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Community and Q&A

French drain/footer drain Q

kevinjm4 | Posted in General Questions on

Not sure what it’s called in your area, but my question is about the perforated pipe that runs along the perimeter of the foundation. In my application the pipe will be on the outside of the foundation and will be taken well away from house. And that is my question, if I need one given my setup.

im in zone 4c, and have a crawlspace with poured concrete foundation that is only about 12” tall. The sill plate is not pretty much flush with grade, with the grade very very slightly sloping toward house, but it really is pretty close to flat. So what I will do is excavate about 6’ from house, outward, and slope that down and away from house until I run into a new retaining wall I’ll put in 6’ away from foundation. That’ll allow me to have the dirt well below my sill plate and I’ll be able to control the slope away from house as well.

This side of the house does have gutters as well. So my question is, is a footer drain a good idea in this case? Or is it a little bit much. I’ve had mixed reviews given my application. But the one solid thing anyone gave me besides just a feeling was that if my house has gutters over where I’m talking about then a footer drain isn’t necessary.

laat question, if I do decide to go with it, does anyone have a recommended detail they can share with me? A link or picture… I looked for some on the website but they weren’t opening for some reason.

im looking for one that shows exactly where the pipe goes, and what materials to use around it, fabric, rock, etc.

thanks for the help!

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  1. Expert Member
    Peter Engle | | #1


    I'm not sure I completely understand the question. It sounds like this is an existing house, correct? if so, are you experiencing water issues in the crawl space now?

    I think you are describing excavating the exterior to lower the grade level around the house to the 6"-8" below the siding and sills that is currently recommended. That's worthwhile. If the new lowered grade slopes away from the house to the foot of a retaining wall, then you've sort of created a moat and this moat will fill with water when it rains. That's not a good thing. The place for the drain in this scenario is at the foot of the retaining wall, not at the foundation footing. Since you are diverting water away from the house with the grading, you want to collect that water at the low point of the yard. A gravel trench with perforated pipe inside would work just fine, so long as the pipe can pitch downwards to a daylight drain somewhere further downhill.

    If I completely missed the scenario, more information might help.

    1. kevinjm4 | | #2

      You have understood me correctly. Is this a good idea for my situation?

      The side of the house I am talking about is the addition side of the house that was put on about 25 years ago. Whoever did it though did not take into account the slight grade the house is on, and built the addition at the same level as the rest of the house. And the addition was added on the lower side of the house (in relation to grade).

      So when we bought it our issue wasn’t water in the crawl space per se, but was more about the dirt touching the siding. Which rotted the osb sheathing as well. That has since been replaced and my original post is my best idea to remedy a situation like mine. Currently there’s just a big trench there now to get the dirt away from the house and to preserve my new siding/sheathing...

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