Just did a search for "foundation" in the forum and received nothing.

Although I am learning many things about building with wood, I do not know of foundation practices for timberframes. Its only as good as its foundation, right? Was wondering what types you all out there are using for the frames, pros and cons, etc. I would give an example but to be truthful I can imagine that you all have better examples from real situations.

Thanks,
mo

p.s. any input on the connections between the two would be appreciated also.

Many ways to do this, Mo. Things like soils come into play. Basement?

For all practical purposes I could not use a basement here in the lowcountry (loamy and sandy I guess). but elsewhere I would like one.

How are you enclosing the frame above the foundation? What we find is that if the wall around the outside of the frame is thick enough to provide decent R-Value, and if you want the outside skin of that wall flush with the outside of your foundation wall, then little, if any, of each timber frame post is actually directly above the foundation wall. Here's one possible design, using a poured wall foundation, SIPs, and web floor trusses:



Anyone feel free to jump in here and say what they like or don't like about this kind of solution. Obviously, I've done it this way before, but I'm always looking to improve the way we do things, or learn a new trick. CB.

If it were up to me I would lay up a nice dry laid quarry stone perimeter foundation and ste the frame on top of it, but the codes wont let that happen.Very interesting designs Daiku. I have actually never seen it like that before.I noticed there is not a sill plate? does the floor truss design replace it? What about poured concrete pilasters at the point loads in the frame and the 8" stem wall in between them. Perhaps someone could chime in about ICF foundations and if they might be used with timber frames, they always sound so alluring as they have such insulative qualities and the formwork is much easier and less labor intensive. tb

Daiku....we don't run our posts through the floor....We make sure the guy that did the layout for the floor truss system doesn't obstruct the posts....then we pre set the basement posts based upon owners preference....If its going to seen it gets a conventional timber...If its going to be sheetrocked...it gets 2x8 screwed...

The frame posts sit right on the subfloor...and screwed with GRKs from the bottom.....then it also gets attached to the SIPS panels which are screwed to the floor...We usually tack tar paper on the bottom to help keep them from wicking water is the site gets wet..

Mike:

I'm sure that's just as solid. There's enough bearing surface that the subfloor won't crush. Cutting the hole in the subfloor is a pain. We do it mainly to keep the post from moving around too much until we nail the straps to the posts. We usaully wait until the end to do that, so we can bump the bottoms around a little to plumb them up. We make the same choices for the basement posts. Solid where visible, built-up where hidden. Good idea with the tar paper. Do you guys do anything for uplift, like the tiedown straps? Engineers that I've worked with really love them. CB.

Simpson strong ties on the outside and 10" Grk's up through the subfloor from the bottom.

The other thing I think that is often overlooked on SIPS enclosed frames is the shear number of screws there are holding the frame to sill and screwed to the posts...especially the corners...

We use GRKs on the sill plates too....SIPS are screwed and glued to the sill plate and then screwed again through the sips to the posts.

Corners have additional lumber reinforcement in the SIPS that are screwed through to the post... I think the number of screws w/washers compared to the average clipped head nails holding OSB on the side of a house is pretty formidable...

If I had to ride out a tornado in a house...I'd want to do it in Timber Frame home that I built...

I've had that same conversation with several engineers. If they can make a whole house out of sips alone, and the way sips are anchored to the deck/foundation is adequate, doesn't screwing 20,000 lbs of timber to the inside make uplift even less of a problem? So why do we need additional anchors?

Whats is even more ridiculous is what they can get away with stick built houses ..... they only have one sheet of plywood on the outside that is only "clip nailed" Where a SIPS house has two sheets of Plywood that are glued and screwed to the sill plate.

The average SIPS house has around 20,000 screws in it and 8 cases of contractor sized sealant/glue/caulk....not including the big long ones we attach the panels to the timbers with....

Now add a well built timber frame inside of that.....

Compare that to your average metro stick built house....I definetly would rather be in a timber frame that I built...LOL