Wood Foundations

[rwand1]

Vern

Very interesting. Of course the house not worth anything, but there remains the value of the land, not that that helps.

How come concrete blocks are not permitted?

[Jason A. Sieg, CMI]

What are you referring to when you say "PTW or PWT"???

"PWF" is Permanent Wood Foundation.

I just want to make sure I know what your talking about.

[cbuell]

Originally Posted by vmitchinson

Fortunately I do not get very many wood foundations in this area. The ones I have inspected all have had water infiltration problems with severe mould problems. (I have never seen water infiltration and mould problems in concrete foundation systems ) One in puctular was condemned by the health board and ordered the occupants to vacate immediately. The family was forbidden to take anything with them. They are now living in a motel. This house will be burned as the toxic moulds are too severe for anyone to enter safely and fix it. It was built in 1976.
The pressure treated wood foundation association has not answered any of my queries. They have not even acknowledged receiving my inquiries.
The city of Edmonton does not allow concrete block foundations and I wish they would add PTW foundations to the unacceptable list.
A number of posts talk about how wonderful PWT's are but my experience says otherwise. All foundation systems can experiece problems due to fauty installation, site conditions etc. Properly installed PWF's can be just as good---and sometimes better than concrete foundations----particularly in relation to concrete blocks. These systems are "designed/engineered" to never "see" water. They were originally designed by Weyerhauser for structures in the artic because concrete foundations were not as resilant in perma-frost conditions. Any bowing or collapsing of walls would be the result of faulty design/installation as with any foundation.

The manufacturers of this product have not replied to my requests for information where as the portland concrete association has always provided all the information I have ever asked for.

On one PWT foundation the bank would only provide a 15 year mortgage because the PWT was guaranteed for 40 years and was 25 years old.

For more information on a previous discussion go to
http://www.nachi.org/forum/showthrea...od+foundations

I think there is still info on the Weyerhauser site.

[rwand1]

Jason asked..

What are you referring to when you say "PTW or PWT"???

"PWF" is Permanent Wood Foundation.

I just want to make sure I know what your talking about.

Same thing. Pressure Treated Wood Foundation.

Cheers,

[wforsyth]

I think that the longevity of wood can be shown in the 100-200 year old or more log homes and barns that one can find standing still today. Often times with gaps where the chinking has long gone away.
In Louisiana one can find beams from Cypress trees laying in the water where they have been for decades, and still recover the wood and use it in new construction of log homes.

[Claude Lawrenson]

Good info & more links

http://www.oaa.on.ca/client/oaa/OAAH...Document&PFV=1

[Vern Mitchinson]

Originally Posted by rwand1

Vern

How come concrete blocks are not permitted?

I'm not sure why they are not acceptable.
They were used back in the 20's and thirties and the few I've inspected are caving in horizontally about 4' up from the floor.

Just did a new house under construction this PM What a mess. The footing had a 1/2 inch crack in the corner and the crack ran 3-4 feet up the wall. There was a diagonal crack 1/2" wide from the window down to the corner where another crack ran up the Wall from the footing. An inside corner has a crack 3/4" wide. I suspect that there is no re bar in the walls. The plans called for two #10 re-bars top and bottom. This foundation was poured last fall.
Yes as stated above all foundations can be a problem if not done right.
All the walls are out of plumb, floors not level and roof trusses not resting on the walls. The whole house is moving and twisting.

Where's Mike Holmes when you need him.

[Vern Mitchinson]

Originally Posted by wforsyth

I think that the longevity of wood can be shown in the 100-200 year old or more log homes and barns that one can find standing still today. Often times with gaps where the chinking has long gone away.
In Louisiana one can find beams from Cypress trees laying in the water where they have been for decades, and still recover the wood and use it in new construction of log homes.

Wood above grade is a whole different thing then a wood foundation.
In this part of the world the soil is clay and is always wet. So foundations have to be 100% water proof. Concrete works well because it's solid but wood foundations are hollow and any water that gets in is trapped and the dark damp warm cavities are perfect for mould and boy does it grow.
Mould feeds on the organic wood so not only do you have a health problem but the wood is being consumed by the mould. It's called rot.
The next time you are at the lake take a look at the wood piers. The dry wood above the water is OK. The wood that is always under water is OK. The part that is in the wet dry zone is where the rot takes place.

[lewens]

Common Vern,
I have seen and inspected many homes with mud sills that have lasted well over 100 years. The cause of wood rot is moisture and if you keep the moisture away from the wood, no rot.
Larry

[Jason A. Sieg, CMI]

Originally Posted by vmitchinson

Wood above grade is a whole different thing then a wood foundation.
In this part of the world the soil is clay and is always wet. So foundations have to be 100% water proof. Concrete works well because it's solid but wood foundations are hollow and any water that gets in is trapped and the dark damp warm cavities are perfect for mould and boy does it grow.

This is where builders that are not familiar with PWF make their first and most problematic mistake! PWF ARE NOT a sealed system designed to keep water out! PWF IS designed to direct water away from the foundation! They also should never have drain tile installed... Drain Tile under a PWF will guarantee the foundation to fail! Backfill is mostly peagravel.

This is a system where there are no shortcuts. Also the builder may never think that he/she is making the foundation better by adding sealent somewhere the plans don't indicate sealant to be! That will guarantee the foundation to fail also! The plans MUST be followed to the letter!

[George A. H. Luck]

Vern;
Could it be that block foundations are failing because of the much deeper frost way up there north of the arctic circle ? a friend of mine lived in Edmonton and said that the frost often reaches 4-5 feet into the ground. If true this would put additional stresses on the walls. certainly more so than found down here in the banana belt.

[wforsyth]

Originally Posted by lewens

Common Vern,
I have seen and inspected many homes with mud sills that have lasted well over 100 years. The cause of wood rot is moisture and if you keep the moisture away from the wood, no rot.
Larry

Exactly.

[rwand1]

It depends on the spieces of wood used in mud sills, how close it is to grade or below grade, and weather, such as leeward side where snow builds up and melts in spring. I have seen lots of mud sills in century plus homes that have rotted out. Grading issues, and downspout water management, or lack of gutters all play a role in longevity.

[Vern Mitchinson]

Originally Posted by jsieg

PWF IS designed to direct water away from the foundation!

Please explain what you mean. How do you direct water away from the foundation?

They also should never have drain tile installed... Drain Tile under a PWF will guarantee the foundation to fail! Backfill is mostly peagravel.

Why will the tile cause failure?

Back in the 60's the specs call for water proofing bituman to be painted on exterior of foundation. Later they called for 6 mill poly on the exterior.
Is this what you mean?

[Vern Mitchinson]

Originally Posted by gluck

Vern;
Could it be that block foundations are failing because of the much deeper frost way up there north of the arctic circle ? a friend of mine lived in Edmonton and said that the frost often reaches 4-5 feet into the ground. If true this would put additional stresses on the walls. certainly more so than found down here in the banana belt.

The code calls for foundations to be a minimum of 4' 6" below grade.
Frost penetration depends on the amount of snow cover. Frost in the street can go 8 to 10 feet deep.

</IMG>