Because we are not called TreeHugger for nothing.
Looking back on 2017 it is hard to know where to start, there was so much happening. It's the year that wood construction really went mainstream, everywhere. We are not even going to discuss the fantasy projects, just the real stuff being built by real architects. Because we are past gawking at models and renderings, things are getting built!
He envisions a future where instead of chopping trees into lumber which is then glued or nailed into mass timber, we 3D print it from wood fiber, in the shapes and forms that are most efficient structurally. Then all of the wood fiber will be used and there will be no waste, either on the forest floor or in the building itself. We will not only build using trees, but will build like a tree.More: Michael Green goes way beyond tall wood
We playfully call these transformer buildings today, but in fact they have a history that goes back hundreds of years. Aki Hamada has taken a prosaic program and turned it into an architectural gem, a wooden wonder.More: Multipurpose building is a flexible wooden wonder
...the reasons for using CLT are prosaic: it is a lot lighter, a fifth the weight of a concrete frame, so it doesn't need deep pile foundations, which would have been problematic with a new Crossrail subway line going underneath. It goes up a lot faster, and in real estate development, time is money. Because the CLT has a bit of insulation value, it needs less additional insulation. Because the CLT buildings have more wall and less column, there is less infill framing. So that overall, the cost often ends up being less than building with concrete.More: Dalston Lane: The world's largest Cross-laminated timber building
I think this might be my favorite wood building of the year, designed to be cheap and cheerful and temporary, but that is now staying put. "It has it all: patterns, views, daylighting and of course, our favorite material, wood." The use of mass timber products delivers a very high design outcome and the quality, visual appeal and atmosphere of highly engineered, clear finished, treated timber is very warm and supportive of an excellent teaching and learning environment. These buildings are just so nice to be in; they work well for everyone.More: Designed to be relocatable, this prefab wood building is so nice it's not going anywhere
Portal frames work because they have very strong, rigid joints that transfer the bending moment from the rafters to the columns, which are often deep at the top and tapered as they get closer to the ground. At the Freemen's School in Ashtead, the columns stay the same depth all the way down, becoming a wonderful louvre feature that is used to support seating.More: Swimming pool in London is built out of wooden portal frames and Cross Laminated Timber
Why wood? What wood? What technologies?It was also a year when we started looking at why we are using wood and other natural materials, and at all the different ways of putting wood together.
This is how it all rolls into a bigger picture -- how we have to build zero carbon buildings and get to them with zero carbon transportation, which really means designing our cities so that we can get around by walking, followed by bikes, followed by public transport. It’s all encompassing, about trying to live a carbon-positive lifestyle. We have to do this, and our buildings are probably the easiest place to start.More will follow on this subject. Why we should be building out of sunshine
Listening to Grace Jeffers talk about our forests made me start thinking about the way we are using wood now. Are we being careful enough? Sure, it is a renewable resource, but is what we are replanting as good as what we cut?
Here on TreeHugger and like much of the industry, we call wood a renewable resource. But Grace Jeffers notes that "Yes, we cut down trees, replant them, they grow, and in this way wood is a renewable resource. But by cutting down trees, we are destroying forests and their unique, unquantifiable ecosystems; therefore, a forest cannot be renewable."
Solid CLT is wonderful, but after listening to Grace Jeffers, I began to wonder, does solid wood make sense, or should be be building like they do in Sweden, where they get incredible quality wood frame construction in factories and now, using robots?
There is a reason that America was stick-built; it is fast and cheap and material-efficient. But being site-built, it was sloppy and leaky. The new machines change all that. They bring wood framing into the 21st century, and they use about a fifth as much wood as CLT does.
Of course there is a place for both, but CLT and DLT and NLT are being used in places where wood frame could do the job. I concluded:
I believe that everything that can be built out of wood should be, but am beginning to think that you can have too much of a wood thing. I am really coming to wonder if CLT has not become too fashionable, when there are other, simpler wood solutions that use less material, save more forest, and build more homes.
Anthony Thistleton and I talked about this when he was in Toronto and he responded with a long and thoughtful comment:
For most mid-rises the CLT is a structural necessity, certainly above six storeys. However the CLT also performs acoustically and thermally as well as providing fire resistance. All of these would require additional measures if we built in timber frame. We are happy that the CLT frame presents the most efficient use of material in the buildings we have completed.
But we are just getting started in this discussion. More: What's the best way to build in wood?
In search of the answer to this question, I visited the factory of Bensonwood, where they do both CLT and frame construction, and came away even more confused. Certainly if you are going to build in wood frame, this is how you should do it. More: How Bensonwood builds a wall that works
- Dowel-Laminated Timber (DLT) and Nail Laminated Timber (NLT) will be used more and more instead of CLT because of cost and competitive pressures.
- The race to be the tallest building will run out of gas, and wood will mostly be used for medium height buildings, say up to 15 floors, the "missing middle" kind of buildings.
- We will see a lot more of the European-style high quality wood frame construction in low-rise buildings.
But we will also see a lot more wood. See all our stories on Wood Construction here.