I have a horse barn that I'm turning into an office. The walls are plywood coated with thin metal, and surrounded by a U shaped steel channel. They just sit directly on the concrete slab, and when it rains water splashes on the slab, and runs under the walls. What would be a good way to seal this so that water doesn't run under. My current best plan is to put a bead of silicone on the inside of the wall at the bottom, between the wall the the concrete floor. enter image description here enter image description here

  • What's the roof/eave situation look like?
    – Huesmann
    Commented Jun 28, 2023 at 13:34

2 Answers 2


It would be better to seal the outside, attempting to prevent water from getting in at all, rather than trying to stop it after it's already in under the wall and leaving it to soak the wall material from below.

Applying something to waterproof the concrete itself (outside) would also be advisable, as water will wick through concrete, particularly if it puddles on the flat sections.

Alternatively, considering the very different needs of a horse barn and an office building, you might want to consider adding insulation (may depend on local climate how much you'll need that) and a whole new wall surface, which you could arrange to have water drip off of beyond the edge of the foundation.

  • The only problem is the wall is designed with a u-shaped metal channel at the bottom. This has holes in the bottom, so water that splashes on the outside wall and runs down into the u-shaped channel has to then run out of these holes in the bottom of the u-shaped channel.
    – Hunter
    Commented Jul 5, 2023 at 15:17

I would seal on the outside with a UV resistant, water proof sealant, suitable for concrete and metal. Why let the water get in halfway and then try to stop it?

Or better still, seal inside and outside.

Even then some moisture might get in by soaking into the concrete. If this turns out to be a problem then there are silicone based sprays available that will penetrate the concrete and seal it off. They are not cheap, but are effective. I have used Acquron before, with success. I am not associated with it in any way.

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