# How to deal with rotten exterior wall behind brick?



## nnbis (Aug 21, 2010)

We are trying to do some remodeling of a half-bath in a newly-brought house, then we ran into a tricky problem 

The previous owner obviously did not try to take care of it... there are apparently at some point some serious leak, but all he/she did is replace the vanity and put on new tubes. We took out the vanity and saw some pretty damaged drywall, and cutting out those, we found that even the exterior sheathing are rotting. Those rotten boards (not sure what exactly it is, but definitely not plywood but some kind of wood composite) are so rotten that they can be easily pulled out by hand.

We took out some 3/4 of the wall in height. Not entirely sure what do deal with it. It is an exterior wall with bricks outside, and we certainly want to avoid having to take down the bricks at all cost! 

I attached two pictures.

We are thinking of putting some support between the studs (attached a sketch below). Do you think that would be acceptable?


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## BigJim (Sep 2, 2008)

Why would you want to put support between the studs? That is not the problem, the problem is sealing the moisture from the outside. (I am not trying to be a smart alack) It looks like the builders put brown board or bad black board up for sheathing. Good black board would have held up in my opinion as it is tar like impregnated which should resist moisture. 

The problem to reseal from moisture is going to be with the wall ties nailed into the studs. Wall ties are flat corrugated galvanized pieces of metal which are nailed onto the studs and bent over into the mortar of the brick to stabilize the brick wall. Tyvek would be the best way to go except the wall ties will be in the way. I do not know if you can remove the wall ties, you will have to ask one of the masons on the forum. I just built houses, I left it up to the masons to do the brick work. 

This is going to be tough to do but I would get all of the brown board out and dig it off the face of the studs but don't cut the wall ties. Once you have removed the brown board and roofing nails. I would cut foil back styrofoam sheathing and slide in between the studs and the brick. You will have to notch for the wall ties. 

I would be sure to use a good caulk or some good sealant to seal the edges of the sheathing as you install it against the next piece of sheathing. I would squeeze a liberal amount of the sealant in at the notches for the wall ties. 

Once you have the sheathing covering the wall at the brick you will have joints between the studs. Cut pieces of sheathing to go from stud to stud and from plate to plate and caulk all the way around each piece. I know this is tedious and hopefully someone else will have an easier way to help you but this is the way I would do it if it were my home.


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## jklingel (Dec 21, 2008)

Just speculating....Your problem may have come from the inside, too. If your interior wall was not air sealed, then moisture could be migrating out, hitting the cooler brick, and condensing. Whatever you do to repair/replace, be sure to install a good air barrier system that is vapor permeable, so moisture can go both ways. see buildingscience.com or greenbuildingadvisor.com for ideas. Gasketed, caulked sheet rock w/ later air barrier paint may work fine. Good luck with this one; it looks real nasty.


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## federer (Aug 20, 2010)

any update? whats the best kind of wall to use in a bathroom-cement board?


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## Thurman (Feb 9, 2009)

"jiju1943" 's method sounds very close to what I have done to repair this problem. And may I add, I have only seen this problem in bath areas so it is a moisture control problem, back to the post by 'jklingel". My last resort would be to take down a perfectly good brick facade wall. Check ALL of the interior wall studs for ANY rot--ANY at all. Mark each stud which has rot, particularly rot at the top or bottom. Check that bottom plate good also, is it pressure treated-probably not, should be. You may/should wind up building a temporary support wall about three feet back to hold up the ceiling rafters/roof load while you completely remove this damaged wall framing. Do save the brick ties. Cut each piece of sheathing for each space and notch for brick ties, use construction adhesive _for this application_ to install the sheathing. Sometimes the brick ties are long enough to nail to the side of the stud, sometimes I have had to use screws on an angle to secure them to a stud. Follow "943's" method for sealing and the extra piece of sheathing between studs. A vapor barrier on this one is a must, read up on this. Good Luck, David


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## BigJim (Sep 2, 2008)

I am sure the fellow who posted this has finished his bath by now but I had another thought that might do some good instead of trying to put the sheathing back up. Replace all rotten wood with treated and blow in the styrofoam insulation, that should keep the moisture out and like Thurman said the moisture more than likely is from inside since as it is a bath. Seal from all moisture where ever it is coming from and it should be good to go after doing all suggested.


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## Bondo (Dec 8, 2007)

> but I had another thought that might do some good instead of trying to put the sheathing back up.


Ayuh,... If your talkin' about that new sprayed in 2-pt foam,.... 

I love the Idea,...

Has anybody come out with a Diy'er type spray foam yet, say in the 100cf size or so,..??
I mean something other than Great Stuff in a can...


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