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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?

#21

Post by jaggederest »

benj111 wrote: post #6
paulsutter wrote: post #2

The correct term is CLT (cross laminated timber). A big chunk of Katerra’s recent big financing is to pay for CLT factories. The cool thing about CLT is that it can be “printed” in arbitrary shapes and sizes in a factory setting and shipped to construction sites for rapid assembly. Structurally it can replace steel/concrete in a certain range of structures. The potential for automation and mass customization is absen…

Came here to say this, I've heard it called 'glue lam' also. Who the hell thought up the mass timber name though?! That just says to me a solid (mass) of unengineered wood.

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.

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

#22

Post by radicalbyte »

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.

Timber at least can last a very long time. There are houses in the UK which dates from the time of Shakespeare which are still standing.

I'm not sure what's worse: a cheap wooden structure which lasts 50-100 years or a strong brick structure which lasts hundreds. Here in Europe we have a large stock of houses from the 1950's which cost 300 EUR a month to heat and cannot be insulated. For a modern passive house costs are closer to 30 EUR a month.

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

#23

Post by radicalbyte »

baybal2 wrote: post #8

Bigger question, how fire inspection ever cleared a wooden highrise?

Probably a lot better than what happens to modern concrete buildings which are then wrapped in plastic:

https://en.wikipedia.org/wiki/Grenfell_Tower_fire

Timber doesn't burn as fast as that, especially in a city as wet as London.

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

#24

Post by proee »

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.

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

#25

Post by ilaksh »

I will just say the obvious thing. I thought we were supposed to be planting more trees. Doesn't cutting more of them down go in the opposite direction?

I like the idea of engineered wood for construction. I am just suspicious that a lot of this hype is coming from the logging industry and the CO2 stuff is just a marketing coup.

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

#26

Post by benj111 »

barrkel wrote: post #20
benj111 wrote: post #7

Earlier quoted context omitted.

Centuries? Reinforced concrete is 150 years old, steel frame construction a little less so.

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?

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

#27

Post by perfunctory »

Quequau wrote: post #17

Do anyone know of any project to genetically engineer trees for producing better timber?

Not genetic engineering but Acetylation technology can increase wood durability [0]. The company mentioned on the wikipedia page is [1]

[0] https://en.wikipedia.org/wiki/Acetylation#Acetylation_of_Woo...

[1] https://www.accsysplc.com/

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

#28

Post by pixl97 »

ilaksh wrote: post #25

I will just say the obvious thing. I thought we were supposed to be planting more trees. Doesn't cutting more of them down go in the opposite direction? I like the idea of engineered wood for construction. I am just suspicious that a lot of this hype is coming from the logging industry and the CO2 stuff is just a marketing coup.

No. In the US the logging industry plants more trees than it cuts down every year. Wood used in building materials sequesters the carbon for as long as the structure stands.

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

#29

Post by harg »

ilaksh wrote: post #25

I will just say the obvious thing. I thought we were supposed to be planting more trees. Doesn't cutting more of them down go in the opposite direction? I like the idea of engineered wood for construction. I am just suspicious that a lot of this hype is coming from the logging industry and the CO2 stuff is just a marketing coup.

I guess the argument goes that if demand for timber increases more forests will be planted.

Sustainable forestry generally involves replanting the trees you cut down, often several times over. Of course, as the article states it's pretty important that the timber comes from sustainable sources if it's to actually have a chance of benefitting the environment.

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

#30

Post by agumonkey »

ilaksh wrote: post #25

I will just say the obvious thing. I thought we were supposed to be planting more trees. Doesn't cutting more of them down go in the opposite direction? I like the idea of engineered wood for construction. I am just suspicious that a lot of this hype is coming from the logging industry and the CO2 stuff is just a marketing coup.

planting / cutting flow would displace cement which may still be a net positive in terms of CO2 emissions
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