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.

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Author Topic: permanent wood foundation (Read 4399 times)