
The Case for Making Cities Out of Wood - cjg
http://nautil.us/blog/-the-case-for-making-cities-out-of-wood
======
netcan
For the people saying "fire!"...

Wood went out of fashion because of urban fires, resource (natural forest)
depletion and long term maintenance (rot, termites..) issues.

Modern engineered timber (according to proponents) solves these problems. It's
engineered from renewable crops of fast growing timber, is resistant to fire
and pests... Proponents claim it is now suitable for skyscrapers but certainly
for 5-15 story urban residential buildings.

Imo.. what is missing are clear advantages, a reason to bother. I don't think
there's much cost advantage at this point. Weight savings.. maybe there are
some applications where this is important. Generally, it's a bit of a solution
searching for a problem.

~~~
Tharkun
> Imo.. what is missing are clear advantages, a reason to bother.

There are quite a few actual advantages. Speed of construction is one. The
ability to prefabricate large elements (like entire walls) off site is
another. In some areas of the world there's a lot of cheap excess timber after
some kind of pest (I'm thinking a beetle?) killed entire forests. It insulates
really well out of the box, especially when it comes to noise insulation.
Wooden buildings are more earthquake resistant than stone/concrete.

There's also quite a number of disadvantages with concrete. Lack of sand.
Implication climate change. Requires rebar reinforcements which ups the price
and turns the whole thing into a giant radiator.

CLT is a pretty awesome building material, really.

~~~
escape_goat
> In some areas of the world there's a lot of cheap excess timber after some
> kind of pest (I'm thinking a beetle?) killed entire forests.

Dead wood isn't even useful as firewood. You can't just pick dead trees up off
the forest floor and saw them up into lumber. Even if you could, no government
would let you transport that timber out of the immediate vicinity in which it
was found, due to the aforementioned pest.

Perhaps there is a surplus of cheap excess timber in some areas of the world,
but there isn't much chance of that having anything to do with any kind of
pest.

~~~
hutzlibu
"Dead wood isn't even useful as firewood"

Sure it is. You mean degraded, rotten dead wood .. but "fresh" dead wood is
firewood.

~~~
escape_goat
That's a fair distinction to make.

When a tree is killed by a pest such as the emerald ash borer, it dies because
the boreholes allow fungus and bacteria into the core of the tree. By the time
the tree is visibly dead, very little of the wood is 'fresh'. It cannot be
used as lumber, or even firewood.

------
tomrod
> A recent advance in wood technology should interest the neighborhood’s
> developers: Teng Li, a University of Maryland mechanical engineer, created
> with his colleagues wood that’s as “strong as steel, but six times lighter,”
> he said. Liangbing Hu, Li’s co-author on the study, added, “This kind of
> wood could be used in cars, airplanes, buildings—any application where steel
> is used.” Making it is just a two-step process. The scientists first boiled
> natural wood in a mixture of sodium hydroxide and sodium sulfite, to remove
> some of the lignin and hemicellulose, substances contained in the walls of
> wood cells (the former retard parasite and bacterial attacks, the latter
> cover and bind fibers). Then they put the wood in a hot press, which leads,
> as they say in the paper, “to the total collapse of cell walls and the
> complete densification of the natural wood with highly aligned cellulose
> nanofibres.” The result, they conclude, is a “low-cost, high-performance,
> lightweight alternative” to “most structural metals and alloys.”

If this decreases the burn rate, as other commenters have pointed out, and the
input energy is manageable, then this has a chance. Cool!

~~~
perl4ever
The obvious question, to me, is whether this process can be used to produce a
uniform enough product to be highly reliable.

------
chriswarbo
> Teng Li, a University of Maryland mechanical engineer, created with his
> colleagues wood that’s as “strong as steel, but six times lighter,” he said

Phrases like this make me uneasy. "Strength", especially when used informally
like this, is quite ambiguous (e.g. there's a reason we don't make buildings
out of spider silk).

Overall it's quite an uplifting piece though, and I would certainly like to
see such a revival.

------
vinayms
Even if the technology is perfected and proven superior on several counts, the
adoption has to overcome the psychological barrier. The places that don't have
a culture of wooden buildings, especially the floor, will need some
convincing.

As an Indian, I don't encounter wooden floor often. Modern buildings are all
brick and reinforced concrete, and old temples are stone mostly. Any wooden
floor one might come across are just wood panels installed on concrete floor.
Nearly two decades back, the city library (Seshadri library, Bengaluru) was
renovated, and as a part of it the shelves were raised and a wooden corridor
was installed to enable access to higher shelves; its a tall building with a
dome and a large hall under it, your typical library. Needless to say, I was
quite apprehensive to walk on it, so were most people there. Apart from that,
the only experience I have is standing on my desk to change the bulb. The desk
is quite sturdy - the bulkier carpenter stood on it to demonstrate - but I
just can't trust it the same way I trust concrete floor. When on a wooden
surface, I step softly, hoping to make myself lighter, just in case, though I
know its nonsense.

~~~
crooked-v
With the mention of temples, it's actually pretty common for historical
temples, churches, and castles to have wooden rooms for anything past the
ground floor, since it was much, much easier to build a few main structural
supports out of stone and then fill in the rest with wood later.

Of course, I'm a little biased on the subject, living in a 100-year-old all-
wooden building (you can see the huge beams resting on the foundation in the
basement) that I chose for earthquake resistance. I'm actually a lot more
comfortable knowing that the whole building can sway while all the parts stay
attached, compared to the many old brick buildings around here that will
literally fall apart if an earthquake happens.

------
pseudolus
There are actually plans to build a 350 meter (approx. 1050 foot) skyscraper
in Japan. [https://www.dezeen.com/2018/02/19/sumitomo-
forestry-w350-wor...](https://www.dezeen.com/2018/02/19/sumitomo-
forestry-w350-worlds-tallest-wooden-skyscraper-conceptual-architecture-tokyo-
japan/)

For those interested in more "concrete" expressions of the existing
capabilities of timber based construction an 18 story dormitory was assembled
in 70 days at the University of British Columbia.

[https://news.ubc.ca/2016/09/15/structure-of-ubcs-tall-
wood-b...](https://news.ubc.ca/2016/09/15/structure-of-ubcs-tall-wood-
building-now-complete/)

Here's a time-lapse:
[https://www.youtube.com/watch?v=GHtdnY_gnmE](https://www.youtube.com/watch?v=GHtdnY_gnmE)

------
lifeisstillgood
If you can extrude or shape the densified wood, into something "branch-like"
but at steel like strength then you open up new building opportunities - our
cities are dominated by straight lines, for good reasons, but branchlike
handrails, footpaths and arches open up a lot of possibilities for good
architects to chnage the look of a city beyond the mere material it is made of

~~~
ctack
There is a compression step in wood preparation life cycle. You could replace
this step with shaped moulds to create these features. Or maybe it's cheaper
and easier to 3D route out of bigger masses.

~~~
lifeisstillgood
just wondering how much pressure it takes to compress wood to destroy the
cellular structure. One might suspect more than enough to crack a mould that
had lovely curvy shapes in it ...

------
chasedehan
The question I have about all of this is the environmental impact of the
"densification of wood." They cite it being similar to paper manufacturing,
which is really energy intensive and is a horribly polluting industry.

I don't have any info on the above, but it is something I wonder about.

------
m0llusk
First of all, what they are talking about is more like paper made out of wood
since the fibers are treated extensively and then formed. Secondly, large and
spreading structure fires which have such a devastating history have been
essentially eliminated by use of sprinkler systems.

------
specialist
I'm day dreaming about 'aktivhaus' (sp?) style residential in the desert.

What would that look like?

My starting notion is a three level structure. Bottom is carport, patio,
storage. Middle would be kitchen, baths, common areas, study. Upper would be
bedroom(s). Maybe a roof top deck.

South wall would have horizontal solar louvres. Kinda like the Burr library in
downtown Phoenix.

Roof top solar something. But I'd still want to be able to look up at the
stars.

Grey water system of some sort. So the ground level would have a cistern of
some sort.

Is wood a viable option for the desert? I know zilch about thermal loads,
insulation, etc. If so, how much wood?

------
golergka
Three out of three top comments here are about fires - an issue the article
specifically talks about.

How about reading the whole piece instead of just a headline?

~~~
xigency
> He wants to do many more experiments because it’s still not clear how, in
> mass timber buildings, to get compartment fires to reliably burn out on
> their own, a “cornerstone of fire safety engineering design,” he writes.

In this context, the article's later comparison of this wood to concrete seems
exaggerated.

------
avoidwork
Some cities were wood, and they burned. My concrete condo is in the burn path
of the 'great Ottawa fire'. Wikipedia doesn't have enough pictures, worth
googling.

[https://en.wikipedia.org/wiki/1900_Hull–Ottawa_fire](https://en.wikipedia.org/wiki/1900_Hull–Ottawa_fire)

~~~
bryanrasmussen
I'm wondering if 'total collapse of cell walls and the complete densification
of the natural wood with highly aligned cellulose nanofibres.' means that
stuff isn't going to burn until you get temperatures where steel melts anyway?

~~~
farrisbris
It would seem so. from the article:

> Massive wood walls and structural beams and columns comprised of engineered
> panels have demonstrated fire performance equal to concrete and, in some
> cases, superior to steel

~~~
singularity2001
one big difference seems to be that once the critical point is reached, even
if the threshold very high, the wood contributes to the fire and nourishes it,
unlike concrete or steal. a skyscraper with proper sprinkling should be fine.

------
bl4ckm0r3
Emperor Nero likes this element!

------
fredley
The case against:

[https://en.wikipedia.org/wiki/List_of_town_and_city_fires](https://en.wikipedia.org/wiki/List_of_town_and_city_fires)

~~~
xigency
I think of Chicago first. The wood city that burned and led to the invention
of 'skyscrapers'.

~~~
nervousvarun
The focus of this article is innovation in this space.

What happened in Ottawa or Chicago or Tokyo is relevant in a historical sense
but this is about recent innovations that make wood viable (both from a
safety/fire-resistant perspective and economical).

~~~
tyu1000
I think we all know this, but this article was less-than-convincing and
nothing has been deployed at scale yet.

