Ken Many of the old mill dams (1800's) were infilled cribs and one can still find the sound timbers in the rivers. I have read of using pressure treated plywood for foundations but do not know the life expentancy. Burning the wood would remove whatever it is that bugs and microbes go after...sugars? We USED to soak our fence posts in old motor oil and they seemed to last forever. It seems the more we try to defeat the natural order of things the worse it gets. A well layed stone foundation wall with well planned drainage is probably the lowest energy input system you will find but it is very high on the labor scale(another form of energy !) What about rammed earth walls with well planned drainage? Bob
While it may be possible to develop a good wood foundation system it would not necessarily work well in all conditions. I can see using a stone or masonry capped piling if dealing with soft soils or deep frosts. Where I am in Western Washington we have shallow frost and soils that may or may not drain (glacial tills and outwash). We also have more varities of mushroom than anywhere else in the world and same conditions that make that possible also cause wood rot...lots of it. I would consider stone but we also have seismic issues...so..concrete is my friend. Having said that, I'm sure that Bob and NH are right that the stone set posts last because air moves around the stones. I suspicion that this works very well for a while but what happens is that a debris cap forms and the rot starts at this "rot gasket" (local term). The one condition that compels me to think of sinking posts is to develop lateral strength (the ol' vertical cantilever) The last time I had to do this I thought of a possible solution (after the fact) which was to wrap the post in corrugated metal roofing, set this in an oversized hole with gravel in the bottom and pour concrete for bearing to undisturbed soil. If the metal was extended above grade it might at least stave off the debris cap effect.
the 4x6 will work if the plate is fully supported, say you are building of a concrete slab. If you are using piers then you might consider something a bit heavier. If you end up using the 4x6 then you just might have to put the floor joists on top of the plate. Although if you have a slab that will not be necessary. The lap joint will work just fine and is easy enough to cut. If you use a through tenon on your post that will also serve to secure the lap joint. There is also not as much ( almost none) tension on this joint anyway. Not compared to a tie beam.
Regarding the dimension and if one could call it a beam. It certainly is not but what you are going to be building is still a timber frame. So no worries there about stick/beam sizing. Many/all braces used in timber frames are not actually a beam/timber so why worry about a smaller sill plate?
Originally posted by Derek J Swanger: [b]4 by 6 is fine for sill plate TG. Less money and still a timber.
Bingo! That's what I was looking for! (Found out some great stuff along the way, though!) That along with Raphael's spread sheet works for me. Any disputes....? Ok. So then, what to do about the floor....? :rolleyes: I'll get to that later.[/b]
You could, similar to stick framing, put a 4x6 on edge and peg your joists into them. Kind of like a rim board. Then you can put your 4x6 plate on top of the already framed floor. Just an idea.
