Modern glass house

Appearing on our screens in 2012, the Grand Designs cantilevered glass house in Brixton modern glass cube home.

By Hugh Metcalf | 9 November 2020

Known for its local appeal and modern outlook, the Grand Designs Cantilevered glass house in Brixton is a firm favourite with fans.

When it comes to building and renovating projects, Carl Turner and Mary Martin are a couple who just can’t say no. They bought their first house within months of meeting nearly 25 years ago. Since then, they have been on a continual leapfrog to bigger and better renovations since, sometimes two at a time.

But increasingly they longed for somewhere they could stop, tailored to fit their minimal leanings like a glove. Opportunity knocked with a derelict house in Brixton, south London. It had no kitchen, a WC in the dining room, and ‘carpet so rancid it could have walked,’ said Mary. But, there was potential to sub-divide the plot with enough room in the garden to build a separate house.

The exterior of the Grand Designs glass house in Brixton

The house uses 350 glass panels, with 200 on the top floor. Photo: Rachel Whiting

A similar plot two doors up had already done this, parcelling off its garden to make way for an ambitious new-build. So they followed suit, renovating and extending the existing house and designing their dream home for the back. ‘I started off sketching a house the planners would like, with a pitched roof and dormer windows. This was because I thought we would never get permission for anything contemporary,’ explained Carl, an architect. ‘But then we just said: ‘Let’s forget the planning system, design the house we want and make a case for it.’

Watch the episode: Brixton, 2012

First time lucky

And their boldness paid off: permission was granted first time, without even going to committee. Their design – a stack of three cantilevered glass-clad rectangles – might look alien among its Edwardian and Victorian neighbours, but Carl argued that it could become part of a terrace of unique houses on the street.

The only problem now was how to fund their daring design. Carl and Mary broke even when they sold the existing house minus half its garden, so the land cost them nothing, but it took months to secure a £280,000 mortgage for the build, which was topped up with £20,000 savings. And it quickly became clear that this was not enough: cantilevered glass houses don’t come cheap, especially when two storeys have no internal walls and there are heavy concrete floors throughout, requiring a steel frame and 14 concrete piles to anchor it to the ground.

To raise another £250,000 they sold their Norfolk barn, which gave them enough to build without compromise. The final cost was £450,000, plus another £100,000 for joinery and internal fixtures and fittings – which is a steal, considering a Victorian terrace nearby costs around £750,000. Even better, the house would be cheaper to run than any Victorian terrace, thanks to its massive eco credentials. 

The green house

At the time, Carl believed it to be one of the most energy efficient in the country, with photovoltaic thermal (PVT) panels on the roof providing most, if not all, of their hot water and electricity, and a ground source heat pump below the house powering the underfloor heating. They also had a cutting-edge system that sends excess heat from the PVT panels down to the heat pump to improve its efficiency, and they have a tank to collect rainwater for the WCs, washing machine and outdoor taps. The house is  also super-insulated and wrapped in an airtight membraneto stop heat leaking out. Green? This house is fluorescent. But the big question is how locals would react to such a statement building.

Read more: Beginner’s guide to ground source heat pumps