Connecting ICF Foundation Wall + Timber Frame / SIP?
I’m planning to build a timber frame home soon (eastern white pine and SIPs) and have received a decent quote for an ICF basement.
I like the idea of efficiency in this combination and know that others have built this way but am a bit confused about how they connect? We are responsible for the foundation and first floor decking before the timbers arrive.
Does any one have construction details they could share for this (ICF wall, sill plate, first floor deck, post, blocking, and SIP positioning)? If not can any of you share your experiences with this?
Here are the specs on our materials:
Eastern White Pine post = 10″-12″ thick
7 3/8″ Neopor R-38 SIPs = 8 1/4″ thick (with OSB)
ICF wall with 8″ concrete = 13 1/4″ thick
Our timber frame company said they need at least 6″ of concrete directly below the posts. Is this enough? I’ve seen that some folks float the sill out to support the bottom of the SIP panels but it seems like it would require an extremely large sill/overhang on the outside?
Any and all input, guidance, and links are greatly appreciated!
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This video from G.O. Logic (part of a series) might give you some ideas.
https://www.youtube.com/watch?v=kFZlnRny38s
This might not be a lot of help, but I built an ICF home with a few areas of framing (ie window seat and dormer), and the garage foundation was poured using ICF with the above ground walls framed with 2x6s.
We used standard galvanized anchor bolts. These were placed into the top of the forms when pouring the concrete, just like any other foundation. Then we used PT sill plates, 2x6s in our case. I think we used 6" ICF for the garage, but the window seat and dormers were framed over 4" thick concrete in ICF.
For the floor joists, I would suggest also placing anchor bolts into the concrete - in this case in the sides of the forms. This will allow you to solidly attach ledgers to install your joists using hangers. When we did this, we cut about a 4" round hole around each bolt so that the concrete would span all the way to the ledger, around the anchor bolt. You can place the J bolts through some 2x6 scraps, screwed in to the ICF before pouring concrete. Alternatively you could just put up PT ledger boards using deck screws to the forms, with the anchor bolts installed, pour the concrete including the 4" holes right up to the ledgers, and then come back after the concrete has cured and tighten down the nuts on the anchor bolts.