I am a first timer at this site and was wondering what your opinions are about treated wood foundations. Do any of you use them? If so, why do you use them? If not, why don’t you? Do you think that the general public will ever accept wood as a foundation material?
I would appreciate some feedback on this topic.
Thanks,
JR
Replies
I don't really know of anyone who uses a wood fondation anymore, treated or otherwise. It's simply not as good a material as the traditional poured, stone or block masonry. Remember wood is still an organic material, even if it has been treated, stone and cement is inorganic. If you are introducing organic material back into the ground it will give out long before inorganic.
I have come across wooden pilings in older homes that were either soaked in creosote (ah that old smell), and some were simply solid black locust which is used as direct burial fenceposts much of the time or I came across one old Victorian in Nyack NY that had several aromatic cedar pilings for the front porch. They were still good!
I suppose in the very dry regions of the US like Arizona you might get away with wood but not where I live certainly. Besides, are you wanting to waterproof this fondation?
Thanks for your comments.
I agree that wood just doesn't make a lot of sense. I understand that it can work and under the right conditions, could last a long time. However, I think a builiding should last, given proper maintenance, virtually forever. I am not convinced that wood, even with treatment, would do that.
Thanks again,
JR
I built an all wood foundation for an engineer about 11 years ago. this guy wanted to get going soon and at that time it was impossible to get a concrete guy. They were months booked up. With this system you can build with carpenters.
The guy gave me a manual and we went at it. No problems except for leveling the walls. You build the walls on gravel and we leveled the gravel as best as we could but we still had to use the very low tech sledgehammer to beat down the high ones. And the engineer would have to come out just when we were doing this(us carpenters like everyone to think we are supersmooth).
But everything turned out just fine. I call the engineer up every once in awhile and he said the foundation is warm and dry(another advantage of a wood foundation is that you use 2x8 studs which can be insulated very well).
I don't know if I would use this system for my own house however. I don't think it saved that much money (the manual said it did at the time). I would also worry about the longevity of the system and if you could sell the house in the future for what it is worth.
I do not use PT lumber for a lot of reasons, prime among which is the poison with which they are treated being pretty nasty stuff to have around. The new generation of PT is supposedly less toxic, and uses organic (petroleum is organic, too, though!) toxins in lower concentrations than the older CCA, but I still prefer a naturally rot-resistant wood by far. Cedar and hemlock are two species with high rot-resistance. There are others.
If I were constructing a small barn, shed, or other outbuilding and budget was very tight, I might consider using a wood foundation. I would be very hesitant to use one for a house, as IMO a house should be built to last for a hundred years, minimum. I know some woods that can last on their own for twenty or thirty years buried in wet earth--but I have no direct knowlegde of any buried wood structure surviving a hundred years.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Go to the advanced search function (top lrft of the page) and ask it to find wood foundations for ya...
Awhile back there was a lot of in put on them...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....
WOW!!! What a Ride!
In the eighties (Alaska) we used them allmost exclusively. Around here (Ohio) there is far too much clay in the ground.
I'd use them on sand and gravel, especially a crawl space.......
I agree with JJ. If you back fill with clean gravel and have good drainage then a wood foundation should last a long time.
My two cents, Dave
My parents have a house near a lake here in Mn. and the ground they are in is clay and we have been slowly digging out the foundation backfill and replacing it with draining material . I have been surprised at the over all condition of the plywood ( Marine grade no douht) No dought that the pressure from clay over time would do a foundation like this in. So imho I would say that drainage and backfill material are of most concern to the long life of a wood foundation.
I built a wood foundation for a walk-out basement on a concrete footing with two #5 rebar because of sandy soil i was concerned about. I built 8x8 sections with treated ply sheets screwed onto the bottom half. Then i called in a couple friends to help me stand up the sections, shoot them down to the footer, and splice them together with the second row of ply and cap plate. I could have used bolts to the foundation, but i figured between backfill and the concrete floor poured inside, they wouldn't shift anywhere.
I lined the outside with plastic dimple fabric from Dorken as my waterproof layer, and ran French drains to daylight at the level of the bottom of the footing. I backfilled with the surrounding sand, but if you don't use a slip sheet of some sort, you can pull the dimple fabric down with compaction; i used demo'd 1/4" paneling in this case.
I made 2x6 walls, 16" OC. Ply was 5/8". All was treated to the .60 level for ground burial. I haven't had a bit of water come the foundation at all in four years, but i insulated the bays with foam sheets for an extra margin of safety.
The only problem so far is that the treated 2x6s shrank rather a lot, and not all the same amount, but up to 3/8" difference. I had to strap the walls to get a perfectly flat, smooth drywall finish. If i had this to do over, i'd work some iron flitches between the plates over the window openings, too, as i had a bit of inward bow there after backfilling.
The cost of wood v. concrete, materials only, was similar when i constructed this, but the labor and machinery i didn't have to hire made this a simple decision. I haven't noticed any health problems from living here, but i was religious about dust masks when cutting the stuff, and it's nasty on your hands, too.
We had a wood basement/foundation built by Woodmaster of Prescott, WI. Eight inches of washed 3/4" gravel on sandy soil. 2/8 studwall on 2x12 plates, 5/8 cca plywood walls, covered outside with 20 mil plastic. Also plywood floor. Walls built in sections in the factory and delivered by truck, set with a boom, 3 men four days. Very nice and warm, dry, easy to insulate and finish. Really liked it until the house burned down, including the foundation walls. We now have poured concrete. But contact Woodmaster for their literature.