permanent wood foundation

[jdtuttle]

Another alternative is precast concrete forms. Superior is one manufacturer that comes to mind. http://www.superiorfoundations.com/

[Meadows Miller]

Gday

I'm not a big fan of concrete slab foundations as over here we have very reactive soils and termite problems all but 2 of the 25+ Log ,timber frame and stick frame homes I've built since i started building at 13yo have been on stump timber framed floor systems  What happens here with slabs is that they get ground heave and get very fine (un-seeable to the eye) cracks and because there is very high moisture under the slab system (which termites need to survive) they will access the crack by spitting acid into the crack and following it up into the home even when the builder has put in the rite protective barriers 

At least with stump systems at least 18" G/clearance you can get under and inspect for problems and insects and being up of the ground it stays dry under the home  I think unless you are putting in a basement concrete is just a waste of money as you have to dig foundations , Reo ,boxing and all the other associated costs before the cost of the concrete 

Now if you do decide to go with a stump system under your timber frame you can go with a wide span system using 6x6 through to 12x12 stumps Ive built a 2200 sq ft place that only had 12 8x8" stumps under the whole home  only took us two days to build the whole floor system including laying a chipboard floor to work off     

With the lifespan of timber if your worried about longer life get the longest lasting local or P-treated timber and give it a good coat of creosote as most rot shows up within the first 8" under ground level as the oxygen levels are higher in that area of the soil or you can go for concrete posts 

Regards Chris

[robbshowe]

I an very interested in the idea of stump wooden foundations.  Can someone please explain exactly what the are?  I am guessing they are some form of pile foundation but using wooden stumps in place of reinforced concrete pillars.  I'd expect to have to use a wood similar to that use in harbours for jetties - highly impervious to moisture!  Any advice or photos would be greatly appreciated.

[Dan_Lambert]

I am interested in learning more about this foundation system, as you have described it. I am working toward building a TF home, and here in the southeastern US, we have a similar problem with moisture and termites.

I had intended to design the home to be built on timber piers, and standing about 18" (minimum) off the ground. My main reason originally was that I wanted to minimize the environmental (and, of course, the financial) impact of foundation building on a severely sloped lot. I also like the idea of being able to work under the building for inspection and maintenance reasons, as well as the fact that there is a good area of dry storage, if the building site permits it.

Any additional information I can obtain on this is very helpful, and much appreciated!

Dan

[Meadows Miller]

Gday Dan & Rob

Ill get something together for you  If you can get a hold of a Timber span tables book it'll help alot  Dan with the Timber Frame I'd just look at making your stumps at the same centers of your frame posts  and if you can house the floor joists into the sill timber you can span up to 1/3 to one half of the width of the building most of the wide span floor systems i have done have been around the 30' mark wide and done in just 2 spans meeting at a center sill the same size of the perimeter beams 
Ill organize some pics also  fellas 

Regards Cheis

[shinnlinger]

Probably not the same league of construction here, but I've considered auguring in some telephone poles for a shed I'm thinking of building and cutting them all level.  A concern I would have with this type of arrangement is the bearing ability. A simple shed is one thing, but a three story house bearing on a post in the ground without a sufficient base is another. 

[jander3]

Foundation on Stumps.

The second video on the following blog page shows the stump layout:
http://peelinglogs.blogspot.com/2008/12/video-tour.html


 



Dug 18" diameter holes that extended below the frost line, filled the holes with sack-crete and rebar, and installed a 6" piece of 18" diameter sonotube at the top of the hole (to provide a level surface).


 


Cut oak stumps, drilled holes in the stumps to accept rebar, and then cut the stumps level.




Floor support beam and joist work in progress.

[ljmathias]

This came up in a different thread but when you slice "cookies" like that, even relatively thick ones like yours, won't you get a lot of through-checking that basically splits the stump in one to several places?  that would mean that your beam may be sitting on a fair size hunk of wood... or may not be, no?  Sorry for the ignorance, don't have any experience with sliced wood (kinda like sliced bread, I guess), just the old 'french loaf' or 'subway sandwich' type of making something from a log.

Lj

[cheyenne]

I don't understand the stump cookies. Why not just set your sono tubes height with a transit, fill the tubes with crete to the top, lay your sills on the crete with a rubber pad in between.....Cheyenne

[den]

I find this to be a very interesting subject.
Has any one used a system for a garage that you dig (auger) piers every
6' to 8' apart then fill with concrete add a bolt(s). Then you double up on PT 2X10's
on edge and frame out on the piers...you may have sandwich PT 1/2" plywood
...to get 3-1/2" thickness. The floor is poured against the 2X10's
Then stud out your walls on top of the 2X10's that are on edge.

25 yrs. ago I dug piers and filled with concrete then formed a lintle, 6"X8" around
the perimeter. Then I put 3/4" foam in the bottom for frost heave. I then layed one
coarse of 6" block on top of the lintle. This was for a two story barn. So far not a crack.

[ljmathias]

Not sure I am picturing that method correct- you basically have a 10" slab with 2X10" dividers where the walls rest?  No problem with moisture seepage up through the cement-wood interface?  No problems with wood rot? Even PT will eventually rot away if in constant wet-out conditions...  Seems like long-term trouble waiting to happen, and with all that concrete you poured, why not just do a slab-on-grade and build up from that? Shoot, you could make it 10" thick and drop tanks on it from the second floor without cracking it...

Lj

[den]

A contractor was giving me a bid for a garage.
He said they put Big Foot piers in, put 2X10's on edge on the piers.
Thats what the wall plate sits on. Then fill in around the 2X10's inside and
outside. The inside would be 4" or so below the top of the2X10's for the
concrete floor. I've never seen this done.
Code says if I went with concrete, the bottom of footer has to be below frost...36"
That means a footer and blocks. The other option would be pole barn style construction.

The reason 25yrs. ago I built the two story barn like I did, is because everyone
said the continues lintle wouldn't work that it would crack because it was on the top of
the ground.
They didn't say how many year it would take to prove them wrong.

[Stephen1]

Hello all,

do any of you have experience with a permanent wood foundation? I wondering if it could be used for tf... I am interested in the flexibility and ease of insulation of this system and the fact that it can be owner built. The only issue could be the weight of the building...

thanks

Alexis

Alexis, my cousin built a beautiful house with this method, why? so he could do it himself, and it was cutting edge. well after 15 years in the early spring when there was lots of runoff, guess what collapsed the wood basement wall, what a mess in the basement, 20' of a 30' wall let go, mud, water, did I already say what a mess, and the expense trying to fix this while there was a half load limit on the roads as he tried to bring in fill after they rebuilt this wall. They then had to repair all the upstairs walls above it as the Sheetrock all cracked. He still has this foundation but after a few beer I can hear him saying what a mistake he made, in fact he calls it the biggest mistake he ever made in his life.

if you want something that is easy for owner built, flexible, and easy to insulate I highly recommend you look into ICF they are everything you ask for already insulated, strong, concrete, and easy to finish.
Stephen

[Meadows Miller]

Gday

  Wo Stephen thats a sad story mate 

I wouldnt recomend putting a basement under any stump systm  i woulda just done a Tanked poured concrete foundation under it from the start  we dont see many basements here as we have plenty off space for sheds (a blokes sanity if he has a missus  ) and the weather aint that cold 

Reguards Chris

[barbender]

With a wood foundation you cant just backfill it and forget about it, you shouldn't have that much wet soil against ANY foundation. The water has to be able to pass through to your drain tile, or better yet, your site should be sloped properly so that the water runs away from the building. I've seen block basements cave in too. Those ICF foundations are spendy, especially now with concrete at $115 per yard for 4000 psi, I don't know what mix they use for walls.