So I live in Canada, where winters are cold, and where there's not much soil above the bedrock. I would like to build a sturdy structure for an existing "shed" (in fact a 100-year old former stable or something) that's about 4m by 5m (12'x 15') and that's kind of collapsing. Currently, there's no real structure to speak of: it's only 2-inch thick boards piled up and nailed together, with small posts (like 2x4s) in the corners, resting on slabs of cement or something, each one about half as big as a basketball.

There's only about 60 cm of soil above the (granit) bedrock, and I was considering pouring concrete "posts" to rest directly on the bedrock, then using them as a basis for my structure (placing a metal plate on top that I can put a wood post on). My neighbour says that in the spring the meltwater will accumulate over the bedrock and may damage the concrete posts. Also, I would guess the ground probably freezes down to the bedrock in winter.

Any thoughts about this? alternative solutions? Note that I don't want to take the shed apart because it's 100-year-old wood and I think I would inflict substantial damage to it.

1 Answer 1


Piles to bedrock (essentially what you are proposing, albeit with really short piles) is an excellent foundation. I'd suggest drilling some holes in the rock so you can pin (with steel rebar) the base of the concrete post/pile into the bedrock.

I don't think you'll have any issues with the freezing - it will happen, but the bedrock isn't going anywhere, and the building set on piles set on bedrock won't, either.

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