Stuff News - Peter Olorenshaw 05:00, Jun 07 2019
OPINION: There is a significant opportunity to slash our carbon emissions that we may be missing. It's an opportunity that does not involve extra cost, just by thinking a bit differently about how we build our buildings.
Currently we are most likely to build our commercial buildings by using highly energy intensive materials such as steel and concrete. These materials come at a high carbon cost that we currently all but ignore, but more than that, they come at an opportunity cost of missing out on using other materials that store sequestered carbon.
By using timber in our buildings, not only do we side-step emissions from carbon intensive materials, we also lock up carbon in the timber fabric of the building - a double whammy for attacking global warming.
We need to see our buildings as carbon banks where we can store the carbon absorbed by trees for decades into the future, if not in perpetuity. We need to have a "wood first" approach to building where you have to have a very good reason for not using timber beams, columns, floors, claddings and linings in our commercial buildings as well as our houses.
Weight for weight engineered timber is about as strong as steel, and while we need bulkier timber members for equivalent functions, we can design for that. Perhaps surprisingly, heavy timber columns and beams can perform well in fires, thanks to the charring process on the outside which protects the interior structural timber.
With our houses, building with timber framing is already the default option. But by using timber floors on driven timber piles rather than concrete foundations and floor slabs, we can avoid significant carbon emissions, while at the same time improving resilience to earthquakes and flooding. And we are storing sequestered carbon at the same time.
In many of our expensive houses we too readily jump to using steel beams when we could have designed them out with some tweaks to planning and/or using engineered timber instead.
Our region has nationally significant production facilities for structural timber products, using locally grown timber. By using those products, we "buy-local", supporting the local economy and minimising transportation costs and emissions.
Helping councils navigate the climate emergency individual buildings
Easy: planning controls allow 500 mm extra height for houses with timber floors. (Encouraging use of timber without penalising design).
Middle: Commit to all new council buildings being CO2 neutral in construction and operation. Big: Require "embodied emissions" calculations for all building consents, and include market-rate CO2 offset charges with all building consent fees.
Think about: Requiring "BAMB" (buildings as materials banks) circular economy requirements on a high percentage of new building components.
So, the next time you are talking about new buildings, ask about aiming to be carbon negative. Ask for a building that stores more carbon than emitted during its construction, as well as in use.
* Peter Olorenshaw is a well-known Nelson architect, has a strong track-record in sustainable architecture, and in advocating for effective climate responses. Olorenshaw also convenes Nelsust, a long-established organisation promoting people- and climate-friendly transport for the Nelson Region.?