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-   -   Insulating existing exterior walls....... (http://www.diychatroom.com/f103/insulating-existing-exterior-walls-175044/)

DM3 03-20-2013 02:28 PM

Insulating existing exterior walls.......
 
I would like to insulate my exterior walls. Here is the issue, the wall is made up of the following: Brick exterior, 1" air gap, studs (no sheathing) and 1/2" GWB. If I have insulation blown in, masonry absorbs moisture and the insulation will get wet since the insulation will fill the entire gap, thus a mold problem.

I also looked into 'shaving-cream' style foam, but if they add too much it will blow out the gwb, plus it creates a solid mass. If water gets behind the brick, where does it go since the closed cell insulation will not absorb the moisture.

Any suggestions other than ripping all the interior gwb down, insulating and reinstalling the gwb?

Gary in WA 03-22-2013 04:30 PM

Where are you located?

Gary

Nailbags 03-22-2013 04:44 PM

Quote:

Originally Posted by DM3 (Post 1141561)
I would like to insulate my exterior walls. Here is the issue, the wall is made up of the following: Brick exterior, 1" air gap, studs (no sheathing) and 1/2" GWB. If I have insulation blown in, masonry absorbs moisture and the insulation will get wet since the insulation will fill the entire gap, thus a mold problem.

I also looked into 'shaving-cream' style foam, but if they add too much it will blow out the gwb, plus it creates a solid mass. If water gets behind the brick, where does it go since the closed cell insulation will not absorb the moisture.

Any suggestions other than ripping all the interior gwb down, insulating and reinstalling the gwb?

Look in to doing a BIBS that is blown in blanket system. http://www.bibca.org/
That is one option. best of luck
I take it your from the New England states or eastern canada most people don't call sheetrock GWB out side of those area's

HomeSealed 03-22-2013 06:39 PM

+1. Bib system may be a good solution for you.

Gary in WA 03-23-2013 12:50 PM

Nailbags, BIBS would not work in this application without sheathing to stop foam contact with brick veneer. IMO, you could destroy the brick wall. The air space designed behind the brick requires it be left open for liquid water drainage, a capillary break, air pressure moderation and ventilation for drying. http://www.wbdg.org/design/env_wall_masonry.php

There is no easy fix without removing the drywall/insulation. That done, add some strips of I&W sticky wrap to the brick side of the studs (or fanfold) followed with some open-cell or closed-cell rigid foamboard (depends on location for perm rating) cut/cobbled between the studs with canned foam around the perimeter. Use some I&W, first, for the flashing under the f.b. to direct any condensation out over the bottom plate to the brick drainage space. Then your wood framing will be protected from solar drive; http://www.buildingscience.com/docum...n-brick-veneer

OR, you could install a drainage plane material like Delta Wall; http://www.cosella-dorken.com/bvf-ca...LL_Systems.pdf , then BIBS over that.

Gary

Nailbags 03-23-2013 08:49 PM

Quote:

Originally Posted by Gary in WA (Post 1143822)
Nailbags, BIBS would not work in this application without sheathing to stop foam contact with brick veneer. IMO, you could destroy the brick wall. The air space designed behind the brick requires it be left open for liquid water drainage, a capillary break, air pressure moderation and ventilation for drying. http://www.wbdg.org/design/env_wall_masonry.php

There is no easy fix without removing the drywall/insulation. That done, add some strips of I&W sticky wrap to the brick side of the studs (or fanfold) followed with some open-cell or closed-cell rigid foamboard (depends on location for perm rating) cut/cobbled between the studs with canned foam around the perimeter. Use some I&W, first, for the flashing under the f.b. to direct any condensation out over the bottom plate to the brick drainage space. Then your wood framing will be protected from solar drive; http://www.buildingscience.com/docum...n-brick-veneer

OR, you could install a drainage plane material like Delta Wall; http://www.cosella-dorken.com/bvf-ca...LL_Systems.pdf , then BIBS over that.

Gary

Very true slipped my mind. Thanks Gary your all ways there to point out the best way to do it.

Gary in WA 03-24-2013 12:11 AM

Thanks, yes, that was a tough one to make one think.... that's what the "Edit" buttons for...lol.

Gary


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