Property: Have you got it upstairs?

The property market is booming everywhere, estate agents tell us, but round my way we're the centre of the universe because we can boast of two booms: a house price boom and a baby boom.

A "happening" place then, Crouch End? Absolutely. So happening, in fact, that it's almost inactive. Contrary to the normal laws of investment, rampant inflation in the value of bricks and mortar is no use to anyone in this part of north London since people don't want to move out, they just want a bigger place in the same area for their new family. The problem is, the people who've got the bigger places don't want to move either, even if they could buy a castle somewhere else with the sale proceeds.

The result is that for those few properties which do come on the market, one extra room can add a huge amount to the price. We bought our two-bedroom flat two-and-a-half years ago for pounds 78,000 - a knock-down price which reflected the fact that just about everything did need knocking down, and then building again. Nevertheless, if we were to sell now and look for a property with the same dimensions but a third bedroom, we would probably face an asking price closer to pounds 178,000.

We haven't got that sort of money, and nor have lots of other people, but that doesn't mean everything has come to a standstill, because Crouch End is now enjoying a third phenomenon: a scaffolding and skip boom. Rather than admit defeat, or try to meet astronomical mortgage demands, people are using their savings either to buy empty "shells" and renovate them, or to convert the cavernous space under their roof.

When we bought our flat, one of the clinching factors (though at the time it was more like a clinching fantasy) was the loft. Admittedly, it was just a tangle of ceiling joists, accumulated rubbish and disused pipes, rounded off by a hole in the roof, no felt underlay and no insulation. To convert the loft, we would also need the consent of the freeholder, planning permission from the local authority, a loan for heaven knows how much from the building society and, for all we knew, the blessing of the president of the world. But as far as we were concerned, if we could carry out the conversion then we would never again have to go through the hassle of moving.

It was probably the element of fantasy in this plan that made us nervous about getting in touch with builders: one sky-high quote and we would have to face the reality of moving again in a few years' time. Meanwhile, talk from friends of such intimidating things as suspended floors and load-bearing walls - like a car mechanic talking about architecture - did nothing to alleviate the feeling that this was a long shot.

So when we finally decided to call in some specialist loft-conversion companies to provide a quote last December, it was more in hope than expectation. The first surprise, then, was the price. Our needs weren't particularly complicated - just to turn a 28ft square space into one big habitable area, with no trimmings except for a staircase and a new roof. Even so, it was reassuring that the four quotes we received only varied from around pounds 17,000 to pounds 15,000 inclusive of VAT but excluding the roof repairs. Not cheap, but a lot cheaper than a hike in the home loan of, say, pounds 70,000 to move house in the same area.

This consistency among the conversion companies wasn't restricted to price: all four also stressed that their work would have to be carried out in accordance with local authority building regulations. This might seem like tiresome bureaucracy - and the process of submitting plans for approval and arranging site inspections is time-consuming and costly - but it is important because it gives the customer peace of mind.

For instance, from the point of view of the regulators, the new loft is treated as separate from your house. It has to have its own point of exit, a fire-escape window in the roof, and a "half hour fire check" frame and entrance door. This means that if a fire breaks out in either the loft or downstairs, the two areas will be isolated from each other.

Then there's the suspended floor, a slightly misleading term to describe steel girders which are hammered into the brick walls in the loft and then form the underpinning for new joists and floorboards. Because of this arrangement you will sacrifice some of the head room since there has to be a gap of nine inches between the girders and the joists for the downstairs ceiling. You will also lose width - our living area came down from 28ft to 15ft - because of safety regulations concerning the span of the plasterboard roof.

Of course, it is possible to cut corners and cut costs. For example, while the joists you walk on in an unconverted loft are there to support the ceiling below, you could just nail new floorboards into the top of them, forget all about the steel beams and hope that the whole lot doesn't cave in the first time you have a loft party. This is exactly the kind of construction friends have encountered after putting in offers for properties where builders have converted the loft. The problem is, the surveys have revealed that the alterations aren't in line with the regulations, and the sellers have had to go back and get the work done again, properly.

Another potential problem is the main load-bearing wall in your home. This may seem solid but if you live in a flat and the person below has decided to make a feature out of the same wall by converting it, say, into an archway, another way might be needed to underpin the loft.

One side-effect of site inspections by a regulator is that he will view not just the loft but the whole property. You might have made modifications to your kitchen or living-room, for example, and no one in authority will be any the wiser. But the moment an official comes in, it's his duty to report on anything that might be a safety hazard. In our case, that has meant a smoke alarm, self-closing mechanisms and proper catches on all the doors, and the glass panels above two of our doors being replaced with boards because they could be shattered by a fire.

So that's the boring old rules, what about sexy things like money? Our choice of builder, Sunlight Loft Conversions in north London, charged us a total of pounds 18,200 including VAT and for that we got a new felt roof with the slates taken off and replaced, the steel girders, the floor, plastered softwood walls and ceiling, two radiators, six Velux pull-down windows (including the fire escape), four double-socket power points and two overhead lights, the staircase, and a five-year guarantee. Less significant, but much more irritating, were the bureaucratic extras. Our bank waived the fee for the pre-conversion visit by its surveyor (carried out to ensure that the value of the property justified the top-up to our mortgage loan) but charged pounds 55 for the second visit, in which the inspector verified that we had indeed used the money for the conversion. Meanwhile, we've had to pay our freeholder pounds 150 plus VAT for "licence documentation" and will be incurring a further pounds 30 plus VAT for a visit by its own surveyor.

So we will have been visited by the building regulator, the bank's surveyor (twice) and the freeholder's surveyor - all of whom should come to exactly the same conclusion. You might think all this attention excessive; I couldn't possibly comment.

Also puzzling was the approach taken by our bank, which agreed to top up our mortgage with an additional personal loan of pounds 12,000 and so seemed to clear the way for us to meet Sunlight's schedule of payments, in which the pounds 18,200 outlay was divided equally over the five-week construction period. I say "seemed" because we had to make a fuss to get any money released before the work began (eventually we received a pounds 6,000 advance), and were also told that the rest of the loan would be handed over only once the surveyor had provided a written report - up to 10 days after his final inspection. We've managed to hurry the process up, but Sunlight says that lending hold-ups have been a recurring problem for customers.

Banks and building societies will claim they have to be sure they'll get a return on their loan - the unspoken message being that a botched job would affect their chance of selling at a profit in the event of repossession. They don't seem to understand, however, that if people like us had pounds 12,000 in cash at our disposal, we wouldn't need a loan in the first place.

Thankfully, the job itself went much more smoothly. Although it's a big project, a loft conversion is probably the least disruptive building work you'll undertake because, at least until the staircase goes in, it all takes place outside your living area. We've played host to scaffolders, carpenters, roofers, welders, plasterers, plumbers and electricians, and at no time have we had to clear out of the flat. It was also reassuring that they were all accountable to the loft company, which in turn was accountable to the regulators.

The only time my nerves were on edge was the day the steel girders arrived. These beams weigh 70kg per metre and the biggest four measured four and a half metres - a weight of 700lbs each. These had to be craned up through the roof and then hammered into the wall by workmen standing on the old joists. While this was going on, our kitchen ceiling was moving up and down like a trampoline. The ceiling survived: my belief that I might live forever did not.

We started talking to builders last December and the work has only just been completed. The hold-up was created by arranging the loan, getting the freeholder's permission and waiting for the plans to clear the building regulator and local authority, which itself took six weeks. In the meantime we moved further back on the loft company's roster.

So was it worth the wait? Undoubtedly, yes: we have a new room with a living space of 28ft (including the landing and staircase) by 15ft and storage areas behind the two long walls - hopefully I won't spend all my time downstairs tripping over toys. Most of all, to steal the old football song, we shall not be moved.