# Drainage for 98 yr old stone foundation



## OCRS (Apr 29, 2008)

I was wondering if you guys could give me suggestions on directing water away from my foundation. My understanding is that it's risky to excavate the soil on the exterior that's been against my foundation so long.

I've installed new eavestroughs and will have the necessary grading. My intentions are to excavate down 12", fill as needed for grade, put down some sort of ladscape fabric or 6 mil poly, add 6" of clean fill with a high content of clay, compact, then add 6" of top soil.

On the interior, I've put in a socked 4" big o and surrounded with gravel. This dumps into the old sistern and then pumped outside, hopefully soon to a catch basin.

Does my idea of the fabric/poly makes sense? I'd like to stop the water from getting under/through the foundation in the first place. I'm sure that it's bringing soil with it and the idea of having empty voids under the stone concerns me. 

Any advice you might have is greatly appreciated.


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## denick (Feb 13, 2006)

OCRS,

It is difficult to answer your question without seeing the type of stone construction of the foundation. Stone foundations come from the oldest where the stone are just rubble layed. Next, stones on the interior face are set in lime mortar and backed with dry layed, or rubble filled stone and when they reached the exterior grade they mortared both sides. And then stone that is mortared throughout. these are the three basic types but there is everything else one can imagine out there.

If you had some pictures of the inside and out it would be a big help in answering you correctly. If you were able to dig down out side 3' or more in one spot to see what the outside wall condition is would help. Just backfill the hole slowly and tamp it back in every 4" or so.

To answer some of your questions, It is only risky to excavate the ouside of a stone foundation if that foundation is in poor condition. Or it is one of the ones where the outer wall is rubble dry layed.

Your idea of the subsurface drain can cause more problems than it might fix.
When thinking of basement water problems you need to look at the two types of water action. 
The first is surface water. If rain water can penetrate the soil near the foundation and move down the outside wall it can find a way in if it exists. This is solved by regrading around the outside with a positive pitch away for 6' or more and well tamped earth. Problem houses we install a drainage fabric on the surface against the foundation extending 3' out. We then cover the fabric with a decorative 3/8" stone. Make sure all downspouts are piped well away from the building.

The second is underground water. This needs to be addressed with drains or pumps.

There's alot more to it but this might be a start.


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## OCRS (Apr 29, 2008)

Thanks for response Nick. I'll post the pix asap. I was curious though as to the detriments of the poly/fabric idea.


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