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The freezing cold 1855 house that was up for sale in the winter of 2013 used to be a tutorial annexe of Goldsmiths, University of London but had been empty for four years.

The place was dire, with no bathroom except a single loo in a tacked-on structure, and a tiny kitchen extension like a Salvation Army tea counter.

Add to the picture rising damp, ripped-out windows, a collapsing spine wall and the spooky appearance of an office apparently abandoned at short notice.

WHAT IT COST House bought in 2014 by private treaty for an undisclosed sum Works, with Henri as project manager and architect: £300,000 Value now: £1.45 million

However, all this excited architect Henri Bredenkamp, 38, and his artist wife, Clare, 37, when they went to view it.

They were not bothered by the fact that the building in New Cross SE14, originally an ordinary terrace house, was now zoned for commercial use. This meant that any buyer, prevented from getting a normal mortgage or living there, would have to apply to the planners before turning it back into a house.

Exciting prospect: the terraced house had been zoned for commercial use and change-of-use permission was needed from the planners (David Butler and Salt Productions)

Confident that they could sort it all out, Henri applied to the planners at once but asked the agent to hold the property while he did so.

The change-of-use process can take eight weeks, but Henri got letters of support from local residents who were thrilled by the idea of a family taking over this ugly, decaying building, and he received permission in a record 21 days. He immediately put in a planning application for alterations.

Set on three floors, with a divided, dark basement, the house needed gutting, though the couple salvaged a few original details including a nice pair of doors, a fireplace and grate, and a curvy mahogany handrail.

Henri was a busy working architect, and Clare was looking after their baby, also called Henri, but the pair put their north London flat on the market and got cracking.

Henri Snr says: “I knew what I wanted to do the moment I walked in.” At a local café he quickly sketched what would become the blueprint of the planning application. The builders started basic clearing soon after, and dug the garden down 6ft 6in, to match the basement level. This alone brought much more light towards the back.

Bring the outside in: full-width glass doors open to the garden (Salt Productions)

Now, you come down new stairs from the hall and enter an unexpected new double-height glazed area, leading out to the garden, with soaring views of the sky. The new kitchen takes up the whole former basement area, while a new living area extends out, its garden view enhanced by a full-width run of sliding/folding doors.

WELCOMING AND COSY

The welcoming kitchen has a gorgeous French bistro effect, and unlike soulless white kitchens, it is cosily darker. A long central bar has a gleaming concrete top that was cast experimentally in the garden. The technique, which avoids polishing, is now a staple of Henri’s designs.

Steel cabinets down one kitchen wall add an attractive glow, while the opposite run of cupboards is painted black, to be drawn on in chalk. At the end of the kitchen space the carpenters built a double display cabinet backed with ordinary mirror glass, which reflects the garden, and resembles a window.

Tucked in between the new stair and the party wall is a narrow bathroom smartly lined with vertical metro tiles. Back upstairs, the hall has been widened, making a much better space for coats. Between the master bedroom and baby Henri’s bedroom, another bathroom was carved out as the couple’s en suite, smartly lined with small glass tiles. As the bathroom space is stolen from Henri Junior’s room, a softly curving back wall makes this intrusion attractive.

On the top floor, there’s an art studio for Clare in the loft extension, done under permitted development rights, with tremendous views towards the Shard through one big picture window that’s encased in bespoke plywood.

Art studio: loft extension, with picture window and Shard view (Salt Productions)

This house has had so much work done to it, and come together so well. It’s now a dramatic, light-filled space — and a really lovely family home.

It has three bathrooms where it had none; an industrial-looking kitchen you don’t want to leave, plus a gently landscaped garden focused on one mature olive tree.

Yet all that was done by adding only about 12 per cent extra space. It’s using space in the right way that makes all the difference. “We thought we’d often open up the glass doors and eat outside,” says Henri. “But the light is so good that we spend most of our time inside, and it feels like being outside.”

The Study House won the prize for Best Value in this year’s Don’t Move, Improve! Awards, announced last week by New London Architecture.

HENRI AND CLARE’S ECONOMICAL TIPS

Ordinary mirror glass at the back of a glazed cupboard enlarges the sense of space, reflects light and draws the eye

Concrete cast with phenolic ply is automatically shiny like polished concrete

Painting a defined black area around a young child’s bed makes a lovely place to scrawl with chalks

Henri’s design: the kitchen's central bar with gleaming concrete top; and bespoke steel handles on steel Ikea kitchen unit fronts (Salt Productions)

Bespoke steel handles on steel Ikea kitchen unit fronts look a million dollars

Just one mature tree in a planting scheme makes the whole garden look established

Spend where it matters. The lower floor is now the deserved soul of the house

Transformation: the basement and garden are now on a level (Salt Productions)

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