Senda Verde Permaculture Eco Center
Tuesday, 11 May 2010
Eco Construction building with roundwood
About our project in Northern Portugal to renovate some ruins and abandoned land. But more than this - to apply building and energy systems that are local, renewable and less polluting, more efficient, healthier and cheaper. And to actually learn about how they work practically, so one day we can teach others here and in other parts of the world where crises and poverty are permanent overlords. This is our story, our search, our transition.
This issue of using wood close to the ground in building is a classic design fault common all over the world. In 1997 I worked with Movimondo in Guatemala where a part of their community development project involved showing locals how the use of around 70cm of stone footing for their homes would extend the life of the wooden walls, saving them the financial burden of rebuilding their homes every five to ten years.
Here in Portugal, and also in Scotland, I know that people generally believe it's sensible to sink a post deep into the ground, often bedded into cement for "extra strength". We are also advised to paint the end of the post in tar, or burn it first to prevent rottage.
But Paulo has introduced the idea of using rocks as the principle footing to ensure the posts stay dry and last many times longer.
Small metal bars, around 8mm diameter are inserted into the but of the post, and a similar hole drilled into the rock.
This merely holds it in place - it is really wobbly and insecure at this stage.
Once a few posts are erected, a beam joins them together along the top, with simple lap joints with more metal bar to keep it together. This helps to secure the wobble a bit, but it really starts to get more secure when you link up the posts in both directions and add cross bracing. Rafters helped with stability too.
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