Wooden Skyscrapers: Bad idea or environmentally smart?

Supposedly modern adhesives can be used to create laminated panels with the strength and durability of concrete and steel. Plus, according to the article, while the manufacture of concrete and steel for a 20 story building can release 1,200 tons of CO2, the same building made of wood would sequester 3,100 tons of CO2.

This all sounds fantastic, if true. However the article then talks about how harvesting timber, and even clear cutting certain areas, makes for healthier forests and can prevent forest fires or at least reduce their spread. This part sounds to me like something right out of the lumber industries PR book, making me wonder if the whole article isn’t industry PR.

So does any of this make sense? Can wooden skyscrapers be as strong as concrete and steel? What about building fires (the article claims that the massive panels would only scorch)? Would the glue age and become unreliable? What about termites?

I know, from talking to my parents, that maintaining a regular wood house can be quite a chore. I would have to imagine that the maintenance costs for a larger wood building will be pretty significant.

Now, they might have some advantages over regular wood buildings, in that there’s so many chemicals permeating the wood that decay, insect infestation, etc. will be significantly decreased compared to a regular wood house, but it would still be a larger issue than with a steel and concrete building.

And then there’s the issue that this is a new style of construction. Skyscrapers - as I understand it - are rather difficult to engineer. There’s a lot of issues around pressurizing them appropriately, controlling the internal temperature appropriately, etc. So far, every building which has tried to do something new and interesting that I’ve heard of, has ended up having some significant issues for the people who actually had to work in that building. And this seems like a much more significant overhaul of the structure than anything I’ve ever heard of. I think it’s a given that the first generation or two will be rather uncomfortable on the inside.

But, fundamentally, they know the material qualities and can engineer the overall structure based on that using simulation software and math, so I wouldn’t be worried about the building collapsing. They probably have a decent idea of how fire works, so that might not end up being too big an issue (though…I’m not sure I fully trust the optimism on that front). So, mostly I think they’ll just run into issues with the comfort and maintenance of the buildings.

One of the head-scratchers is that when wood catches fire, the char doesn’t make the fire go out … it keeps burning … worsterest is the glue burning producing toxic smoke. OTOP even steel building get fire-retardant sprayed over everything, so the fire hazard may be a wash either way.

The wood is already ‘sequestered’ whether it stands in the forest or in heavy-carbon-belching-during-manufacture structural building elements. The difference is that living trees will continue to ‘sequester’ carbon whereas dead buildings do not.

Is this building in BC able to withstand the expected regional earthquake? I’m not sure a steel and concrete building could withstand a 9.0+ M[sub]w[/sub] trembler, and even if they do, everything else in the area is coming down.

I guess we’ll know in 50 years if it’s a good idea or not, hope the glue will last that long.

I wonder about the effect of fire on the glues. I suppose that’s all been tested.

What about earthquakes? What about plane crashes? What about terrorist lumberjacks with big saws?

ETA: **watchwolf49 ** ninjaed me on some of my points!

The claims in the article seem exaggerated, but that doesn’t mean the principle is invalid. Steel and concrete aren’t immune to the effects of fire either. We don’t really know how long the new composite materials last but we can probably estimate accurately enough that certain construction will last more than 100 years. Wood will insulate better than concrete and steel, and properly designed it should be easier to make repairs and modifications to wood structures.

This is really just using wood as both fiber and core in a composite material held together by glue, and treated to prevent rot and absorption of water. It sounds like a pretty good approach, if it’s cost effective someone will try it.

It doesn’t actually seem that far-fetched. They’ve been able to build very tall structures out of wood like radio towers and railroad trestles for a long time.

Are you suggesting that certain adhesives are actually much older than commonly thought?

No. What led you to that?

Supposedly modern adhesives can be used to create laminated panels …”

Why would you think they are not modern?

I suppose you meant this:

“Supposedly, modern adhesives can be used to create laminated panels…”

Ah, the comma. :smack:
A typo.

If left alone, the tree will die, rot and release most of its carbon - an established mature forest is pretty much carbon neutral, unless it’s laying down material that is prevented from rotting (e.g. in a swamp or some such).

Removing the tree from the forest and using the wood for any long term purpose sequesters the carbon for the lifetime of that usage, and creates a space for another tree to grow and sequester some more (and often faster due to the rapid growth phase of sapling trees).

People have an old fashioned view of what a wood building is. Modern wood construction is advancing rapidly and wood is now an incredible material in all sorts of ways that makes it an interesting building material.

That being said, the environmental advantages listed in the article are pretty trivial. Carbon offsets are priced at around $10 a ton so an entire skyscraper’s worth of savings is only $40K which is a rounding error. Wood skyscrapers should be built if and when they are genuinely better, not because of some insignificant environmental benefit.

I have a few points to add:
[li]If one call this material “wood”, you should do the same for plywood, paper and particleboard. It is an engineered material from cellulose.[/li][li]20 story building is a tall building, but not a skyscraper.[/li][li]It is true that large timbers will not burn completely right-away, but only char on the outside. However, this still reduces the timber’s strength by a half. This is no issue for a residential house, where the structural elements are only loaded to a fraction of their strength. But it is enough to bring down a tall building.[/li][li]And effects of fire on solid timbers and laminated materials are very different anyway. What the article says applies to solid timbers only. Laminated materials burn differently. Fire burns preferentially along the boundaries, disintegrating the material.[/li][/ol]

How long is this wood/glue composite material going to last under load bearing stress?

  1. The steel that makes up the structure of a skyscraper doesn’t insulate it. It’s a skeleton. Why would you care how it insulates?

  2. What makes you think wood’s easier to fix? For that matter, how often does a steel structure need to be “fixed”? Barring a catastrophic accident, almost never; they are amazingly durable.

Insulation has to be added to steel buildings. The insulating property of wood are just another advantage. I’m not saying wood construction of this type is superior to steel and concrete, insulation is just one of the factors to consider in the analysis.

Wood is easier to fix. It is not as hard as steel or concrete and can be more easily repaired, patched, and replaced because it is a more workable material. And steel and concrete structures do need occasional repairs. Again, I’m not advocating that wood is better than steel, these are things to consider in making such a decision.

I’m not sure that all the carbon in a dead tree is released as CO[sub]2[/sub] in a fire-less situation. Plenty of microbes are available to keep the carbon in the biology. As far as how long the tree lives is a matter of locale, for Douglas Fir “ages of 650 years are fairly common in western Washington and British Columbia” {Cite}. I don’t think we’ll find very many buildings made of wood that are that old.

Also, the article in the OP specifically states that they are harvesting the young small trees for grinding, the older bigger trees are still to be used for dimensional lumber. But that’s just one species of tree, my understanding is that these “engineered” products can use most any type of tree … and I’ve heard there’s research beginning that would use marijuana.

If we built a thousand of these buildings per year, that only locks up 4,000 metric tons of CO[sub]2[/sub]. A very small percentage of the ten’s of gigatons we release burning fossil fuels.

I don’t disagree that building wooden skyscrapers is an impotent way to sequester carbon.

But in regards trees and forests: if the biomass of the forest is getting bigger (including if the dead bits of it such as peat layers are getting bigger), then it’s a net carbon sink - otherwise, it’s breaking even.
In general, forests don’t lay down dead carbon permanently any more*, because of the diversity of organisms that consume the dead material and release CO2 or methane in the process.

(*not like back in the good old days of the carboniferous period, when fungi were scarcer or nonexistent)

This is a fair point. I personally would draw the line where the original grown grain structure of the wood is lost or not relevant to structural strength - so solid timber is wood; ply and maybe OSB are engineered wood; particle board and paper are new products derived from wood.

The effect of fire on the non-wood-derived components of the material is also a factor to be considered. An engineered wood product strong and durable enough to build tall buildings is almost inevitably going to contain a significant amount of synthetic resins - which behave differently to wood at high temperatures, adding to the difference from solid timber - of course, lots of study already exists on the effect of fire on these materials

Sounds like ply in the sky to me.