Author Topic: permanent wood foundation (Read 4399 times)

Alexis · « **on:** January 25, 2009, 03:09:29 pm »

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

breederman · « **Reply #1 on:** January 25, 2009, 03:27:59 pm »

I live in a log house with 10 inch log walls sitting on a wood foundation. We have been satisfied and had no problems with it in over twenty years. The only concrete used was for the floor in the basement, so it makes for a very easy and flexible owner build . just be sure to have it designed for uneven loads if your back fill is not even on all four sides, and do not skimp on your drainage.
Just insulate and dry wall to finish the interior, makes that job so easy.

Brad_bb · « **Reply #2 on:** January 25, 2009, 07:53:46 pm »

Perhaps you should explain what it is, so that we understand?

breederman · « **Reply #3 on:** January 25, 2009, 08:30:07 pm »

It's a heavily pressure treated stud wall sitting on a compacted crushed stone footer, rather than a traditional block or concrete foundation.

cheyenne · « **Reply #4 on:** January 25, 2009, 08:55:55 pm »

Bet it made the building inspectors scratch their heads.....Cheyenne

beenthere · « **Reply #5 on:** January 25, 2009, 09:01:58 pm »

There have been a lot of them built. My son built one a few years ago. Has treated stringers with treated plywood for the lower level floor. Nice and cozy down there. I think the walls are 8", and with insulation, makes for an area easy to heat.
Don't recall any problem with code.
Do recall a problem with the new building inspector tho....couldn't move in until the garage floor was poured, as there might be a drop of oil from the car that dripped on the crushed stone.

Apparently no concern that the car sitting outside might also drip some oil.
Delayed his moving in for three months, while the ground thawed out under the garage floor area. That one item cost him a lot of money.

breederman · « **Reply #6 on:** January 25, 2009, 09:23:20 pm »

No problem with inspector, but back then, things were pretty lax. After the 1st inspection when we called for the next one he said to take a picture and cover it up!
We do have a walk out basement so it did need to be designed for the uneven back fill. If I remember right the long walls are 2x8 12 inches on center, and the un filled wall is 16 inches on center.

cheyenne · « **Reply #7 on:** January 25, 2009, 09:27:12 pm »

Is there a benefit to using wood as opposed to block...Cheyenne

breederman · « **Reply #8 on:** January 25, 2009, 09:49:08 pm »

Others can chime in, but to start: cheaper, can be built with regular framing skills and tools, warmer, dryer, easier to finish inside walls if it is a living space.

Alexis · « **Reply #9 on:** January 26, 2009, 08:21:39 am »

breederman named a lot of advantage,

one that is important for me: reparability. If a concrete fondation cracks ( I rarely seen an uncracked foundation) it has to be reparired with epoxy by a professional and it will not be the same strenght as before.

the wood foundation will not crack, and if there ever is a problem, it can be repaired like any other wall... rip the plywood, nail a new one... even if it's only good for 50 years, it's a one week job the change if after the 50 years and can be done by any carpenter...

Jim_Rogers · « **Reply #10 on:** January 26, 2009, 11:31:36 am »

Every concrete foundation will crack, that is a given. Many have studied this and the people who know and have made livings repairing foundations and other "builder" mistakes have written books about solving these problems by building correctly in the first place.

One such foundation crack solution is to score the foundation before hand so that you control where it will crack. This can be done by sawing the foundation inside the house after it has been poured and the forms stripped. Or by putting a strip of wood inside the form so create the seam before it's poured.
Then when the foundation cracks it cracks in a straight line and with prepared edges that can be easily fixed with epoxy. Rebar in the wall will hold it from separating.

Concrete is strong in compression, the rebar gives it strength in tension....
Foundation have to be designed and constructed properly....

Jim Rogers

shinnlinger · « **Reply #11 on:** January 26, 2009, 11:41:53 am »

Let me put in a plug for concrete....I realize concrete is the second most widely used substance on earth by man (first is water) and that concrete is very energy intensive. I applaud those that don't overbuild their foundations and am intrigued by the shallow trench insulated foundations that drain well, BUT one thing in concrete's favor is it tends to stick around (think Aquaduct) And Jim is right, cracks are seldom a structural problem if rebar is used.

How do these wood foundations get backfilled? I mean it wouldn't be so simple a task to replace the outer buried panel WHEN it rots out in 50 years and you are 80. Since it is buried, one might not even know they had problem until the studs rotted too and that could be life threatening. Do you put moisture detectors down there??? Who is going to be checking those in 50 year?

Sure, you can prolong this with membranes and such, but sooner or later it will rot. IF it rots sooner, any savings/lessened environmental impact will be out the window. If it means structure failure someone could get killed.

True, it probably won't be YOUR problem to deal with as PT will last a good while, and most houses don't go much more than 100 years so you might be onto something there if you objective is a disposable house, but what are the real savings? Your kids might inherit the house and I would be curious what appraisers think of the idea if your plan is to sell your house to pay for your retirement. Wouldn't it be unfortunate when you go to sell at 70 thinking it is your nest-egg only to find your house is condemned and worth nothing? I bet you wouldn't think you saved much then???

I also recall when I was 16 I was hired by the local lumber company (long gone) to work around the yard. The very first thing they did was had me dig 6 foot holes to set piers in for PT posts to support the deck of an addition they planned. I had dug about 8 of them when some one figured out it would be cheaper to pour a slab than build a wood deck (and this was a lumber company!) What impressed me was the bean counter that figured it out came out and helped me back fill. Point is really compare the savings vs headache of trying something "outside the box"

I will admit I was considering a strawabale foundation for my house. I was going to put telephone poles every 3 ft with a pT carrying beam on top and stack straw bales inbetween, form it and pour concrete around it to honecomb the bales. Poor mans ICF's if you will, but my buddies pulled an intervention and talked me out of it and I am glad they did...I think....

In a dry site the wood foundation is probably fine, but I like to consider the whole picture....

Just another way to look at it.

moonhill · « **Reply #12 on:** January 27, 2009, 07:53:25 am »

Some nice points by shinnlinger. One reason concrete cracks is shrinkage it is unavoidable and helped by Jims solution, a forced crack.

The PT used should be the higher grade PT, the stuff stocked in the building supply store is of a lighter grade and not intended for ground contact. It is a spedcial order. Am I right on that?

Tim

breederman · « **Reply #13 on:** January 27, 2009, 08:02:33 am »

yes. .6 as compared to .4 If my memory serves.

TW · « **Reply #14 on:** January 27, 2009, 01:13:50 pm »

I second shinnlinger. The foundation is the most difficult par to replace and should therefore be well made.

cheyenne · « **Reply #15 on:** January 27, 2009, 07:39:10 pm »

I don't mean to be a contrary but, I can't see where wood is cheaper thank block.....Cheyenne

shinnlinger · « **Reply #16 on:** January 27, 2009, 09:27:04 pm »

Alexis,

When you first asked about wood foundations you mentioned that your primary reason was ease of owner building.

If Ease is you main objective, ICF (insulated concrete forms) are the way to go. The can be shaped over ledge if needed with a bread knife, are very light, and lock together like legos. When filled with concrete they are effectively an R-50. Now they aren't cheap (but it never hurts to ask around) and you may have issues with Styrofoam/concrete environmental impact, but in my mind the impact is lessened by the permanence and high R factor...IF you can afford them.

If money is an issue, ask at the concrete plants for "seconds" My local place was selling blocks for $9 a pallet (Including the pallet) because they didn't want to leave them out in the snow and have to plow around them. Obviously at prices like that you can't go wrong even if you need to hire a mason to help you out.

I would have no problems living in a wood foundationed house, my only real concern would be resale value as stated earlier.

Jim_Rogers · « **Reply #17 on:** January 28, 2009, 08:50:56 am »

When using ICF, it is usually required that the inside surface be covered with sheet rock in order to make the foundation "fire proof". So these costs have to be added to the project....

Jim Rogers

shinnlinger · « **Reply #18 on:** January 28, 2009, 10:39:23 am »

Yeah, it would be a real bummer if you lost the inner coating of styrafoam AND your house in a structure fire. I mean the concrete might catch too and make it a total loss....

THe reality is if your are building with ICF's $$$ and the added cost of sheetrock is not your foremost concern. THey dont give 'em away, but they are user friendly and they sure make an easy heat after. Nice driveby shooting protection to boot if you build your whole house out of them....

Raphael · « **Reply #19 on:** January 29, 2009, 02:37:39 pm »

Quote from: shinnlinger on January 28, 2009, 10:39:23 am

Nice driveby shooting protection to boot if you build your whole house out of them....

I can imagine they're big with the survivalist community for that very reason.
I was amazed at how much kinetic energy just 3.5" of XPS can absorb, especially when it's delivered by an arrow flying at hunting speeds.

jdtuttle · « **Reply #20 on:** January 29, 2009, 07:07:03 pm »

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

Meadows Miller · « **Reply #21 on:** January 29, 2009, 11:52:33 pm »

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 · « **Reply #22 on:** March 12, 2009, 04:22:53 am »

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 · « **Reply #23 on:** March 12, 2009, 08:35:24 am »

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 · « **Reply #24 on:** March 14, 2009, 08:54:02 am »

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 · « **Reply #25 on:** March 14, 2009, 03:58:54 pm »

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 · « **Reply #26 on:** March 15, 2009, 12:35:59 pm »

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 · « **Reply #27 on:** March 15, 2009, 07:03:01 pm »

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 · « **Reply #28 on:** March 15, 2009, 07:50:39 pm »

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 · « **Reply #29 on:** April 05, 2009, 09:27:00 am »

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 · « **Reply #30 on:** April 05, 2009, 09:04:47 pm »

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 · « **Reply #31 on:** April 05, 2009, 10:02:05 pm »

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 · « **Reply #32 on:** April 19, 2009, 09:05:47 am »

Quote from: Alexis on January 25, 2009, 03:09:29 pm

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 · « **Reply #33 on:** April 19, 2009, 09:20:42 am »

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 · « **Reply #34 on:** April 20, 2009, 03:15:02 pm »

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.

News:

Author Topic: permanent wood foundation (Read 4399 times)