A Good Idea But Not Enough

Via Core77, some excerpts of Clara Mu He’s masters thesis, which propose a way to make wood-frame construction much more amenable to recycling and reuse of materials: here. In short, if you use strapped and ganged lumber sticks rather than special sizes and penetrative connectors, you can later take the frame apart and reuse its components. If you click on the link, there are photos of a model (quite clear) and some drawings (not so clear, because low-res) that make her point.

I’m of mixed opinions about this. She’s absolutely right about the ecological impact of construction and demolition waste, and her designs are very clever as a way to build a wood-stick frame without direct connection. But (you knew there was a “but” coming, right?) her strapped connections rely solely on friction to work, and it’s difficult to see how they will be stiff enough to provide lateral-load resistance. They will work just fine for gravity load, but lateral-load strength will depend on the straps being tight enough to make friction between the pieces enough to resist sideways slippage…and over time, wood shrinks and straps relax.

But (number 2): the wood structure of an ordinary house is not a particularly large percentage of the material in it, and a smaller percentage of the waste. Concrete (foundations), finishes (gypsum board), services (pipe and electric conduit) and machinery (boilers, water heaters, air conditions) matter more if we’re looking at the ecological impact.

But (number 3): the green path to urban densification, which is part of her discussion, probably lies with larger buildings. They are more efficient in their use of materials and energy (for heating and cooling), and more efficient in terms of use of urban land.

I feel a little guilt picking on a student thesis, but I’m going to because Clara Mu He is right on her main point (construction is far more wasteful than it should be) and had a good design idea. So I’m not criticizing her work as much as its context. She’s attempting to solve a very large problem with a solution aimed at a small piece of it.