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As Mass Timber Takes Off, How Green Is This New Building Material?

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Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#41

Post by pjc50 »

benj111 wrote: post #26
barrkel wrote: post #20

Earlier quoted context omitted.

Sure, but we have concrete buildings still standing from Roman times - most famously, the Pantheon. I grew up in a cottage a couple of hundred years old, with thick walls built from stone and mortar. It's not unusual to live in a house that's over a century old in Europe. I've also lived in a wooden house - more of a three room + toilet chalet, really. Biggest irritations were all the noises from thermal expansion in…

If concrete is similar enough to reinforced concrete. Isn't engineered wood similar enough to normal wood?

Reinforced concrete has different failure modes. The UK built a lot of precast concrete "panel" houses after the war, some of which are disintegrating badly: https://www.peterbarry.co.uk/blog/houses-of-non-traditional-...

Another e.g. concrete disintegrating due to use of mine waste: https://www.theguardian.com/money/2009/nov/29/mundic-test-cr...

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#42

Post by myspy »

proee wrote: post #24

Termites are going to love this ;-) Even with termite treated lumber, they will still need annual inspections to look for damage. If they do find out the structure is laden with termites, it would most likely require a complete evacuation of the building and "tenting" to gas them out - which might be tricky if it's in an urban area. Also, any undetected leaks in the structure could cause slow rotting of the wood.

I have read that termites live in the earth, which means a sufficient foundation should avoid that they can reach the wood?

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#43

Post by myspy »

mjevans wrote: post #3

I would like to know more about the long term stability of the glues involved and how the entire structure as a whole decays / fails over what timeframes under what exposures. Most other building materials in use today, the actual core structural elements, have withstood the test of centuries of use and are well proven and stable technologies.

German houses build of wood are hundreds of years old, so that shouldn't be a problem.

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#44

Post by benj111 »

pjc50 wrote: post #41
benj111 wrote: post #26

Earlier quoted context omitted.

If concrete is similar enough to reinforced concrete. Isn't engineered wood similar enough to normal wood?

Reinforced concrete has different failure modes. The UK built a lot of precast concrete "panel" houses after the war, some of which are disintegrating badly: https://www.peterbarry.co.uk/blog/houses-of-non-traditional-... Another e.g. concrete disintegrating due to use of mine waste: https://www.theguardian.com/money/2009/nov/29/mundic-test-cr...

Different failure modes, different tensile strength, not really the same at all. That was kind of my point :)

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#45

Post by jabl »

chadcmulligan wrote: post #14
mjevans wrote: post #3

I would like to know more about the long term stability of the glues involved and how the entire structure as a whole decays / fails over what timeframes under what exposures. Most other building materials in use today, the actual core structural elements, have withstood the test of centuries of use and are well proven and stable technologies.

I had a home in the 90's that had laminated structural beams, I don't live there any more, but last time I drove past it was still standing. I think its pretty common for housing in Australia, here's some info https://www.thefifthestate.com.au/innovation/materials/expla... Laminated plywood has been used for a long time (70's?), and has been used as cross bracing on timber framed houses. There's also all the sorts of…

The WWII Mosquito was made from plywood. Some of them sent to the tropics had problems with the moisture weakening the glue.

But AFAIK those used different glue than what is used today in plywood production, not to mention 1797.

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#46

Post by masonic »

myspy wrote: post #42
proee wrote: post #24

Termites are going to love this ;-) Even with termite treated lumber, they will still need annual inspections to look for damage. If they do find out the structure is laden with termites, it would most likely require a complete evacuation of the building and "tenting" to gas them out - which might be tricky if it's in an urban area. Also, any undetected leaks in the structure could cause slow rotting of the wood.

I have read that termites live in the earth, which means a sufficient foundation should avoid that they can reach the wood?

Drywood termites fly.

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#48

Post by zihotki »

WalterBright wrote: post #31
proee wrote: post #24

Termites are going to love this ;-) Even with termite treated lumber, they will still need annual inspections to look for damage. If they do find out the structure is laden with termites, it would most likely require a complete evacuation of the building and "tenting" to gas them out - which might be tricky if it's in an urban area. Also, any undetected leaks in the structure could cause slow rotting of the wood.

Concrete rots away if it is not protected properly from water. It soaks up water, the rebar rusts, expands, and splits the concrete.

There are different kinds of concrete and there are some that are specially made to be used in such conditions. Best example will be concrete bridge supports which are constantly in the water.

Re: As Mass Timber Takes Off, How Green Is This New Building Material?

#50

Post by masklinn »

benj111 wrote: post #37
jaggederest wrote: post #21

Earlier quoted context omitted.

https://www.youtube.com/watch?v=4j_UjIshzMc That's literally what it is. You can do it in all sorts of interesting different ways, but the idea is, where with other techniques you'd use e.g. insulation, gypsum wallboard, oriented strand board sheathing or plywood, instead you just... put more wood on it.

There's no mention that this doesn't contain insulation etc, and does explicitly mention that glue is used. I'm not sure you could use that building technique for anything over a few stories.

UBC's Brock Commons opened in 2017 and has 18 stories over 53m. And Mjøsa Tower was just finished (March 2019), also 18 stories but 85m.

They all uses concrete though. Brock has concrete stairwell cores. Mjøsa apparently limited concrete to upper floor decks, for weighting (elevator shafts and stairwells are apparently CLT).

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