Exterior Concrete: How To Properly Seal It

[Fore Man]

I'm building a home in CM and need a little help on how to properly seal the concrete 'stucco' covering our exterior walls. Normally, paint primer is applied over the raw, cured concrete....I realize this...but in my case we want to cover some isolated and small wall sections with brick applique'. These are the small brick-like trim peices that can be cemented in place in lieu of painting to add curb appeal. My concern is that our builder, whom I respect, explained that if we add these applique' pieces to our outside concrete walls, his experience shows that we can expect moisture to seep in through the wall (the wall is made of one thickness of built-up red bricks) and condense on the interior surface. His prior clients found it necessary to perform repairs to the interior wall due to this condensation.

I asked him if there was some kind of special sealant coating that could be applied over the outside wall surface to retard or prevent this condensation on the interior wall, and he replied "no, there is nothing available that will work successfully".

Does anyone have any personal experience in dealing with this problem? Many mooban homes here in the CM area use this brick applique' technique and I would like to use it too but am concerned of cousre that we could be asking for future problems.

Thanks

[chownah]

I don't know the answer but since you see people with this kind of wall then it seems like there is a good likelihood that there is a way. If you are asking your builder to install the applique it may be that he doesn't want to do this work and this is his way out of it and to still save face....just a possibility and might very well be wrong. Maybe try to find a contractor who specializes in this stuff and ask them how its done and then hire them....or....give it your best shot and go ahead and do it and see what happens since it is a small area it really probably won't cost much to remove, restucco, and paint in the future to fix the problem it creates....keep a close eye on it so you catch any problem quickly so mold or other similar problems don't complicate the issue.

Doesn't a latex additive make concrete less porous and thus more water resistent and could this be then put in the stucco mix to help block moisture?...don't know if this would work or not...also you could prime the stucco before adding the applique...and then put a clear sealer on the applique and reapply religiously as needed.

Chownah

[ozzydom]

If your referring to the "sandstone look"applique pieces,first off you give the section a coat of a sealer like Bondcrete which you mix with water, it looks like weak milk but is a plasticizer and concrete sealant and dries clear, then you apply the applique sections using Sikaflex sealant/ bonder .

Sikaflex comes in a cartridge and you apply it with a sealant gun and spread it with a notched trowel, just like laying tiles.

Home Pro and Tool Pro both stock Sikaflex,it is of French origin but instructions are in English,there are several types,just read the use description to get the one suited to your task.

cheers

ozzy

[ozzydom]

You can also give the completed applique facing a couple of coats of slate sealant,you then have 3 waterproof layers on the stucco,so moisture penetration should not be a problem.

[Fore Man]

Dear Chownah and Ozzydom,

Thanks for your posts and I appreciate your tips. Makes sense to me. My builder is a very respected one here and we have had had a flawless build so far--and nearing the end in a few months. I will suggest these ideas to him and if he still shies away then I can look elsewhere. He has done this kind of work before as one of the contractors for Land and Homes in Chiang Mai, so I was a bit surprised at this reaction whe I asked him to help us apply some sandstone applique tiles. to our concrete exterior. Cheers!