Installing French Drain And Dirt Support Wall

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MandMLawson
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Joined: Fri Apr 28, 2017 3:10 pm

We purchased a manufactured home that sits on a hill. See the attached picture. The ground slopes from front to back and from left to right. The front left corner is about 18" high and the back right is about 60" high. I want to put in a French drain across the two high sides (left and front) to channel water around the house instead of under it.

Rather than dig down into the existing sloped soil, I was going to add dirt to build up the ground so it was more level across the front, placing the drain in as I build it up. I felt this would help prevent water flow under the house by (A) adding the drain and (B) negating much of the slope towards the house. Feel free to comment on this plan.

The question I have is not about the plan as much as it is what type of foundation/support wall to build to hold the dirt back from wanting to go under the house. Should it be a poured concrete footing type of barrier or would cemented concrete blocks work or something else all together? I would assume a moisture barrier for both would be advisable to prevent direct contact with the dirt on the concrete / blocks. I was hoping to build the wall directly under the edge of the house so I could install new skirting that would rest directly on this surface.

Any advice and guidance in this would be greatly appreciated.
Attachments
Picture of slope along the front of the house.
Picture of slope along the front of the house.
20170130_113839_smaller_2.jpg (212.43 KiB) Viewed 3714 times
Mark440
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Joined: Tue Feb 26, 2008 8:33 am
Location: Anna, Tx

First - I feel your pain! WHen I bought my place, the fool who set it piled from 12" up two 2 feet of dirt up against the skirting. Behind the skirting was a hodge-podge of wickets and pickets to keep it all from collapsing. And then along came a big, big rain...and it did. It was one heck of a mess!

I decided early on that keeping the water at bay would involve a 'terraced' look. I have a compact tractor and used the FEL and box scraper to cut a swath into the high sides. All of it is sloped slighty away from the house, and also from high to low as the yard goes. I put in retaining walls with the 12" stackable blocks to shore up the dirt.

It came out ok and keeps the water away.
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Greg
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I would not build up, When you do have a problem you will only be compounding it. I would drop the grade down and make a path for the water to flow around the home. You could make a raised well around the tree to save that and grade around it. Also by building up you will reduce the air flow under your home increasing the risk of moisture damage from ground moisture.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."
MandMLawson
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Joined: Fri Apr 28, 2017 3:10 pm

Greg wrote: Mon May 08, 2017 7:37 pmI would not build up, When you do have a problem you will only be compounding it. I would drop the grade down and make a path for the water to flow around the home.
Greg, thanks for the advice. Because of the height differences I figured there would be a problem with grading because of the amount that will be required, and the possibility of dealing with power, phone and water.
Greg wrote: Mon May 08, 2017 7:37 pmYou could make a raised well around the tree to save that and grade around it.
Can you explain or provide a URL to an example of what you mean by a raised well?
Greg wrote: Mon May 08, 2017 7:37 pmAlso by building up you will reduce the air flow under your home increasing the risk of moisture damage from ground moisture.
Building up the level for the french drain was only going to be on the left side and front. These have the lowest height already (compared to the right and back). I have intention of replacing the skirting with insulated panels and have plenty of automatic vents. I figured those would more than compensate for any loss in height on the two sides.
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Greg
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Trees are sensitive to grade changes, Often a well or mound in your case is built around the tree to protect the root system from exposure in your case or smothering if you were going to build up the soil around it. there is a formula for the size, but I would guess a 20' diam. should be plenty.

My biggest concern with building up the area aside from the airflow is trying to get under the home to do any work.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."
MandMLawson
Posts: 11
Joined: Fri Apr 28, 2017 3:10 pm

Greg wrote: Wed May 10, 2017 8:12 pmTrees are sensitive to grade changes, Often a well or mound in your case is built around the tree to protect the root system from exposure in your case or smothering if you were going to build up the soil around it. there is a formula for the size, but I would guess a 20' diam. should be plenty.
Funny you should mention that. The picture is a few months old and I have since cut that tree down. It was growing towards and over the house. So it is a moot issue at this point. :)
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