Real Estate

Many new buildings dangerously unprepared for climate change


The British summer of 2018 is set to be among the hottest since global temperatures began to be recorded in the 1850s.

Meanwhile, the World Health Organisation predicts that in little over a decade, nearly two-thirds of the world’s population will be living in cities — many in dense and overheated conurbations.

In our own six-week summer heatwave, which started in June and stretched through July, the UK’s daytime temperatures consistently exceeded 30C, with scientists and environmentalists pointing to global warming to forecast of more of the same to come.

London has a more oppressive climate than the rest of the South East.

Materials such as concrete and glass, combined with a high level of movement from cars and motorbikes, public transport and even the motion of people, help heat up the ground and air during the day while row upon row of tall buildings block cooling breezes.

One recent study suggested that offices in the capital could be using five times more energy by 2050 — simply attempting to prevent overheating.

CAN’T STAND THE HEAT?

In his current plan for London the Mayor, Sadiq Khan, sets out to reduce the impact of the urban heat island effect in London and encourages the design of places and spaces to avoid overheating and heat generation. But are house-builders on board?

The home-building industry is trapped in a vicious circle. In an escalating housing supply crisis and with limited space on which to build, the only way is up.

However, as house-builder Bob Weston, of Weston Homes, has argued, tall towers are more prone to overheating as they have more surface area to absorb sunlight.

Rory Bergin, partner at architectural practice HTA Design, says: “Our understanding of the effects of weather on buildings has come on leaps and bounds in the past five years. However some developers are still too focused on their buildings’ good looks rather than its good performance. Not everything has to be wall-to-wall glass.”

It’s also about getting the ratio of window to wall right. Bergin cites One Blackfriars in Southwark, which is made with 5,476 sheets of curved glass, as the latest example of London’s love of the material.

London builders have had an obsession with highly glazed structures. But they soak up the heat. Critics say glass buildings could become architectural dinosaurs.

PROS AND CONS OF AIR-CON

Air-conditioning offers comfort to office workers and homeowners struggling to sleep in a heatwave but it is expensive to install and run, uses a lot of energy and overheats the outside environment.

“Buyers, both international and domestic, and high-end renters are asking whether a property has air-con before even committing to a viewing,” says Guy Bradshaw of Sotheby’s International Realty.

At Adelphi Terrace — a boutique scheme of 12 luxury apartments in Covent Garden — air-conditioning can be controlled via digital zoning. “This smart system allows it to be one degree in the living room and 20 degrees in the bedroom,” explains Bradshaw. Prices for a studio apartment start from £999,950.

So should air-conditioning units be installed more widely across the different price tiers of the housing market? Certainly not, according to HTA’s Bergin. It intensifies the problem of an overheating city.

“Air-con takes heat from inside and moves it outside, warming the external temperature and increasing the urban heat island, making it hotter for everyone else and therefore making it necessary to use even more air-con. Building unprotected glass buildings that need to be artificially cooled is a poor strategy.”

SHUTTING OUT THE SUN

Bergin favours a simple approach: keep the heat out by making the windows the right size for the amount of daylight needed with shading and shutters instead.

“We should look to our continental neighbours,” Bergin adds. “External shutters are the normal fabric of their residential buildings that they can leave closed during the day. A westerly-facing apartment will get a lot of sun, therefore it should be designed to have dual-aspect windows so that the resident can get a breeze flowing through.

HEAT-RESISTANT HOMES ARE HOT

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Here comes the sun: 101 George Street, Croydon

Construction group Tide is building a 550-apartment development at 101 George Street in Croydon. On completion it will comprise two of the world’s tallest modular towers, part-built in a factory and put together on site, at 44 and 38 floors.

The building is clad in green perforated terracotta panels that let in light but keep the heat out, therefore creating thermal stability.

Each flat will have mechanical ventilation — a high-tech fan that whirrs away silently, bringing fresh air in and expelling out stale air. The outgoing air heats the incoming air keeping bills low.

COLD COMFORT

Some climatologists believe the UK may be in for a mega-freeze this winter, citing storms in the tropics that could force cooler air north to trigger four months of ice storms, Arctic gales and snow.

But Weston Homes’ boss Weston still insists cooling homes is a far bigger issue, as new homes are so well insulated.

His company is building 27-storey Stratford Riverside in east London.

“For our tower we managed to get the local planning authority to agree that we can use individual air-source heat pumps in each property to bring in heat from the outside and release it inside, a system that both heats and cools the home,” he explains.

Weston also says that each home should have its own boiler. “In our Dartford scheme Langley Square we have avoided a centralised system. Each buyer has control over the temperature in their property, and that individuality allows them to switch energy provider.”

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Temperature control: each home at Langley Square has a boiler

New tall buildings may also need to be constructed to withstand stronger winds and storms, another result of global warming.

HTA Designs Bergin explains the problem: “Concrete and steel both have natural flexibility but there is a balance to be struck. They cannot be too stiff and brittle, or too flexible because that makes people nauseous and the lifts won’t work.”

What is clear is that climate challenges may mean London has to end its love affair with glass towers — with house-builders finding new ways to seduce us.

A HOUSE FOR ALL SEASONS: ‘I WANTED IT TOUGH AND SIMPLE’

Building engineer Scott Smith, who builds skyscrapers in the Middle East, is reaching the completion of his own self-build project in Harpenden.

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Self-build: Scott and Jocelyn Smith wanted their new family home to be able to stand up to extreme weather (Adrian Lourie)

With his wife, Jocelyn, an interior designer, he knocked down a Sixties house in the affluent Hertfordshire commuter town to use the land.

Heating their new five-bedroom home was a priority for the couple, who have two children. “The house is up to the energy-saving standards of a Passivhaus,” says Scott. “It has a full cavity insulation system — a solid foam block between the inner and outer walls, two boilers, and thus two heating systems, so the whole house is not being heated at the same time but switches from one to the other at different times as we move from downstairs to upstairs.

“I wanted a house that could stand up to extreme weather but which was also simple, so avoiding additions such as solar panels which can be expensive to install and difficult to maintain.”



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