Kevin McCloud: How to embark on an odyssey of passion, aspiration, creativity and pure effort

Building your own house s a primal urge, one of those universal genetic drives like the need to provide for your family. It's also a mammoth and somewhat frightening exercise that can take years to complete and cost so much you could stump up a Premiership footballer's wages for a few months instead.

That's why it makes good television. Grand Designs wouldn't have just aired its sixth series if self-building wasn't the kind of Herculean task only the very brave or partially potty would contemplate. I've stood on and watched as countless self-builders risked sanity, solvency and even spousal relations, all to make the dream of building their own home come true.

As with so many aspects of life, the "no pain, no gain" mantra rings true here. Self-builders are the adrenalin junkies of the DIY world; it's the equivalent of base-jumping off the top of the Gherkin to land in a paddling pool. A successful project is a personal odyssey, the product of passion, aspiration, creativity and sheer rosy-cheeked effort. The rewards are huge, and, unlike the rush of the extreme sports fanatic, long lasting. Your home will bring years of pleasure, a chest that puffs up with pride, and the sort of streamlined living that only a place tailor-made to your exact needs can provide.

And despite the times of trauma, the process itself can be great fun. For every moment spent battling to get a tarpaulin over your timber frame in a force eight gale, there are plenty more periods of quiet satisfaction - when the glazing slots seamlessly into place, or the second fix goes smoothly. Self-building must be worth the effort - otherwise Grand Designs wouldn't have ballooned from a TV series into a magazine or a twice-yearly exhibition with hundreds of thousands of visitors.

The kind of pioneering spirit who chooses to face the building site alone is usually an early-adopter. Technology that still hasn't become part of the big housebuilders' vocabularies is being bandied around like old-hat on self-build discussion forums the worldwide web over. This is most evident when it comes to the environment. The little people are the ones going a shade of green that should make big business blush. Living an environmentally responsible lifestyle can seem like a Scrooge-like list of don'ts. Don't take that flight, don't buy that car, don't eat those blueberries flown in from somewhere far-flung. But in the home, you have a chance to explore the positives. Do cram in more insulation, do collect rainwater in a tank. Or, like me, do instal a huge biomass boiler at great expense. It's worth every penny.

It's also necessary. If the rest of the world used resources at the rate we do in the UK, we'd need three planets to keep us going. Even those with the shakiest grasp of maths can see the problem. Of course, it's not all down to the individual. But, like charity, sustainability can begin at home. You needn't rush out and instal a wind turbine the size of Nelson's Column on the roof. It's more practical and effective to start using less power. So insulate, insulate, insulate. Get energy-efficient lightbulbs, and A+ rated white goods. And when you've finished watching that episode of Grand Designs, turn the TV off, not on to standby.

But not everyone has the time or inclination to bestride the world of domestic architecture like a self-build Colossus. This is where prefabricated housing comes in. No, I've not lost my marbles. Prefabs are no longer those ugly huts made of asbestos and fibreglass thrown up to house the overspill from fourth form geography lessons. The modular housing market is now a stylish - and eco-friendly - place to be. With the help of a big, expert company, you can get a home designed to serve your needs, and the planet's. The Germans are coming, bearing pitch-roofed, extensively glazed Huf houses, and builds by Baufritz so eco-friendly they're not only carbon-neutral, but carbon positive.

Visitors to Grand Designs Live London can find out more about all of these issues over the course of the nine-day exhibition, running from 3-11 May in London's ExCeL Centre. You'll be able to get your hands dirty and have a go at a traditional build technique, like straw bale building or lime plastering. You can experience the future in a house kitted out with all the latest technological developments. You can also find out how to use a four-metre square plot of land to grow fruit and vegetables all year round. You can have a one-on-one consultation with an architect, or with an expert in another field, like structural engineering, finance or interior design - for free.

You can attend seminars on all sorts of subjects, and there'll be the usual plethora of exhibitors showing their wares in the six-part show; Build, Interiors, Kitchens, Bathrooms, Gardens and the Design Shopping Arcade. All in all, it'll be a grand day out.

Kevin McCloud is a designer and presenter of Channel 4's 'Grand Designs'