But what about decorating, plastering, electrics? Surely there are huge labour costs to be saved here? Well, yes, maybe. You know those figures which show that nuclear power stations are net consumers of energy? Apparently, when you add it all up, constructing it, mining the uranium, processing it, reprocessing it, guarding the waste for a thousand years, disposing of the contaminated building etc, it turns out it's not worth it. Well, the same is often true of DIY. Do it yourself building work can become a net consumer of money and materials and the waste products are too horrible to contemplate - divorce, heart attacks, lack of sleep, chemical poisoning, smiling at the dustmen etc.
On the other hand, doing it yourself can be therapeutic, satisfying and save you money too. How to decide: if you can do it yourself and produce a professional quality job, then you've probably saved money (but see carpet fitting above). In the case of the wet trades, plastering and bricklaying, you can enjoy yourself and save a not inconsiderable sum. But be warned: if you attempt these tasks and achieve anything less than perfection then it will be obvious forever. It will come under the same category as disposing of nuclear waste - future generations will have to cope with your mistakes. These tasks are difficult; even professionals lose their touch if they don't do the job every day.
But some DIY-ers are determined to do everything themselves and if they can't do plastering they will seek an alternative, such as covering things up with hardboard. Hardboard figures large in the life of the DIY- er. Go into any builders' merchants on a Saturday morning and you will see men in cord trousers buying hardboard. They are not buying it for its intended purpose, which is lining floors; they are buying it because they think they cannot do plastering. They are using it to cover up airing cupboards and ceilings, which they will attempt to disguise with wood-chip wallpaper and emulsion. And nobody will be fooled and their homes will then be worth less than before they started.
But back to carpets. My neighbour recently fell for the cheap carpet scam; you know, the one where the guy knocks on the door and say he's just finished fitting some carpets up the road and - guess what - he's got enough left to do your front room for pounds 20. Well, the neighbour went for this and decided to save even more money by fitting the carpet himself. But that's another story.
Jeff Howell will be writing a weekly column on construction and building