u/weatcoastgrind

I am building a small shop in my backyard. The end result will look like the first picture. Single course cmu foundation. The wall will be 2x4, and the sill plate is 2x8 to cover the top of the block. Sill gasket will be used.

Is it necessary to use pressure treated lumber.ber for the sill plate?

My concerns are shrinking and having the pt sill exposed on the inside. Do I need to account for wet pt lumber shrinking when laying sill plates?

I also want to paint or trim out the interior edge of the sill for appearance purposes, and I don't want any chemical off gassing.

I am located in Western canada, and it does rain a lot here.

Please advise. Thank you!

Looking for advice on how to build my shop. The shop foundation is like you see in the pictures. It will be one course high with core fill and rebar.

The walls will be 2x4 framed.

My questions:

1. Should I use an 8 inch sill plate to cover the entire top of the block? Bolt it down, then nail my 2x4 wall on top. Resulting in a double sill plate?

2. The shop will be insulated and finished. I do not want exposed anchors bolts like in the first picture. How best to position and hide anchor bolts?

Using a double sill, I could recess the bolts into the first sill, or notch the second sill? Do the bolts need to be exposed for retightening before insulation?

Please advise. I want to build this right!