We have brick veneer on the SW side of our 9 year-old house.  All of the exterior walls in one of the rooms on the SW side with brick veneer has water damage.  The bottom 1/3 of drywall was wet.  The drywall was removed and very wet cellulose insulation was found (only the bottom 5 feet was wet).  The insulation was completely removed and there is black mold growing on the 2x4’s and the OSB all the way to the ceiling.  We had the roof inspected and it was ok.  We then inspected the brick veneer and found no weep holes, no flashing and numerous large holes where mortar should be.  We suspected brick vaporization as a cause of our problem.  The outer surface of the OSB was wrapped in Tyvek according to the builder.  The statute of limitations in Kansas is now only 5 years for building problems.  Our builder thinks the problem is too much humidity in our house, particularly this one room. 

          We recently checked the humidity in the whole house, and it was 42-49% this summer shortly after the problem was found.  We had all of the other exterior SW facing walls checked by a mold expert who said, after taking off a small portion of drywall, that there is mold behind these walls as well.  Our questions are:  1) Is the problem caused by our brick veneer wall or do you think the builder is correct?  2) If it is a brick veneer problem, should we replace the brick and have someone else do it correctly, or do you think we need to put up concrete siding or some other siding.-M  & S , Kansas

            Your builder is of course wrong.  Relative humidity in your part of the country is unlikely to cause a problem such as you describe.  Your builder’s response is quite normal, that is “I am not responsible.”

            It is very common for brick veneer to be improperly installed with water intrusion and subsequent mold infestation.  The absence of weep holes, absence of flashing, and the presence of numerous “large holes” in the mortar are indicators of poor brick veneer installation and in your case increase the severity of the problem.  If you were to remove some of the brick, you would likely find bridging – that is excess mortar forming a bridge between the brick veneer and wall materials.

            You indicate that the problem was particularly pronounced on the southwest side of the house. That is commonly the case as our hardest, driving rains tend to come from that direction.

            Your mold expert is likely to be correct that all the wall area is mold infested.  I would not be surprised to find mold growth in other walls of the house, particularly the south side.  As such, a more intensive inspection is desirable.

            The only way to fix the problem is have the brick veneer removed and replaced.  If your house is out in the open, it would not be desirable to replace the brick veneer with newly-applied brick veneer.  Such brick veneer houses are particularly vulnerable to wind-driven rain, water intrusion, and of course mold infestation in walls.

            You could use vinyl or concrete panel siding.  The former is more prone to wind damage, the latter is less so.  Cement panel siding contains cellulose fibers and can become mold infested if it is not properly installed.

            You indicated that when the wall was open you found wet cellulose insulation.  I assume that this was wet spray-applied cellulose insulation.  If it was, it is a significant potential mold source and exposure problem independent of brick veneer.  Water intrusion through the brick veneer would, of course, make the cellulose insulation mold problem much worse. If you have such a product in the sidewalls of your house, it should be removed and replaced.

            Unfortunately, it appears that you need a major remediation effort to correct the problems described.

 

August 26, 2005