12 Feb 2024

Urban Issues with Bill McKay: Can we turn carparking into homes?

From Nine To Noon, 11:45 am on 12 February 2024

As people work and live differently in cities, car parking buildings are increasingly under-used.

One solution is to retrofit them for other uses, says Bill McKay, senior lecturer in the School of Architecture and Planning at the University of Auckland.   

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Photo: Jordan Graff/Unsplash

Younger people are moving away from car ownership, he tells Nine to Noon.

“Young people and people living in apartments are moving to other modes of transport, walking, cycling, scootering, buses, trains, taxis, Ubers and car rentals.

“This is a concept called mobility as a service, you don't need to own a car in the big city anymore.”

Alongside this, he says, councils are discouraging inner city car use and apartment developers are including fewer car parks in their buildings.

“And it's become very common overseas now to design new car parks in a way that allows them easier conversion to other uses, particularly apartments or hotel rooms.”

Retro-fitting existing building stock makes environmental and economic sense, he says.

“We call this kind of thing adaptive reuse and car parking buildings they’re generally reinforced concrete and sturdily built because they’ve got to hold a whole lot of weight.

“Concrete has a very high carbon footprint. And it doesn't make sense to demolish all that and chuck it into a hole in the ground and then build another structure all over again.”

People are often unconvinced by the idea that cold, dark, damp car parks could make attractive housing, he says, but it all comes down to design.

The low ceilings are a trick of the eye, he says, because of the openness and the breadth of them.

“One solution is to actually cut out every second floor and then you can fit in little mezzanines.”

The problem of cold and damp is a relatively easy fix too, he says.

“Once we adequately clad them and roof them, then the expanses of concrete are actually very good.

“Concrete’s not an insulator, it has what we call thermal capacity. So, it can either store coolness in summer, or store heat in winter what we call passive heating; so sunlight falls on the concrete floor or tiled floor granite, marble, It will absorb it and re-radiated later.”

The parts of car parks not suitable for living can also be re-purposed, he says.

"All that other space in the car park, we can use for facilities for the people living there and also make them publicly available, which can subsidise the cost of what you're putting in there.

“So, I'm thinking here about laundries, storage, bookable guest spaces, bookable gathering spaces, commercially rentable spaces, maker spaces, co working spaces, all of that kind of thing.”

The owners of carparks are looking closely at the economics, he says.

“I have a private office in a quite upmarket apartment building in Auckland. When it was built in the ‘90s, those car parks were going for $100,000 each, now it's half empty. When I go into the car park, whether it's evening, day, weekend, holidays, whatever, it’s half empty.”

While retrofitting costs, it remains much cheaper than building anew, he says.

A converted car park in Melbourne is even using the roof space for an urban farm, he says.

“We’ve got all that concrete, we can start greening our cities collecting water, collecting sunlight.”

Nor are New Zealand’s seismic challenges an obstacle, McKay says.  

“You can stiffen them up pretty easily.”