Residents in Ballybough House have long complained that their homes are blighted by mould and damp.
Now, Dublin City Council has ambitious plans to transform the flat complex, which was built in 1938 and designed by architect Herbert Simms.
Rather than pull down the protected structure with 111 homes, and rebuild, though, the council is planning a “deep retrofit”, to bring it up to modern standards for insulation and energy, with a B1 rating.
At a meeting of the council’s environment committee last Wednesday, City Architect Ali Grehan outlined plans for a pilot project for retrofitting the complex.
There has been a lot of discussion about what the council should be doing with its flat complexes that are protected structures, Grehan said. “They are important to the city’s identity.”
At this and other locations, Dublin City Council has also started to examine the overall environmental impact of demolishing and rebuilding old complexes, as opposed to refurbishing them.
The Pilot
Dublin City Council plans to knock two of the existing flats in Ballybough House together to create one larger home, as part of the pilot.
They’ll then carry out a deep retrofit, including insulating internal walls with cork-based lime plaster, replacing the windows and installing heat pumps in place of the gas heating.
“The city council has a lot of expertise in deep retrofit,” said Grehan. They brought existing homes in Dolphin House up to an A3 standard, she says.
The challenge is to figure out whether a deep retrofit will work on such an old building, she says.
If the pilot is successful, the council will retrofit the whole complex of 111 homes. They could potentially create a template for retrofitting protected structures that can then be used by other local authorities too, she says.
“We can help figure out, in terms of a national strategy, how you can deep-retrofit every house in the country, which is the requirement by 2050,” she says.
The Irish government’s Climate Action Plan 2019 says Ireland will “support the ambition emerging within the European Union to achieve a net zero target by 2050”.
Part of this effort, it says, will be to “Design policy to get circa 500,000 existing homes to upgrade to B2 Building Energy Rating (BER) and 400,000 to install heat pumps.”
At the environment committee meeting, Robert Moss of An Taisce asked how much the heat pumps would cost, what the total cost of the retrofit would be and whether the heat pumps would provide households with enough heat, once the gas heating system is taken out.
Grehan said the council is doing the pilot project in order to get some of those questions answered. She’ll report back at the next committee meeting with more details, she said.
A Dublin City Council spokesperson said they do not yet know the costs of retrofitting the homes or when the pilot project will commence.
Will It Work?
“Apartment blocks are inherently efficient so it is not like retrofitting a period house,” says Pat Barry, the chief executive of the Irish Green Building Council.
That’s because a typical apartment shares its ceiling and its floor with other apartments so less heat escapes than with a house.
“If you put breathable insulation on the inside you will halve the heat loss through the walls,” he says.
Dampness is a major problem in Ballybough House, but that can usually be fully eradicated, too, says Barry.
Multiple factors can cause dampness: poor maintenance, inadequate ventilation, or porous brick.
“But if you take a holistic approach to insulation, make sure there are no leaks, treat external walls if it is porous brick”, you should be able to fully eradicate the damp problem, Barry says.
To Demolish or Refurbish
There are some complexes where it makes sense to refurbish and retrofit, and others where it’s best to demolish and rebuild, Grehan says. Each has to be assessed and examined, case by case.
Barry of the Irish Green Building Council, says that it is generally preferable to renovate apartment buildings if possible. “The environmental impacts of demolition and rebuild are huge and particularly at the moment we need to reduce our carbon rapidly,” he says.
Sometimes, if a site is in a good location with public transport links, and is very underutilised, there can be an argument for rebuilding it a lot bigger, Barry says.
Constructing a new building creates around half a ton of carbon per square metre, he says. The carbon is generated through the quarrying and mining of materials, and especially through the manufacture of cement. So “a concrete structure has a huge environmental impact”, he says.
New buildings are achieving excellent energy savings, but the “embodied carbon” in a new build is likely to outweigh those savings, meaning that the new build is actually worse for the environment, he says.
“Even if you can’t achieve the same level of efficiency as you would with a new building you can considerably reduce the heat loss from an old building,” Barry says.
Embodied Carbon
Embodied carbon is the carbon dioxide emitted during the manufacture, transport and construction of building materials, as well as in the demolition of that building.
Green Party Councillor Michael Pidgeon, who chairs the environment committee, says it’s an important concept to keep in mind.
“It allows you to see that knocking a building, to rebuild a new one for energy efficiency reasons, often isn’t as great an idea as it seems, because the energy used in the construction is huge,” he says.
It is the same with a car, he says. Perhaps contrary to popular belief, it is not always better to switch to an electric car, because car manufacturing is very energy-intensive.
“In some cases, it is better to drive a car until it is done, especially if you don’t do a lot of journeys,” he says.
Until now, there has been a preference in Dublin City Council for demolition and rebuild rather than refurbishment, and this may have been influenced by the funding streams that were available, Pidgeon says.
Also, many regeneration projects where complexes are demolished result in an increase in homes – although not all. By contrast, refurbishment works often end with fewer homes than they began with, as in Ballybough House, where the council are knocking two flats into one to create a modern apartment.
The Department of Housing does fund refurbishment works, but “they are understandably driven by wanting to increase the number of units”, says Pidgeon.
The council has started taking into account “embodied carbon” when weighing up whether to demolish or refurbish housing complexes, says Grehan. That is going beyond what it is obliged to do in the current regulations, she says.
It is carrying out a research project on a site in Dominick Street too, assessing the embodied carbon in four possible approaches to an existing complex and a neighbouring site they own.
Barry says that the city should be “maximising what we have and improvising”.
“In 2020, we have just 10 years to avoid catastrophic climate change, so we need to cut our levels of construction,” he says.