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Over the past few years there’s been growing interest in using mass timber for high-rise buildings (now colloquially referred to as “plyscrapers”).
One project that got a lot of attention last year is Brock Commons (student residence) at the University of British Columbia. It is an 18-storey hybrid mass timber tower.
The first and second floor (slab) and the two cores are poured-in-place concrete. After that, the other 16 floors of the tower consist of 5-ply cross laminated timber (CLT) panels and glue laminated timber (glulam) columns running every 10 feet. The roof is steel and metal decking.
Below is a great time lapse video of the building under construction once it had switched over to timber. The wood construction portion started on June 6, 2016 and finished on August 10, 2016. So 2 floors per week.
The video is well-annotated so that you know what week of construction it is, how many wood installers are on-site, which structural members are going in (along with their dimensions), and so on. The CLT panels are only 169mm thick.
Click here if you can’t see the video below.
[youtube https://www.youtube.com/watch?v=GHtdnY_gnmE?rel=0&w=560&h=315]
We tend to think of buildings as being very permanent structures. After all, our cities are filled with buildings that are hundreds of years old. And in some cases, much older.
But the reality is that buildings, just like everything else, depreciate over time. They have life cycles and they need to be regularly maintained and periodically renovated in order for them to survive.
This morning I was reading the blog of Witold Rybczynski, who is an author and architecture professor at the University of Pennsylvania. A few months ago he wrote a post talking about the short life cycle of modernist buildings.
According to a recent colloquium at the Getty Center, the average life span of a conventionally built building (masonry and wood) is about 120 years. But for modernist buildings (reinforced concrete and glass curtain wall) it’s half that: 60 years.
And if you are to consider the typical big box retail store, the life expectancy is probably a third of that – if even that. Usually it is cheaper to just tear down the old box and build a new one when needs change. That’s part of the reason why the leases usually have clauses that try and prevent the retailer from just “going dark” and stopping operation.
So we are literally not building them like we used to. And there’s a lot of debate in architecture and building circles about whether or not this poses a serious problem for cities. It is clear that Witold is unhappy about this shift.
I am a strong believer in heritage preservation. I believe wholeheartedly that cities are far richer with layers upon layers of history. But I also acknowledge that in our world of 6 second Vine videos, we seem to be less worried about whether something will last 60 or 120 years.
Perhaps that’s a problem. Or perhaps the times are just changing.