Open house

HOUSE STYLE: A modernised, early Victorian house is one of many open to the public this weekend

When the architect Bernhard Blauel and his wife, Mina, were looking for a family home in 1992, they had to anticipate their needs for several years ahead. Would the house be suitable for a new baby? What if they wanted to rent out a room, or their toddlers grew into teenagers who needed their own territory? Would they be able to accommodate an ailing parent? What if they decided to run their business from home and the business then outgrew the home?

The solution, if you can afford it, is to buy a five-bedroom house in a desirable area with a granny flat and at least two entrances. Such houses usually have a pounds 500,000 price-tag, so Blauel designed a completely flexible home within the frame of a derelict Victorian terraced house that cost only a third of the price.

Currently, it is a three-bedroom house with a ground-floor living-room that is open-plan to the kitchen, plus a large one-room extension that houses his office. If the office outgrows the home, it could become a stunning extra living room, but it has been designed to divide easily into another two bedrooms and a bathroom or a separate one-bedroom flat for a teenager, nanny, grandparent or tenant. And because the whole house was renovated with a steel frame, rather than rebuilt with the standard method of load-bearing walls, tearing down a wall or putting one up should be little more trouble than replanning a room. The living room could easily be turned into two rooms, and the kitchen could be open-plan to the hall rather than the main room. The plumbing and services, too, have been laid out with the aim of making access and re-routing a simple job.

As an architect, Blauel first considered building from scratch, but finding a plot in London - or any other big town - is almost impossible. And big warehouse conversions don't necessarily make ideal family homes. That left the standard terraced house, whose two-on-two room layout and long, thin shape is familiar to every city-dweller.

The Blauels found a rundown, flat-fronted, early Victorian cottage with a small backyard, conveniently located for the City and the West End in Kennington, for pounds 69,000. Then Blauel designed a layout that could absorb the typical changes of family life over several decades, setting himself a budget that guaranteed their money back if they wanted to sell.

The Blauels faced the extra challenge of strict conservation guidelines, which limited what they could do. But Bernard specialises in modern additions, or conversions for period buildings, that are sympathetic to the ideal, without actually copying the period style. "I worked with English Heritage throughout the project, and they have told me that this is a good example of a period home evolving to meet the needs of contemporary life," he says. And although the interior looks hi-tech, with steel-mesh walls and open fireplaces, an owner with more conventional tastes could easily replace them with brickwork, and add mantelpieces and other period detail.

All the walls had collapsed behind pebbledash render, and the interior had to be gutted. "At one point," says Mina, "we had demolished so much that the building society wouldn't give us enough money to go on to the next stage, because the actual value of the site was less than the sum of money we needed to borrow." This is, apparently, a common Catch-22. Building societies lend money according to the value of the house and, if you are doing a conversion, lend it in stages on the assumption that each phase adds value. Demolition doesn't always come into that equation, and the Blauels, like many other private renovators, had to finance the next step privately.

To extend the cottage, they had to work within strict planning guidelines. They could add no more than 10 per cent of the total floor space, and the boundary walls were not to be raised above 8ft. The new extension runs across the back wall of the yard, linked to the original L-shape and creating a house that goes round three sides of a small patio. The Blauels sunk the floor of the extension a few feet into the ground to give the room a good ceiling height. Although they couldn't create new windows, an opaque white glass and zinc roof give it both light and privacy, while on the patio side, the "wall" is effectively one big window in sheet glass, so it has the airy feel of a conservatory. There are now five people working there.

Even fans of terraced houses admit that light is a problem, as the buildings are so long and thin. Blauel has created a house where light floods in from every angle by having a light-well in the roof over the staircase, and another double-glazed, strengthened window, instead of the old back wall, facing on to the patio.

Inside the main house, Blauel tinkered with plans for several variations, all of which could still be carried out if the family's needs or tastes change. They finished up with a sizeable hall and stairwell with storage, and one main living/dining room with a small open-plan kitchen off it. A division of expanded steel mesh between the hall and living-room enhances the feeling of space and light.

English Heritage required them to render the house in either white or hopsack (sand-coloured). "We chose the hopsack because it seemed a more natural colour and it is more forgiving of imperfections than pure white," says Blauel. He admits to not having replaced some of the decorative stucco band around the house yet, but he has paid close attention to the windows. "They're not exactly the same as the neighbours," he says, but in fact many of those would have been changed in Victorian or Edwardian times.

"When we first started we thought this house would be an intermediate stage in our lives," says Blauel. "But now I think we'll probably stay here a long time because it can fulfil all our needs and we love the sense of light and space"

Opening now, near you

The Blauel's home at 37 Claylands Road, London SW8, is open to the public from 1-5pm tomorrow as part of Heritage Open Day (14-15 September) and London Open House.

Heritage Open Day is a Europe-wide initiative to open up buildings of special merit to the public. These include clubs, institutions, company offices, government buildings and private houses. Architects, students and historians will also be giving tours. Entrance is free, although a few venues require advance booking. Detailed lists can be found at Tourist Information Centres and participating local libraries. For more information on London Open Houses, call 0891 600061. You can reach the Heritage Open Day hotline on 0891 800603. Other homes participating include:

24 Mackeson Road, London NW3 (Sunday 2-5pm). A Victorian house with an extraordinary bathroom in the roof.

Malmesbury House, The Close, Salisbury, Wilts (Sun 2-5.30pm). Dating from 1704. It has one of the finest Strawberry Hill Gothic plasterwork ceilings to be seen, plus a secret hiding place in the orangery.

Sandycombe Lodge, 40 Sandycombe Rd, St Margaret's Twickenham (pre-booked only 0181-341 1371). The only house ever designed by JW Turner. 11 Wallside, The Barbican (Sat 10am-5pm). A quintessentially Sixties apartment flat updated for the Nineties.

Hutton-in-the-Forest Penrith, Cumbria (Sun 10-4pm). Owned by Lord Inglewood, it is one of the ancient manors of Inglewood Forest and is a Medieval Pele tower with 17th-, 18th-, and 19th- century additions.

Concrete House, Bristol (Saturday 10-4pm). Phone 0117 973 7373 for address. Classic 1930s modern movement house retaining most of its original fixtures and fittings.

Alder House, Atherton, Greater Manchester (Sat & Sun from 1pm). Pre-book on 01942 889895. Grade 11 Listed house built in 1697 with 1820s addition.

Pengersick, Praa Sands, Cornwall (Sat & Sun 2-5pm). 12th-century Medieval castle turned into a fortified manor in Tudor times. Now centred round a superb newel staircase.