How to attach a new sill to an existing concrete foundation

Question

I have a foundation of block wall. To get it to the correct height I need to put 4" solid block top cap on it and my sill plate on top of the 4" solid top cap. I can fill in the voids in the block wall where I'm going to need to bolt it down with cement.

My question is how best to secure the walls. If I bury a J bolt in there I'll have to drill a hole through the 4" solid top course that won't be serving any purpose for securing the walls so it's just a bolt going through a hole. I can't even seem to find a bolt long enough that would bury the J bolt in the cement under the 4" solid block in the cement filled blocked wall more than a few inches.

I'm thinking I'd fill in the block wall with cement where I need to anchor the walls and then go in from the top and put in a 1/2" x 6" tapcon (or longer if I can find it like 10") or something so that it uses the 4" solid block and a bit of the cement underneath for grip. Can't tell if this meets code or is even a good idea though.

Answer 1

The anchor bolts need to go well into the block, preferably at least 8" in. You should place the anchor bolts in the head joints of the 4" solid run. No need to drill holes in the solid block. Worst case cut the solid block where you need to and set the bolt in the joint created in cut block. They should coincide in a hollow place in the rows of block below often enough to work in a bolt about every 4' maybe slightly more if need be depending on your seismic area. Masonry supply houses carry anchor bolts 16" or 24" long. In my opinion, you should use a minimum of 16", again, depending on your seismic area. There are other types of clips that will do the same as a anchor bolt.

Answer 2

Planning on visiting Oz?

You need the J-bolts, and you need the j-bolts hooked on steel - the steel they are hooked to can transfer load down to the lower parts of the cavity/grout fill.

You'd probably be better off to pour a 4" bond beam with reinforcing rods (I suppose you could form it with 8x4x16 bond-beam blocks) rather than using solid blocks, and let that tie into the anchor bolt cavities as well. (6x4x16 or 10x4x16 if your wall is 6" or 10" thick rather than 8"...)

Don't let e.g. "what you can find at Home Depot/Lowes" limit your choice of block-type or anchor-bolt length. A real masonry supply should have long bolts, as Jack says - and bond-beam blocks as well.