There was once a time when adding a conservatory to a home was thought to be the height of sophistication.
They were additions to be envied – and reserved only for the wealthy who had big houses and even bigger gardens.
But times have changed and conservatories have now become dated. Still useful but old-fashioned.
Clear benefits: Catherine Polli’s 42 sqm ‘glass box’ extension in Greenwich, South London
Instead, contemporary ‘glass box’ extensions which have barely a brick or frame in sight are an increasingly common sight.
Catherine Polli, a lawyer who lives in Greenwich, South London, had a 42 sqm glass extension added to her Georgian home’s kitchen in December 2019, designed by Matthew Giles Architects.
She opted for a glass box rather than standard bricks in order to make the house brighter, which suits life for herself, her husband and their two children.
‘When we bought the house, the kitchen wasn’t functional for our needs. It was long and very, very dark,’ she says.
‘It’s a massive property and felt quite oppressive because there was so little light.
‘We spent all our time in these huge reception rooms because there was nowhere else to go, but now the kitchen is the hub. So the aim was to make the kitchen bigger, but also to increase hugely the light through the property. And the kitchen has doubled in size.’
Building with large pieces of glass does not come cheap, however. The Polli extension cost about £100,000 and required planning permission.
But it means the family can enjoy the garden year-round, even when not actually sitting in it. The room doesn’t get cold due to the good thermal properties of the double-glazed glass and underfloor heating.
‘It gives us inside-outside living because the glass opens out onto a patio area. During the summer it felt like the garden was part of the house — there’s a lovely magnolia and other trees. It’s fabulous.’
Carly Coren from IQ Glass says almost any homeowner could have a glass box extension because they are very adaptable.
‘You could have one on the ground, or on the roof, in the garden — anywhere, really,’ she explains.
Her favourite projects are those on listed and heritage properties. ‘They combine modern and traditional elements — the contrast creates such a unique finish.’
She points to a number of clever technologies that can be built into the glass itself.
As well as glass with strong thermally insulating properties, or thermally broken glazing, which adds an extra barrier within the frame to prevent heat loss, you can have heated glass that itself acts as the primary heat source for the room.
Clever technology: Modern ‘glass box’ extensions offer a minimal design, and the glass can be treated to avoid cold and noise coming in from outside
A current is passed through a layer on the glass so there’s no need for radiators or underfloor heating. Like normal central heating, it can be set to activate when the room temperature falls to a certain level.
‘It’s good for anyone who wants a really minimal design,’ Carly says.
At the other end of the scale, polarised or solar-control glass, which prevents shortwave radiation passing through, will prevent you being dazzled or roasted on a summer’s day.
Or acoustic-reduction glass will mean you aren’t troubled by traffic noise if you’re close to a road. ‘With structural glazing, there aren’t really restrictions on size, shape or structure so the options are limitless,’ she says.
We wanted a lot of light and my husband is obsessed with glass and modern design. He’s happy with what he got. It’s sunny, light and beautiful.
Valeria Pensabene, homeowner
Charity manager Valeria Pensabene had a 36 sqm glass extension added to her Victorian house in Hampstead, North London built in 2018 by Glass Structures Limited, which would charge about £50,000 for a similar structure. It has turned the kitchen into a large open-plan family living space.
‘We wanted a lot of light and my husband is obsessed with glass and modern design,’ she said. ‘Well, he’s happy with what he got. It’s sunny, light and beautiful.
‘It’s changed the place completely. It doesn’t even compare to what we had before. It’s the nicest room in the house now, so we spend most of our time there.’
It’s especially good for making the garden part of the house. ‘It feels like you’re in the garden and looking at the wildlife is good for happiness and mental health.’
The triple-glazed glass prevents the room getting cold in the chilly months. ‘And if it’s a sunny spring day, we have to wear shades — I’m not joking.’ There are also sails in the garden to shade the extension in the heat of summer. ‘When our friends see it, I always get a ‘Wow’.’