Thermally Treated Wood

[awdriven]

Has anyone worked with thermally modified wood?  I'm familiar with kiln drying, which removes excess moisture and kills borers. This is a different process.

It's apparently been used in europe for about 10 years, but is not very widely used in the US. I just became aware of it while I was doing some research for a storage shed I'd like to build.

Most of what I find is marketing materials, so only good news, no real-world commentary - or negatives.

My understanding of the process - the wood is heated in a kiln to about 400 degrees for about 2 hours. (Hotter and longer than traditional kilning)

This cooking process changes the appearance, the physical structure, and the chemical makeup of the wood. Wood treated this way:

    * Weighs less than the same untreated wood
    * Has color uniformly darker throughout the piece
    * Increases durability significantly
    * Reduces water absorption by up to 80%
    * Increases hardness by as much as 50%
    * Significantly reduces tangential and radial swelling
    * Remarkably improves machinability

As a result, you see woods like thermally treated poplar and pine being sold as outdoor-rated siding, decking, etc.

Anyone have some experience with this kind of material?

 

[Eli]

There was a house in a recent issue of 'Dwell' that was clad with recycled wood that had been treated using this process. They apparently used no other exterior treatment for the wood.

 

[GruntSgt]

I've been reading and researching as much as I can find and have found you find more "written word" than the actual product. I ask the local lumber yards about it and all I get is "HUH! Say What?. I'd like to score some and give it a weather test here in Montana. If it's as good as I've been reading I would use it to finish our deck. Ipe and WR Cedar are [eek]. Fine Homebuilding has had an article or two on it, you might check their website.
Dan

 

[woodguy7]

I have used it on the new Tesco supermarket a few years ago.  Seems kinda weird, really light in weight.  There was no finish applied to it but it has only on about 3 years so hard to say.  Still looks good, weathered in for colour.  I am sure others have used it a longer time ago.

Woodguy.

 

[CDM]

There is a wealth of interesting material in the sidebar hyperlinks at the Westwood Corporation web site.  I suspect you won't find woodworker forum comments about it mainly because it doesn't seem to be all that widely available.

I think I'm going to try to lay hands on some in the near future.  I like the notion of red oak as a relatively common North American hardwood becoming much more suitable for furniture building due to improved dimensional stability and also darker wood without the mess and fumes of stains.  It looks like from Chicagoland there's a warehouse source up in Milwaukee, or else I'll be in for a direct-mail experience from further afield.

 

[jakiiski]

Please note that some people find the smell of the wood a turn-off (smoke). Heat treatmet also decreases the structural strength of the wood -> i.e. you need thicker/taller wood for the same load compared to non-heat treated.  Planing heat treated wood (at least birch) is also very, very difficult... It tears very easily.

Some of the outdoor experiences of the wood have not been that favorable, at least with the 1st batches here in Finland - it should have a roof on top of it.

 

[CDM]

Moi! Harrastan puuntyöstöön.  Puhun suomea vähän suomea.  Haluan oppia puhumaan suomea paremmin.

Okay, that's partly from Google translate, and partly from my long-forgotten copy of "Finnish: A Complete Course for Beginners" which I just went and found in a corner bookshelf.  I lived in Espoo for a year as a student a decade ago.  At the time I was studying mobile phone technology but was not yet interested in woodworking.

If it's alright with you, I'm going to brush up on my language skills and occasionally give you a comment or a question in Finnish.

 

[BTDT]

Is this how they create caramel/coffee roasted maple?

Planing heat treated wood (at least birch) is also very, very difficult... It tears very easily.

I pretty much have that experience regular Birch!