Wood foundation?

Anyone ever seen one of these? No concrete, no cement block, but pressure treated lumber! Even our real estate agent said she has heard of it but never seen it. I would worry about the life span of the wood compared to block. What do you people think? This is a brand new home.

 

Several years ago they started doing this type of construction, it is based on the same principle of using 24"o.c. (inches on center). Someone came up with the bright idea that more trees would be saved if you used 24"o.c. than 16"o.c. Then they came up with the bright idea of using pressure treated wood without a foundation, like your house. This was done to bring down the cost of the house, which it did. This did not go over too well with buyers and construction of this type stopped. I guess someone is trying to bring it back.

 

Well, we didn't buy that house (high tax area). But, that is prob. why it is still not sold after 8 months. I talked to some carpenters buddies--they said it makes for a real nice foundation if done properly, and actually costs more to build than block or poured concrete. I agree with the 24"oc and 16"oc, most newer houses I have looked at are 24"oc, my old house 1955, was all 16"oc. I was told years ago not to but 24"oc, but unless you build it yourself--your gonna get 24"oc! Way I figure--it meets code--and if something happens--that is why I carry insurance!

 

Per the "Mod 24" system, it worked, but wasn't nearly as cost effective for interior finishing systems. It required heavier systems, i.e. 5/8" drywall vs. 1/2", etc.

I've built Permanent Wood Basement & Foundations on numerous projects, both new, under existing, etc. The home owners of these basements, especially after having lived with a concrete basement enthusiastically prefer the wood. These people brag about their basements. One I know of had his as an addition to a concrete basement in the early 60's, and has stated many times over the years, that he wished it was ALL wood.

They are both warmer & dryer, pryor to but allowing for batt or blown insulation, no requirement for furring out the walls for finishing, electrical or plumbing run any where you wish, etc. No cracks in the walls, and if there is any settling, it all moves uniformly.

The only drawbacks I've ever heard of are from those who didn't use the proper required materials and fasteners to complete the project(s). 16" o.c. is the widest stud placement allowed in an of the designs. Properly constructed, PWFs have lasted for over 100 years now.

Per the COST, for a normal 4 corner rectangle, there isn't much cost savings. However, with additional corners, etc., or placing under an existing structure, it has considerable cost savings.

 

Just got back, most of the newer construction we have looked at are 16"oc walls and are usually constructed of 2x6. What I see 24"oc are the roof trusses, and the osb board looks like 5/8" (just seems alittle weak considering the snow we can get here), course I suppose it depends on the pitch of the roof also(just an armchair builder here!). In fact the house I decided to buy was built in '97 and it is exactly that way, with a cmu foundation of course. A friend of mine has a garage with 24"oc roof and he is having problems with sagging between trusses--not sure of the thickness of his osb.

 

redneck,

Just a word, the sagging may be related to not using H clips and this has been a problem here with some builders, if you call them that, not doing things right. 7/16" is fine for 16" O.C. trusses but bumping it up to 1/2" with H clips for 24" O.C. is better although 7/16" is acceptable on 24" O.C.. Other factors can play into sagging sheathing, pitch of roof, ventilation, minimum material used, etc. The one issue that i ahve been seeing is lack of ventilation as it may cause condensation under the sheathing which leads to some premature deterioation/weakening.

The other issue is that my Uncle was Contractor and most of his homes in Minnesota were wood foundations. My Aunt has lived in her home for since 1973 and has had no problems at all with the wood foundation. As they always say, if you start with a firm foundation, you can only go up! (nice slogan)

Good Luck!

 

I build wood foundations all the time. It is the preferred foundation by knowledgable people. In most cases, the houses require 2x8 Foundation Treated Lumber (different then pressure treated) 16" on center. If it is a 2 story house they are put 12" on center. Many other factors go into these walls, but they will last longer then concrete or block. Usually in the 75 year to 100 year plan. They are warmer, and if done right, do not leak. I have one of these jobs going all the time. As far as the roof materials asked about. I always put trusses 24" on center with 5/8" osb with clips, and staggered joints, nailed every 6" throughout the field. I have never had a saggy roof in 30 years. Lucky I guess.