internal french drain can be installed in a no footing basement?

james_007January 14, 2011

We are thinking about put a french drain down to our full basement, about 7' below the ground. The house is a 1950's ranch house. The basement is poured concrete. There is no cracks on all walls. We are in Boston, MA.

There is no footing in this house. I found this from a plumbing project.

Because there is no footing, I am worry about the internal french drain project will weaken the foundation. During the installation, they will cut the concrete floor and dig a trench aside the wall then put back some gravels. those gravels and pipes will not as strong or tight as the original earth. Am I right? we do got lots of water from the wall-floor joints last spring during the VERY heavy rain because the water table was higher than usual.

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There is no footing

It's hard to believe that a home built in the 1950s in Boston would be missing footings. But anything's possible.

I don't like internal water handling systems since they do nothing to prevent continuing water damage, including undermining the foundation. But I suppose that as long as the trenches don't go below the foundation, they may not aggravate whatever support problems have developed.

    Bookmark   January 14, 2011 at 3:05PM
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james_007

we have done outside grading and we cannot dig from outside.

I will find out how deep the wall goes down from the floor and make the trench as shallow as possible.

    Bookmark   January 14, 2011 at 10:26PM
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wtrprfr

If your home has no footing than it is a monolithic pour. It would be a very bad idea to try and open the floor for any reason. Your only option, if you really cant dig, is to go with an above floor baseboard system.

    Bookmark   January 16, 2011 at 2:46PM
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james_007

I have opened few feet and found it is not a monolithic structure showing in the bottom link. The wall is NOT sit on top of the floor. The wall goes down few inches and I can see the floor and the wall were separate pour. I hope my understanding is right.

Here is a link that might be useful: monolithic

    Bookmark   January 16, 2011 at 6:59PM
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A monolithic foundation doesn't have to be a slab, as illustrated in this builder's blog where the footings and walls are done in one pour.

At the same time, it would be unusual to have a monolithic foundation enclosing a full-height basement.

If you dig down beside the wall in one section you'll find out for sure.

Here is a link that might be useful: Three Types of Concrete Foundations

    Bookmark   January 19, 2011 at 7:02PM
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aaa7483

same issue with my house. How did you proceed?

    Bookmark   March 9, 2014 at 3:34PM
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