Stone Foundation Scratch Coat??

EAE

This is a change order on a church basement remodel I've been plugging away at.

Walls in the men's room were rotten - so I demo'd to the stone foundation wall. The church-goers love it and want me to "fill in the big cracks with mortar or something and then paint it (the stone) white."

I've done my fair share of tuck pointing and tile work... but

Any suggestions on what to use to 'fill the cracks'?

I'm planning on using UGLI masonry sealer for the 'paint' and I understand that I need to start with a clean dry surface.

Thanks,

Chris

mdshunk

You are famaliar with how a wall like you describe aspirates, aren't you? You start "sealing" a stone foundation built with lime mortar and you can cause a whole boatload of problems.

Tscarborough

Look at the Big Brain on Sparky! S!

__________________
It ain't Rocket Science unless you are building rockets.

EAE

It will be a corner wall approx 5 ft by 12 ft and 7 ft high.

Can this be done?

mdshunk

No, not really. My area has about ga-zillions of stone foundations, and I've seen the problems hacks can cause. You've talked a little bit about it before, if I'm not mistaken, havn't you?

Tscarborough

Just a little.

EAE, first confirm that it is lime mortar. If it is light in color and soft, but not loose, then it is probably lime. If it was built before 1910, then it is almost certainly lime. You will have to use a lime mortar to repair it, and then let it breathe, i.e. not put a sealer over it.

If there are other issues causing liquid water to enter the wall, those need to be addressed first.

__________________
It ain't Rocket Science unless you are building rockets.

EAE

I don't think it's lime mortar. Called the contact for the church and he says the basement was dug out around 1950 -- replacing a crawl space. The mortar is dark and hard.

The seeping problem is being corrected by the landscape crew --I hope.

Provided it isn't lime mortar, is it possible to clean up this section? Any form of patch and paint/sealant will be better than re-framing it and letting it rot for another 60 years.

Thanks,

Chris

EAE

He could be mistaken though. -- would stone be used instead of block in the 50's?

Tscarborough

Stone is used today. It probably isn't lime mortar, in which case you can tuck it with regular bagged mortar mix, then seal it. Just be sure they fix the problem before you treat the symptoms.

__________________
It ain't Rocket Science unless you are building rockets.

EAE

Thank You.

Tommy C

Hey Tscarborough, I have a related question. Would it be problematic to apply an adheered veneer with regular mortar over a brick house (built in 1850's) that most likely has lime mortar on the original brick joints?

Tscarborough

It shouldn't be a problem, so long as the mortar is sound. How many wythes of brick?

__________________
It ain't Rocket Science unless you are building rockets.

Tommy C

Not sure how many wythes, but definitely multi wythe. Also, there are some hairline structural cracks due to settlement. In fact the entire rowhouse leans to the backyard slightly.

Tscarborough

Wait until the hottest, dryest time of the year to do it, and expect any moving cracks to mirror through. It doesn't sound as though lathing it is worth it, although that is the proper solution.

__________________
It ain't Rocket Science unless you are building rockets.

Tommy C

Thanks for the feedback, Tscarborough. This is a historically protected district, so there will be a LOT of red tape to go through on this one.