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IBJammin 02-04-2008 03:05 PM

Mold Vapor Barrier Question for the Experts.
I recently found mold behind the wainscoting in my dining room on the sheetrock below a bay window. I thought the mold might be coming from condensation from the window. After further searching, I found that behind the sheetrock and the insulation, that the foamboard on the outside of the studs just below the window had wide gaps just on the 45 degree corners of the window. Then I found out that the mortar joints on the brick where these gaps were needed repairing because moisture was getting in through the mortar joints, through the gaps in the foamboard causing my problem. I used that foam expanding product called Great Stuff to fill the gaps in the foamboard because it says it is water proof. I am going to repair the mortar joints to fix that problem. I was wondering once I install the new insulation, would it be a good idea to maybe put up some poly film as extra protection. I also plan to use that mold and moisture resistant drywall (DensArmour sp?) this time. Please help.

inspectorD 02-04-2008 06:11 PM

Hi IBjammin
So you want the good news or the ....nevermind...I'll just give you the bad news.
The siding is brick, with gaps in the joints that are letting in moisture..with a foam backing board at the interior of this space.

Basically what you have is a couple of issues.
1. The window area was poorly sealed around the exterior and let water in.
2. you found holes in the mortar joints and sealed them with foam. Those holes are for air movement to dry the backside of brick when it gets wet. Brick can absorb about a pint of water, and is porous material. When you seal the holes you stop the convection of air from the bottom holes to the soffit roof line.There should be a 1 inch air space from the brick to the board...all the way up and sideways. And there needs to be a continuos moisture barrier on the it doesn't get wet.
The board behind the brick is not for brick siding applications.

Sorry to be the guy, but you really should have a good reputable mason come buy and give you a look, then tell us and we can help.

Some pictures would help too.:D

I'm sure the guy's will be by to put in 2 more cents...or keep the meter runnin.

patterrw 02-13-2008 08:37 AM

IBJammin & Inspector D:

After doing some searching...I found a post to add my similar problem....not quite as bad as IBJ, at least that I have found yet...

My Scenario:

1964 Brick veneer home in coastal SC, originally had a 1 car attached garage...which was converted into a living room & washroom in 1970-ish, by sheetrocking all walls in living room and adding large (4'x4') single pane window where garage door was, and matching the rest of the brick for where the garage door was.

Floor was raised in living room off of slab by 2x6 and subfloor, then carpet (have not pulled up subfloor yet to check for vapor barrier...floor in washroom is still on slab..

ISSUE: We are in the process of converting the washroom (4'6"x12') into a 1/2 bath and mudroom/washroom...I have begun pulling the old 1/4" plywood off of the exterior walls, to discover that there is no insulation in these walls (and I expect no insulation in the living room walls either). Construction seems to be, from outside in;

Brick and Morter
15 lb felt paper, overlaped top piece over bottom
2x4 wall studs
1/4" plywood
1/2" drywall (in living room only)


How do I unsulate these walls and still maintain the airspace needed for the bick/walls to breathe to avoid IBJammin's problem in the future...

the only advice/solution i have recieved thus far is

1. cut 1" rigid foamboard to fit in between exterior studs (R-4/5)
2. attach sheets of rigid foamboard on over walls/studs (R-4/5)
3. cover foamboard with drywall/finish wall (R-?)

inspectorD 02-13-2008 11:48 AM

Is that even a word??:rolleyes:
As Yogi bera used to say....The issues you two are talking about are similar but different...:confused:
The insulation you do not have in your walls, is the reason they are still there. The walls have a chance to dry out.
I would ask this question to an expert who can see your situation. Here is a place where we would all like to help, however EVERY scenario is different. There are just way to many different things which all need to be evaluated to understand what will happen when you add a new insulation to your project, if you want it to last a long time.
I know others may not agree and just tell you to put the rigid foam in, but you asked me for my opinion.

Water collects in strange places sometimes, when it hits it's dew-point it will condensate. Where that is in your wall only someone local can answer that. Contact a home inspector, or a really good reputable contractor in your area for some solid advice. Try for some educational links.
Good luck.:)

patterrw 02-14-2008 07:55 AM

Whatever I do...the interior sheathing that was up on the wall will have to go back up, as I am pretty sure it was providing some rigid support to the 2x4 wall construction...since there is no seathing on the outside or any cross bracing to speak of :(

jack3140 02-17-2008 05:16 PM

if i may i think your condensation problem comes from the fact that cold air is hitting the wall from the outside causing the moisture inside to condense on the wall . before you reinstall the sheating put in some insulation and a vapour barrier and make sure the vapor barrier is on the warm side in winter hope this helps good luck

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