away without the house wrap and the 6mil.
NEVER GO WITHOUT THE HOUSE WRAP!
In an older home wind is a very big factor in driving rain into a cavity.
If you say it is coming from outside this is where it needs to be stopped not before entering the interior wall.
I can imagine no scenario where house wrap could be applied to a double brick masonry structure such as the one described.
Cameron! It depends on what he is planning? He already says the joints of the mortar are damaged. Is that on the inside or outside? If indeed he does plan to cover it with some kind of siding he will need to protect that area with house wrap first. If he plans to fill the cavity with 2lb Icynene than he will have to correct the problems to the brick on the outside. Since brick can hold a large quantity of water it will not work without having a cavity to wick water away from inside the wall.
Was the house masonry structure? If so, open cell foam should not be used. In any case, the poly “vapor barrier” is not supposed to be used.
Hope this helps;
try a closed cell
The rule is closed cell for masonry and open cell for frame. The open cell foam “breaths”. And a “vapor barrier” on the inside is a big no-no.
For frame buildings or the underside of roof decks, open cell only. There are a lot of “inexperienced” (read: idiot) installers who only use closed cell because of the better R value per inch. I have called out a few, gotten slammed by them and came back to find rotted rafters and the like.
Would be nice if we knew the area of the country you are in. It is a big determining factor in how to insulate.
Hope this helps;
YEP! Agreed
Building science always dictates what to do in your location.
http://www.buildingscience.com/documents/digests/bsd-106-understanding-vapor-barriers