Grading question...”sloping property home”


Corporate Member
So my home is slightly built into a hillside/sloping property. We have a large deck off the rear of the house, and the grade underneath is inclined also. My question is can I safely dig this out and grade it flat? Do I need to worry about water seepage getting into my garage if I do? See pic and thanks in advance for your replies.


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Roy G

Senior User
Would you have to build a retaining wall to hold back the dirt? How much difference in elevation is there from one end of the proposed area to the other? Is your foundation level or is there a step in it because of the difference in elevation? I wouldn't think you would need to worry about water seepage if you removed the dirt.

Roy G


Senior User
I don't have a complete picture of what you are trying to do but I want to suggest a couple things to consider. First, you need to be sure that the slope of the ground is away from your house. If it isn't that can create moisture issues. You can add drainage but it is better to just slope the ground away so water is not collected against the foundation.

The other thing to be aware of is you need to maintain the necessary depth of your foundation. I don't know where your frost line is but the foundation has to be below it. If you remove earth that is against the house, you may be making the footers closer to the surface which could result in frost heave.

But if the result is the footers get deeper and not shallower and ground is still sloped away from the house, I don't see an issue.


I ran into some YouTube videos for home drainage issues and turns out these guys are in Greensboro. Call them and ask the pros ! I'll be building on a slope w/ walkout basement and want to call them out for preemptive assessment on how I should handle drainage.



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Corporate Member
Short answer - Maybe. Water can seep under the home on a hillside fairly easily.

The IBC code when a building is built requires that all ground is sloped away for the building a min of 2% grade for a min of 5 ft. this is where it gets fuzzy on a sloped hillside, even though the code calls for that it usually is never done on a slope such as your pictures. Further, the hill side if slanted toward the home will have a greater hydraulic potential. The underground water movement can be extreme.

The usual fix is to excavate along the home perimeter foundation approx 15-18 inches apply a vertical drainage mat against the foundation, that will provide both a drain and a waterproofing for the area.. Then a leach pipe in a french drain (gravel drywell) drained away from the building a min of 10' with it daylighting into a gravel spillway.

That is one of the best ways to do it,.......... or you could just use a heavy plastic mechanically fastened attached to the foundation and buried into the ground with a leach pipe routing the water away......... or you could just use a Bentonite product and paint the wall to water barrier the concrete and just gravel the area by the foundation.

To prevent erosion just use interlocking concrete blocks and make 3 elevations of them. That part is easy. There are some ideas to get you going


Pretty much what Oka stated, 2% grade in your flattened area, in ground drainage away from the home and retaining wall whereever you stop digging to hold back the remaining soil. With these steps I highly doubt you will see water in the garage


Corporate Member
Take a small diameter steel rod and push/hammer it down into the dirt right up against the wall and see how far it goes before you hit the footer. That will tell you how deep the foundation wall/footer is dug. Obviously don't excavate down below that level.

I would otherwise suggest that you get a professional to examine what you are intending to do. Structural issues could be exposed if you do it wrong.

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