New wood technology may offer hope for struggling timber industry

Japan needs something like this to get rid of the millions of hectares of unsightly cypress and cedar plantations that blight the countryside and have replaced the beautiful mixed native forests (The plantations are so depressing I find it distressing to visit the countryside). As well as being ugly, these monoculture plantations are almost biologically dead, do not hold water and soil well and cause widespread allergic reactions. If they need to spend taxpayers' money on anything, rather than concreting every last stream or rivulet, why not make use of these plantations and replant mixed forests?

Moonraker - Spot on!

This is just really thick plywood (and I love plywood - so useful for everything!) - but Google some architectural examples. It is quite amazing.

What they aren't telling you is that the glue holding the wood bits together is highly flammable! So much so that homes made from such manufactured materials burn up in 5 minutes, compared to homes built of solid wood boards that take 20 minutes. That means people on the second floor may not have time to escape before the heated glues explode in a massive fireball, so people on higher stories would certainly be living in a potential fire death trap! The explosive nature of the glues is also putting the lives of firefighters at high risk. That's why I refused to use any such materials when building my house, in which the framing is all made from solid construction grade wood boards.

Perhaps the boards can be screwed together. what an idea!

What they aren't telling you is that the glue holding the wood bits together is highly flammable! So much so that homes made from such manufactured materials burn up in 5 minutes

That's not my understanding. I've read that CLT can be built to achieve the various fire-resistance specs. Below is a piece from one manufacturer's website. They could be lying, but other sites seem to back this up.

Unlike traditional timber frame construction, CLT can be designed to achieve a fire rating of 30, 60 or 90 minutes. In a fire, a charred layer forms around an un-destroyed core which retains its load bearing capacity, thus reducing the entry of oxygen and heat from outside which delays significantly the further spread of flame. Cross laminated timbers inherent fire resistance makes it the only structural timber solution to comply with Fire Resistance REI classes: REI30, REI60, REI90 and REI120 (loadbearing capacity, integrity and insulation) and performance requirements without the need for add-ons, building ups or adaptations.

RIddle in Douglas is a beautiful part of Oregon. Good luck to them all!

The wood building at the University of British Columbia, Canada is 18 storeys. There is a timeline of the construction on a local BC news site here. http://globalnews.ca/news/2943184/worlds-tallest-wood-building-completed-at-ubc/

Jim Poushinsky,

What they aren't telling you is that the glue holding the wood bits together is highly flammable!

It would appear that your fears (and claims) are unfounded. On the contrary, a variety of sources have reported that CLT woods can actually be even more fire resistant than traditional wood building materials, and behave more closely to concrete in how they react to fires.

From the website Building Design + Construction:

Like using a few 12-inch-diameter logs to start a camp fire, [CLT] mass timber does not catch fire easily. In fact, CLT acts more like concrete. Mass timber is not conventional so it is very hard to light, and once it is lit, it wants to put itself out (see US CLT Handbook Chapter 8, p. 2).

According to the website, Fireengineering.com:

CLT panels are promoted as having excellent fire resistance, comparable to that of non-combustible materials and to heavy timber (Type IV) construction, due to the ability of thick wood assemblies to char slowly at a predictable rate while maintaining most of their strength during the exposure. After testing CLT panels to the standard fire resistance test (CAN/ULC S101 (Canada), ASTM E119 (USA), and ISO 834 in other countries), manufacturers propose that a five-layer CLT floor panel can receive a 1.5-hour rating; and a three-layer wall panel can receive a 45-minute rating.

According to the American Wood Council:

AWC conducted a successful ASTM E119 fire resistance test on a CLT wall at NGC Testing Services in Buffalo,NY . . . The 10×10 foot test specimen lasted three hours, five minutes, and 57 seconds (03:05:57)—well beyond the two- hour goal.

I could cite at least a half-dozen other sources that say pretty much the same thing, namely that CLT actually provides better fire resistance than traditional wood building materials.