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Hillside drainage around old stone foundation

Hillside drainage around old stone foundation

Hillside drainage around old stone foundation

Hello. I have an old home in SE Wisconsin. The original foundation is stone from the 1840s, and there were a couple additions around 1900, 1950s, and 1990s, where they added a mixture of cinder block walls, slab, and crawlspace under the newer parts of the house. It was built into a hill, with the slope side soil pushed up about a foot above the foundation with a swale about 6 feet out. The soil appears to be mostly clay, especially directly around the foundation.

We were recently told that we needed a French drain along the foundation on the slope side. However, after scouring the internet to learn more about them, this forum has pointed out that those are maybe not what we need after all.

I dug out the side of the house myself to at least get the soil below the bottom of the vinyl siding, but now I’m overwhelmed with figuring out the right course of action and don’t want to pay a contractor a ton of money for a wrong fix. I tried to call around for an engineer to look at it (recommended in an old home group on FB) but no one has returned my calls.

I thought that we could possibly dig out a bit further and terrace that slope or at least install a retaining wall. If we went that route, would grading the soil away from the house be enough without installing a drain there? Or does it still need a drain but just not a French drain?

There is nothing seeping into the basement from this side, at least from what we can see as this side is much harder to access. The major problem was simply that the vinyl siding was buried, so the sill and lower parts of the wall are now rotted, which is an entirely separate problem.

Here are pictures of it dug out so far and some before pictures. I can add more pictures or details or whatever is needed. Please help me figure this out without wasting more time and money.

RE: Hillside drainage around old stone foundation


What is your definition of a French drain? Mine is a post hole sunk vertically to below the frost line, approximately 48" to 60" for the Southern half of Wisconsin and then filled with clean rock/large gravel. Maybe including a sock filter to prevent fines from invading the hole. Which they will eventually, anyway. This allows free-draining of any water that enters the hole.

On your pictures, take 4 of them with one each of the four cardinal directions, showing the 4 complete elevations. As you take each picture, turn 180 degrees and take 4 more pictures of the ground going out from the building. The one picture of the slope running down to the house is a very good start, but back up and take a picture/detail showing a larger view of the slope. Take any other pictures necessary to show local details needed to understand the drainage situation.

Label all the elevations with their cardinal directions as well as the other four pictures showing the grounds extending out in the cardinal directions.

On the side of the house with the sloped ground draining toward the house, you might locate a swale approximately 15' to 20' away from the house with a slight ditch on the high side of the swale extending in a U shaped pattern around the house on the 3 high sides. You might also install an ABS drain tube below frost line also extending in a U shaped pattern around the house. This tube will drain to daylight on both ends if possible or a French drain if draining to daylight is not possible.

There are endless variations possible depending on the local situation. Contact a local landscape architect who understands drainage for more specific help.


The French drain needs to be sized in diameter so it will hold all or most of the water that enters it.

RE: Hillside drainage around old stone foundation

"French Drains" for me are a trench cut down to what ever depth you like, but typically 18 inchs to 2 feet, lined with geotex type material, then loose stone / large gravel for 6 inches, then a PVC perforated pipe laid at some sort of slope angle and then back fill with loose gravel. You can even overlay the top with turf if you want.

Looks to me to be exactly what you need in that area of ground you've just cleared or even right alongside the house.

I would get some sort of fall on your pipe and then connect to a soakaway beyond the house.

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