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-   -   Old stone foundation and no footers (http://www.diychatroom.com/f105/old-stone-foundation-no-footers-158819/)

Wayne Perry 10-03-2012 08:55 AM

Old stone foundation and no footers
 
My daughter and son-in-law bought an old farmhouse built in the 1800s, and I've been helping them with some renovation. As is typical, the original house has been added onto several times, but the original part sits on a stone foundation. Surely it originally had a dirt floor cellar with a low ceiling...I've been in plenty of them over the years. However, it looks like the owners at some time in the past 100 years or so decided they wanted a concrete floor in the basement and more headroom, so they dug out the cellar floor. Now there's headroom and a concrete floor, but they dug down past the foundation...all around the perimeter (about 20' x 30'), there is about 6" of soil underneath the stone walls.

The walls seem true and sturdy, although in need of re-pointing, but the problem we are dealing with is that every time it rains, water seeps in through that soil band in several places. We have corrected the gutter system and grading around the house (a severe problem originally), and have even laid perforated drain tile to absorb surface water and direct the runoff from the down spouts away from the house.

So I have questions around 2 issues...is there a way to strengthen the bottom of the foundation from the inside...the original house is surrounded by additions, so getting to the outside of the original foundation is impossible? Also, what is there left to do to address the water seepage problem? Any ideas are appreciated...they (we) are completely frustrated.

Canarywood1 10-03-2012 10:37 AM

Quote:

Originally Posted by Wayne Perry (Post 1022765)
My daughter and son-in-law bought an old farmhouse built in the 1800s, and I've been helping them with some renovation. As is typical, the original house has been added onto several times, but the original part sits on a stone foundation. Surely it originally had a dirt floor cellar with a low ceiling...I've been in plenty of them over the years. However, it looks like the owners at some time in the past 100 years or so decided they wanted a concrete floor in the basement and more headroom, so they dug out the cellar floor. Now there's headroom and a concrete floor, but they dug down past the foundation...all around the perimeter (about 20' x 30'), there is about 6" of soil underneath the stone walls.

The walls seem true and sturdy, although in need of re-pointing, but the problem we are dealing with is that every time it rains, water seeps in through that soil band in several places. We have corrected the gutter system and grading around the house (a severe problem originally), and have even laid perforated drain tile to absorb surface water and direct the runoff from the down spouts away from the house.

So I have questions around 2 issues...is there a way to strengthen the bottom of the foundation from the inside...the original house is surrounded by additions, so getting to the outside of the original foundation is impossible? Also, what is there left to do to address the water seepage problem? Any ideas are appreciated...they (we) are completely frustrated.


I'd say to consult a civil or structual engineer for what needs to be done, definitely in their realm of expertise,there's a civil engineer on this forum that may see your problem and be able to give you some advice.

GBrackins 10-03-2012 04:08 PM

Seeking the advise of a professional engineer as Canary said is excellent advise.

We cannot determine on an internet forum whether the existing rubble stone foundation is stable or not. Like yourself I have some concerns regarding it based on the fact it has been excavated below the bottom of the wall on the interior side. if the soil below it were to "wash out" from water intrusion or by lateral movement caused by a seismic event or other lateral force you could have a partial collapse of the stones. Old foundations though can be a lot more stable than you can imagine.

chances are the engineer will want to construct some type of retaining wall on the interior side of the existing foundation if they evaluate the existing foundation as unstable. they may select either a cast in place reinforced concrete wall with footing, or footing with concrete blocks with reinforced grouted cells. that's up to them. they may even recommend replacing small sections at a time with a new foundation wall.

they money you spend on an engineer will allow you to sleep better at night. they will evaluate the existing conditions, determine if there is a hazard and a proper course of action. Better than trying all sorts of suggestions only to find out they were not needed, or were not effective.

Good luck!

Wayne Perry 10-06-2012 04:54 PM

I'm becoming convinced to surrender to hiring an engineer, in spite of the expense (holy cow!). Any thoughts on my water problem? Of course they are related, but I'm starting to think I should have put solid drain tile in rather than perforated. It's possible that using the perforated to run-off water from my gutters may be picking up some surface water, but it's likely putting it that much closer to the paths used for years and years by water seeping into the basement under the foundation Does that make sense to anyone? Is there a drain tile that doesn't have holes on the bottom...just on the top?

Canarywood1 10-06-2012 05:34 PM

Quote:

Originally Posted by Wayne Perry (Post 1025283)
I'm becoming convinced to surrender to hiring an engineer, in spite of the expense (holy cow!). Any thoughts on my water problem? Of course they are related, but I'm starting to think I should have put solid drain tile in rather than perforated. It's possible that using the perforated to run-off water from my gutters may be picking up some surface water, but it's likely putting it that much closer to the paths used for years and years by water seeping into the basement under the foundation Does that make sense to anyone? Is there a drain tile that doesn't have holes on the bottom...just on the top?

"It's possible that using the perforated to run-off water from my gutters may be picking "


I would try directing the gutter runoff further away from the house,than putting it into the perforated tile,there's a LOT of water coming off that roof,and see if it helps,but you'll still need an engineer to correct the foundation problem.

Daniel Holzman 10-06-2012 08:25 PM

If you have a high groundwater problem, you need to install a perimeter drain. The subject of correct installation of a perimeter drain has been discussed repeatedly on this forum over the last two or three years, do a search. The subject of which way the perforations go (they need to point down) has also been discussed repeatedly, check it out. Installation of a sump pump to keep a basement dry has been discussed many times, check those threads out as well, if you cannot install a gravity drainage system.

As for foundation integrity, that is a complex issue which depends on the soil type, foundation geometry, load, and groundwater level, and cannot be analyzed without an on site investigation by a competent person, so I concur with the previous posts recommending getting an engineer. If you feel the engineering expense is too great, you will probably not like the cost of hiring a contractor to perform the work either, but unfortunately this is specialized work and likely to be hard to find a low cost bidder.

Wayne Perry 10-06-2012 10:55 PM

If I could get to the exterior perimeter of the old foundation I probably would have already installed perimeter drain tile and a sump, but my unique issue is that the entire original foundation is surrounded by various additions built over the years, and I haven't found anything searching the board that helps, other than the advice to hire an engineer. The only way I have to get to the outside perimeter involves major demolition and rebuilding. The inside perimeter is just as risky according to some because of the potential compromise to the soil that the foundation is resting on. This is a real dilemma. I think my situation is testimony to being sure that things are done correctly.

Still, you've all given great advice and provided support for getting my daughter to pay now rather than pay later. Thanks.

Daniel Holzman 10-07-2012 08:13 AM

One option to consider would be to install a drain line on the interior of the foundation. This type of work is routinely done in basements, and might be easier in your case since it sounds like there is no concrete on the floor. If the pitch is available, you can go gravity drainage, if not you need a sump pit.

As to supporting a stone wall on a column of soil, frankly that sounds like serious trouble. One option would be to install a concrete foundation underneath the stone wall. Of course this is going to be tricky, potentially dangerous work, due to the need for support as you go, but this is pretty routine work for a competent foundation specialist experienced in underpinning work. Due to the specialized nature of the work, you are unlikely to get any bargain bids, and if you did, I would be very cautious about accepting them, since underpinning work tends to be slow, you have to be very careful not to damage the existing structure, and low bids often mean cutting corners, which is BAD NEWS in the world of underpinning.


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