When it comes to mortgage advice, some people recommend making an extra payment. The logic is :"These extra payments are automatically applied to your principal, not interest".

Why does it matter if the extra payment is applied to the principal and not interest?


Question: Can I rest cement posts directly on the bedrock to build a structure for a large shed?
Answer: 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.