Archive for the ‘environment’ Category

Guest post: Mimi Hui – Green roofs

Friday, October 17th, 2008

Whilst I am on blogging “sick leave”, I have invited anyone who fancies it to write a guest blog post. If you’re interested in contributing a self-build, green or cat-related post, please email me! Meantime, many thanks to Mimi Hui for this contribution.

On a cold winter evening in Westchester, NY, I huddled in front of our massive fieldstone fireplace to stay warm. As I gazed upwards towards our cathedral ceiling to admire the sheer beauty of the structure, it hit me that our gorgeous 19 foot uninsulated slate and wooden beam ceiling was primarily responsible for our super high gas bills.

As a young couple that had just poured every bit of our last pennies into an old (but gorgeous) house, we felt ill every time we received the utility bills.

This was how my obsession with roofs started. We were simply trying to cut cost.

Fast forward 10+ years and I’m sitting in Ben’s kitchen in Mountain View, CA. It’s a particularly warm day and he half jokes about his “passive solar energy house”. My ears perk up. He explains that the roof pitch optimises energy from the sun to allow for seasonal changes. In the winter, the house naturally stays warmer as it absorbs more sun. In the summer, the pitch deflects the sun to keep the house cooler. I was impressed. He laughed and claimed it to be “just dumb luck”.

However, this provoked me to visit the new California Academy of Sciences building to get a good peek at its green roof, designed by architect Renzo Piano. This was absolutely breathtaking. It is one of the most gorgeous green projects happening in the Bay Area.

However, this made me wonder, how accessible is green roofing to the average consumer?

Well, the installation of green roofs seem to depend highly on where that consumer is located. And no, it’s not just those wacky Californians that are rushing out to install green roofs (in the USA, it’s actually Chicago, IL that leads the US in green roof installation – ~520,000 sq ft of the stuff).

Germany has seen a proliferation in green roofs, largely thanks to some very progressive environmental policies in the way of financial subsidies. The city of Stuttgart, well known for being a highly industrial area, has used green roofs to improve the overall air quality of the city.

In the United Kingdom, adoptation varies quite extensively. Also, the 2007 Chelsea Flower Show’s inclusion of a roof-garden category redefined people’s perception of a green roof from simply being a passive roof to an oasis of escape.

Turkey’s “Mesa Hospital” has won design awards for its green roof but when I glanced across the rooftops of my hotel there, the everyday citizen seemed to take advantage of plants on roof top gardens and balconies more than anything else.

Overall, it seems that despite governmental subsidies, green roofs are still largely installed by corporate and governmental bodies than the average consumer. Should you be interested in installing one for your home, here’s are a few starting points for research.

- Mimi Hui

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Bury trees, or use them for building?

Friday, June 13th, 2008

Whilst I was away on holiday in the US last week, I had plenty of time to do some reading, and I took the opportunity to work my way through half a dozen recent issues of the New Scientist, as well as read some American house building magazines. I came across some interesting stuff, one of which was an article by Richard Lovett entitled Carbon Lockdown (3 May, page 32 (behind a paywall)), which posited that a good way to reduce CO2 in our atmosphere would be to grow lots of trees for burial, thus sequestering the carbon underground.

Atmospheric scientist Ning Zeng is convinced that if we buried enough trees – where ‘enough’ equals ‘half the trees that grow each year’ – in such a manner that it doesn’t decay, we could offset all our fossil fuel emissions. Other schemes involve burying ‘biochar’, which sounds a lot like charcoal, or hydrothermally carbonised biomatter.

Another tactic is to reinvigorate the wold’s marshes and bogs, which naturally sequester CO2 in plant matter that’s turned into peat. This is already being done in places, not just for carbon sequestration but also as a way to protect and extend endangered habitats.

But here’s a thought or two. Firstly, it’s not an either/or situation – we can probably embark on all sorts of carbon sequestration projects. No one method is going to save the world on its own. Secondly, instead of burying wood, why not just use more of it in building and furniture making?

Wood retains its CO2 content so long as it’s not rotting, which means that wood used in a house is as good as wood buried in an anoxic environment, so why not use more of it? Our forefathers grew wood as a crop, projecting their needs a couple of hundred years into the future and planting trees accordingly. Many forests are now similarly managed, and if we treat wood as valuable crop, instead of as a sacred cow, we can use a lot more of it than we currently do.

I’ve noticed that some environmentalists feel that chopping down trees is the biggest sin we can commit, but we need to draw a very clear line between sustainable and well managed wood resources where trees are planted to replace those cut down, and pristine forests that are being raped and pillaged by ruthless loggers and desperate farmers. We need more crop trees, and we need to go all-out to protect our endangered forest habitats, but we can’t turn our back on all wood and treat every tree as if it’s sacred.

The way I see it, more wooden furniture, more wood used in house-building, and more innovative uses of wood, such as turning it into insulation, could both reinvigorate our forest-based economy and help us sequester carbon. A side effect would also be to provide us with a higher-quality and longer-lasting furniture, for example, or a warmer feel to our car interior finishes – nicer, more enjoyable day-to-day environments.

Burying wood seems like a waste when we can do so much more with it.

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