It's well worth visiting Hockerton if you're anywhere near. They run various types of tours. Where do you live?

Best thing you could do, if you're serious about being truly sustainable, is read both Ben Law's 'The Woodland House' AND Barbara Jones' 'Building with Straw Bales' and consider including some of the energy-harnessing systems discussed on here to power and heat your self-build.

I envy your position. I so wish I could go back 30 years, knowing then what I know now.

Joiner - thanks for the advice. I've ordered those two books. I haven't looked at straw bale buildings yet - a very different concept from the thermal mass idea of earthships and the Hockerton project. I like watching Grand Designs (although I mostly feel that the houses featured are far too big and impersonal to be homes - just architectural statements). I've never seen Ben Law's Woodland House! Must keep an eye out for the repeats.

Steamy Tea - I'll take a look at the books you've recommended too - thank you. They look like they're more about the general philosophy of sustainability than directly about construction - is that right? Matt Ridley (if it's the same one) is a biologist isn't he? I read a book of his called The Red Queen (this'll be about 20 years ago). It was about evolution and sexual selection. Perhaps its a different Matt Ridley though.

I suspect this is the first 'SQ' (Stupid Question), but who is Tony?

Cheers!
pbd

Posted By: palebluedotHave you been there djh?

Yes, I went a few years ago.

Hi Andy

Have just watched it - thanks for the link. A great house; a rustic barn on the outside - and a church on the inside. And with proportions that will make it a really comfortable home, unlike most of the Grand Designs I've watched. I'm not sure I'd like to go quite so rustic, but there's no denying that's a pretty much zero carbon home. And £28,000 for a house in Sussex with views like that... that's made of win!

I've just seen it's been included in the Grand Designs Revisited...

There was one thing I thought was a little disturbing though. He was shown using 'Pyro' electric cable to do his wiring, as opposed to normal PVC cables. He said, yes, it's expensive, but not as expensive as a burnt down house. This is not what 'Pyro' is about though. It's a type of cable that will resist being damaged by much higher temperatures than PVC cable - (It's used for fire alarms, emergency lighting, and other vital power applications), but it doesn't mean it will prevent a fire that would otherwise start.

When designing a circuit for power and lights you need to calculate the design current (how much current is going to be used by the circuit) and find the appropriate sized cable to handle that current without overloading (and so overheating/melting/causing a fire). You have to take into account anything that will add to the temperature in the cable, and also anything that will prevent the cable from dissipating heat. Like insulation.

Running a cable through more even a short section of thermal insulation can 'derate' the current carrying capacity of the cable by 50%. While Pyro will not melt like PVC cabling, if an electrical fault is causing a lot of heat build-up, this in itself might be enough to cause the straw surrounding it to catch fire. He'd have a burned down house, but at least the cable will still be intact!

I can only assume that he had a qualified electrician to design and test the installation, so that this is actually safe - but the impression given in the program was that just choosing 'Pyro' would save him from a fire.

pbd

Posted By: palebluedotThere was one thing I thought was a little disturbing though. He was shown using 'Pyro' electric cable to do his wiring, as opposed to normal PVC cables.

Using pyro cable was a meme in the straw-bale building world a few years ago. I don't know where it came from though. The usual advice is to not run water pipes inside bales (condensation risk) and also electric cables (fire risk), so the pyro idea might have come from misunderstanding of the requirements when ignoring that advice.

Got the book out...

(He had a mate, James, an experienced electrician, who wired all the 12v electrics in.)

pps 58-59... "James not only calculated all the cable sizes, he also recommended I used mineral cable. This was to ensure that the cables running through the straw bales were rodent proof and there would be no risk of fire. Mineral cable is a cable coated in copper and mice are unable to penetrate it."

I wonder if there is any problem with using metal conduit, instead of pyro, for wiring through straw? I'd have thought it would be more practical in many ways, would allow wires to be replaced if need be in future and would still ensure protection from rodents.

Hi seascape. Sorry - missed your earlier post. Thanks for the pointers. I really like the combined build and community project idea they have at Hockerton. It'd be interesting to know how they arranged various things like who owns what on the project, and what happens when someone wants to move out (or dies!). This could be very awkward, but they might have some novel solutions to it.

I'll definitely try and get along to their next open day - will be missing one they're having this week :0(

pbd

Posted By: seascapeHi palebluedot - just looked up Hockerton Project - very interesting, so thanks for that.

Can't help with plot prices but do know it's good to research building prices whilst you're looking for that perfect site. The Homebuilding & Renovating Magazine website has info on the selfbuilds they have featured - costs from £38,000, £60,000 to the ridiculous.

Other useful sites could be Walter Segal Trust and Centre for Alternative Technology.