The new converts

They arrive at 7.30am every morning, make their own coffee and tea and don't call me ‘love'. I am feeling optimistic," said Suzanne Lazarus about Cox Format Developments when the building firm was halfway through her loft conversion.

She was right to feel optimistic. The company has just completed the £30,000 month-long job on time and on budget. Once the decoration is complete, Suzanne and husband Steve will have a new bedroom and en suite bathroom to slumber and splash in, and 14-year-old daughter Rosie will have lots of new-found space in which to stretch her teenage limbs: she has inherited her mum and dad's old bedroom.

"I think Rosie's old bedroom will become my quiet room. We certainly haven't had one of those till now," says Steve.

They also haven't had a good experience with a builder until now. The loft conversion is the third big project the Lazaruses have undertaken on their north London home. The first was a small extension, the second some work on their driveway. Both ended in disaster and the second resulted in a court case. The couple won, but on learning of the verdict, the firm declared itself bankrupt, leaving the family without a penny in compensation.

Suzanne still bristles when she sees the full-page ad the company, now trading under a new name, runs on the back of her local Thomson directory.

"So, yes, we were nervous before starting the job," admits Suzanne. "The other guys were just kids whose 10-year guarantee meant nothing. What matters in this industry is the experience and quality of the craftsmen."

She was reassured to see the men on company director Peter Maton's team - TrustMark registered and winners of the 2005 Barnet Council Considerate Contractors award - were largely middle-aged with years of collective experience.

For Peter, experienced clients are important too. "Even in a straightforward job like this, it's great to have a lucid client who doesn't keep changing his mind," he says. "The glut of makeover TV programmes means people are generally more informed about building works than they used to be. But I am still, for example, amazed at the number of people who want to pay for work up front."

The Lazaruses didn't offer to do that, but they will be happy to settle when the job, which included £4000 of roofwork, is completely finished. So far, they couldn't be happier with the result and the working relationship that preceded it. "Even though the project's real test will come in six months to a year's time," warns Suzanne. "Let's see if everything is working properly then." Steve is slightly less cautious. "I now think you get what you pay for in this industry," he says.

Unfortunately for Steve, the loft conversion meant the landing ceiling also had to be destroyed. The clouds of dust this generated was, he says, shocking. "I think we'll be dealing with the dust aftermath for weeks." But given that the demolition was unavoidable it was not something to kick up the dust about.

Week 1 - High expectations ...

Putting in the floor joists on the web of fireproof steel beams which sit on a concrete padstone. Some firms may have cut corners by using lighter gauge steel that was not fireproofed.

Photograph by Ed Jones

The old roof is stripped off, showing the original batons, and breathable felt is installed. The less scrupulous could simply put new tiles on the original boarding and not install the breathable felt. Without the felt, airflow would be impaired and the building would probably suffer from condensation.

I now think you get what you pay for in this industry

Steve Lazarus

Photograph by Ed Jones

Week 2 - ... it's taking shape ...

The roofing batons and breathable felt are visible on the exterior.

Photograph by Ed Jones

SuperQuilt roof insulation was used in the eaves.

Photograph by Ed Jones

Week 3 - ... work in progress ...

The walls are ready for plastering. Rockwool insulation is complete, offering a good sound barrier - particularly important here since the couple’s bedroom has an en suite shower room.

Photograph by Ed Jones

The staircase provides at least 2m of headroom – not always easy in a tight loft conversion. In addition, a staircase’s maximum pitch should be 42 degrees, while the treads should be a minimum of 8in wide and 9in deep. According to the buildings inspector who approved this job, poky staircases are the downfall (no pun intended) of most British loft conversions.

Photograph by Ed Jones

The new roof with its batons.

Photograph by Ed Jones

People are generally more informed about building works

Peter Maton

Week 4 - ... it's nearly there ...

A good builder will ensure that your new spindles and handrail match your existing one. “It’s about taking pride in your work,” says supervisor Keith Murphy.

Photograph by Ed Jones

The windows are not made with just any glass. It is insulated Pilkington K glass, as the stickers clarify. How many customers end up looking at the world through ordinary glass? Using thinner sealed units, builders can save 10% on their window bill, says Maton.

Photograph by Ed Jones

It’s all systems go for the Velux windows.

Photograph by Ed Jones

Week 5 - ... looks like a top job

The fire-checked doors and electricity points and downlighters are all in place. It almost looks like a bedroom.

Photograph by Ed Jones

The old roof next to the new one.

Photograph by Ed Jones