This shed has been in our property since 2009, it was installed on a concrete slab by the previous owners. One side of the shed is sinking into the soil where water pools up around it. We recently finished the inside of the shed with insulation and drywall for office space use. I'm concerned about moisture seeping into the subfloor and causing problems, as well as water damage to the siding.

  • How can I remedy this problem?
  • Would I have to invest in water drainage or would be the shed foundation have to be lifted up?

enter image description here

  • 1
    A soil bearing failure for a light structure like yours on a slab is very unusual. What sort of prep work was done before placing the slab? Was the organic-rich layer of surface soil removed? Was there any gravel brought in or soil compaction performed? And do you have clay soil? I don't see any hints of clay soil in the picture, but without "organics" or "clay," I'm totally baffled and asking about how you know that it's sinking.
    – popham
    Jan 10 at 2:44
  • Sorry - I used the term "sinking" for lack of a better word. I'm not sure about any of the prep work done unfortunately, as the shed was placed by previous owners. I was told it was placed on a concrete slab foundation, and I can also see it on the other side where it's not under the dirt. We definitely do have clay soil, though, it's just not clear in the picture. By "sinking", I just mean that the foundation is buried under the soil, as pictured, and I'm concerned of the potential water damage to the subfloor of the shed. Thanks for taking the time to comment further.
    – Maria
    Jan 10 at 5:44
  • Judging by your "one side" and the fence's angle with your presumably plumb wall, I assume you have good runoff drainage and you just need to move that puddle to the other side of the office so that gravity can take it. From your image the ground looks pretty level running parallel to the wall. Is there a significant elevation difference between the ground at the two ends of the office? Not right next to the slab. Is there a significant elevation difference when you go 5 ft to 10 ft beyond the ends to check? An image capturing the whole wall plus those 5ft to 10ft at each end would be helpful.
    – popham
    Jan 10 at 6:25
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    – isherwood
    Jan 10 at 14:21
  • We need photos from all sides.
    – Huesmann
    Jan 11 at 13:53

1 Answer 1


The most effective option is absolutely to provide adequate drainage around the shed.

If you dig close to the footing (without undermining it), then you put in good drainage next to it. And you can waterproof the concrete from the outside.

And then waterproof the floor from inside.

  • Thank you for your answer. Much appreciated! How would I go about waterproofing the floor from the outside/inside? Would appreciate any suggestions. On the inside, we put a vapor barrier on the subfloor over the concrete slab, and added rockwool insulation on top, underneath the floorboards. The shed is finished on the inside with insulation & drywall, so I'm extra concerned over any potential water damage. Thanks again.
    – Maria
    Jan 10 at 5:45

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