Wolfe in Transition: wood

After many moons of preparation - of walls, lime work, wood research and planning - it arrived, a truck load of eucalyptus wood from near Porto, 140km or so away. With this + one experienced carpenter, our main house roof began.

Carlos, the local Hulk, nudges this half tonne
beam and lets the block and tackle
take the rest of the weight.

Day 1, wood arrives and sits like heavy lumps on the ground in front of the house. I expect a day of phone calls for cranes and heavy lifting gear (after having seen João, the stonemason, use his mechanical claw to move stone all around).

These guys are different – they use a block and tackle. A “Garibaldi”. A pulley with gears. They built a super basic frame higher than the first floor, and dragged the first 8m mega-beam up to it, then hoisted it with this simple yet life-changing little device. From the 1^st floor they did the same thing up to the roof, and within an hour the first beam was sitting there, all warped and imperfect, waiting.

It was incredible to see how quickly they worked. By the end of day 2 they had created the skeleton of a roof, made from enormous bits of green wood (let it go dry, it's impossible to work they say).

Manuel, lead carpenter, 40 years experience,
lining up first beam to go on the roof

They work with no plans or drawings. The list of materials they ordered was done standing in the empty house, pionting at corners and spaces in the air, pulling figures from their volumes of experience. “8m beam there, 64 rafters to cover both main roof elements, a truss here, and supporting beam there” and so on. Jorge, Mr Sawmill, was there scribbling notes as Manuel fired out instructions. They ignored me and my irrelevent questions.

When it's time to join the wood together Manuel whips out his electric chainsaw, sharp as a needle, and cuts shapes, based on how the wood sits beside another bit. He may draw a pencil line, he may not. A few whacks with a mallet and chisel to clean it up. And boom, it slots into place like it was meant to be. A couple of massive nails to keep it in place and it's hard to see how that roof isn't going to stay in place for centuries – as long as we keep the water out.

Day 2 or 3. Main uprights going into place. How they figured out what height these should be at I have no idea.
Without drawings they must have done it by eye, or rule of thumb, based on the width of the main beams crossing
the breadth of the building, which are about 8m long. Lenght ways, the building is about 16m long.

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Piecing it together

Carlos, whacking out some indents to house the angled trusses.

Temporary brace for the end of roof... Hoping there's
some kind of longer term plan for that one!

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Ilie understandably worried at this stage.

By day 4 or 5, looking more and more roof like...

What am I doing here?

Nikita in the thick of it. Learning.

First he cuts, then chisels

Then checks

Then slips it into place. Nice

This is the only hip-roof we're going to have on the building (alternative to a straight, gable end).

More massive wood, oak this time
to hold up East side of roof.

And floor beams, almost 6m long, 30x20cm size
for the kids bedrooms floor...
Roof coming over this next.

I have been amazed by the skills and confidence of this guys. I ask them if they have any young 'uns coming up behind them, learning their trades. They laugh, regard me as retarded, and explain that no young person wants to do this sort of thing. "People want to learn to design things on computer, not here for real, where it's hard work, takes years to learn". For sure, this isn't something you could pick up in a year or two. It's an art, a lifetime's work. And not particularly well paid.

"anyway" they add "everyone builds their roofs with cement these days". This is a whole other issue, based on a little common sense and no doubt serious financial gain for a few individuals in charge of the concrete industries. But how could the entire architectural and engineering professions have been sold out so easily?

Here's the story:

Why cement? Because they are “resistant, waterproof, strong, long-lasting, cool in summer, warm in winter” (quotes from local builders, home-owners). As they have only been built in this way for the last 30 to 50 years they don't yet know the results of this national experiment. In the UK, many buildings made with cement have started to deteriorate within a 30 to 50 year time span, due in part to the inevitable cracking of cement floors, foundations and walls – cracks that allow water to come in, and eventually cause damp within the building, rotting of any wooden elements and so on.

But cement in roofs never really took off in the UK – or France, Germany, the US and most other places for that matter. This means we don't really have a precedent to measure it against. It seems mighty popular in Spain and Portugal so this should be the area to watch. Here are some of the down sides I can imagine with cement roofs:

Non-breathability. Cement doesn't let moisture pass through, so it can't “breathe”. A bit like a plastic bag. It keeps the rain out, sure, but it also keeps the moisture in. And if you think about how much moisture we generate in bathrooms, kitchens and just breathing around the house... We would need a fairly sophisticated ventilation system to allow all that water vapour out, without letting in too much cold air.

Money. I have yet to find out how much it costs, per square meter to build a cement roof, but I'm fairly sure it's more expensive than wood. Though that depends what kind of wood you choose. We'll get to that later.

Carbon Factor. We now know that to produce 1Kg of cement you will emit 1Kg of carbon dioxide into the atmosphere. Multiply this into the millions and you're talking a fairly major chunk of your national CO2 diet. In fact, buildings in Europe are responsible for around 40% of its emissions. So, you want to cut emissions, why not start there, in the building products themselves ? It really is a no-brainer. Trees are like solar panels: they grow with a happy combination of sunlight and water. Cut them down to make houses and plant more, plant twice as many. Make forestry a part of the building industry. Use local timber, not imported stuff from Scandanavia and you cut emissions further. Learn how to use local wood. Get young people learning about this stuff and you may just reduce carbon emissions. Or just screw the planet and build with cement. It seems there's overwhelming pressure around us is to do just this - so many people make so much money from the status quo. Why change it?

I had better leave it there, lest I rant.

We planted three kiwis last year to grow over the outdoor table, to provide summer shade and winter fruit. They hardly grew, we gradually forgot about the prospect of fruit, and ended up using any old screen for shading erected over a bamboo frame, supported on both granite and wooden posts dug into the ground . By Spring, at least one of the wooden posts had started to rot - mould and fungi were starting to appear half way up, inevitable given the amount of water in the ground all winter. Also, by this Spring, the kiwis started to grow again, and they have almost reached head-high.

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. Temporary cross bracing to the ground keeps it from falling down.

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.

The posts are made from oak chopped from Donald's forest last year, and the central beam is from chestnut coppiced from around our watermill this winter, shown here. We have taken to removing all the bark to prevent the multitudes of bugs and creepy crawlies that live under there chomping away at the sap wood.

So we decided to build a whole new frame partially using the granite posts that we had but mostly from new oak posts. Photos say rest of the story...