Originally published on Stuff.co.nz at 10:00am on 12 September, 2022
By Colleen Hawkes

You have to be passionate and dedicated to wait 12 years for the house of your dreams, but that’s what Margaret Stewart of Edgeware, Christchurch is doing.

Stewart and her family moved into this 1910 villa in early 2010, only to leave it again temporarily following the Christchurch earthquakes later that year and in February 2011.

The villa sustained considerable damage (“it was like a train hit”), and it shifted on the old piles, thanks to liquefaction – “every wall leaned in a different direction”. And while Stewart went through the tediously long process of making claims to the relevant authorities, dealing with disputes, family ill health and financial issues, the years slipped by.

Margaret Stewart stands outside her earthquake-damaged villa that is being retrofitted as a Superhome. The project has been in the planning for 12+ years. Image: JOHN KIRK-ANDERSON/STUFF

In hindsight, she says that time-lapse proved fortuitous, because she met engineer and high-performance housing consultant Damien McGill of The Healthy Home Cooperation in 2014.

McGill subsequently inspired Stewart to go the “whole hog” and rebuild the villa to Superhome near-passive house standards, with an airtight interior, mechanical ventilation, double glazing and superior insulation in the floors, walls and ceiling.

But it hasn’t been easy. “I have held on to my dream,” Stewart says. “So many people would have given up and the house would have ended up in landfill. But I’m not falling at the last hurdle – you have to keep going, and you know you’ll feel so proud of what you’re capable of doing.

Stewart is pictured with healthy home consultant Damien McGill who has inspired her to take the opportunity to upgrade to a low-energy home with better insulation, an airtight interior and mechanical ventilation. Image: JOHN KIRK-ANDERSON/STUFF

“Several people have asked me ‘why don’t you pull it down, and we’ll give you a new home’, and I’ve cried a few times when they’ve said that.”

Stewart had been living back at the house in its damaged state, but the family moved out in 2020, so the major repairs could start. “By then there were only three lights working in the entire house,” she says.

The work could hardly be more challenging – the whole house had to be moved, so work could begin on land remediation.

The original villa in Woodfield Street had a bay window and a large front porch, both of which are being reinstated. This photo was taken in 1953, but the villa dates back to 1910. Image: Supplied

As McGill, who has retrofitted his own older home, explains: “We demolished the rear of Margaret’s house, lifted it onto rails, and slid it to the back of her section to allow us to improve the ground, as there is nothing solid down below to put a resilient foundation onto.

“This ground improvement required driving 250mm diameter timber poles 5.4m long into the ground on a 0.9m triangular grid. Approximately 230 poles were driven and there will be more required when the sleepout is built. (We couldn’t do this work at the time as the house was in the way)”

McGill says a 300mm reinforced concrete foundation has been constructed on the piles to provide a new earthquake-resilient foundation for the home. The house is also higher above the ground to avoid potential floods – there has been serious flooding in the past.

The house was put on rails and rolled to the back of the section while 230 poles were driven 5.4m into the ground to provide the base for a 300mm-thick concrete foundation. Image: Supplied

The house was slid back on top of the concrete foundation that’s supported by 230 poles. Image: Supplied

House can be re-levelled easily in future if needed

“A feature of the foundation is the specification of ABI Piers’ re-levelable piles so that if there is another big one (earthquake), and the foundations settle again, which they shouldn’t, but if they do, it will be very easy to re-level the house again.”

Outside, weatherboards have been removed and where possible salvaged for future use. A layer of structural ply has been added as the bracing layer and rigid air barrier, before new timber cavity battens and new weatherboard cladding are fixed in place.

Nigel Colenso, director of Niche Projects, shows the adjustable piles that can be used to re-level the house if needed in the future. Image: JOHN KIRK-ANDERSON/STUFF

“Inside, the lath and plaster walls have been demolished, and Terra Lana wool insulation has been installed to insulate the walls and ceiling,” McGill says. “Pro Clima Intello has been used as the airtightness membrane. A 45mm insulated services cavity will be added before the final layer of plasterboard is fixed.”

NZ Foam has sprayed PUR foam under the floorboards and between the joists to super insulate and to make the old floorboards as airtight as possible.

Ventilation will be provided by a mechanical ventilation system with heat recovery installed in the attic. When completed, the house will have all new electrics, plumbing and drains.

Stewart decided to recycle the existing windows and reclaim some more to match the style of the house. She says it was important to maintain the character – she is replacing a large picture window with a bay window repurposed from a salvage yard, along with stained glass windows for some of the doors.

The windows have all been sent away to RetroDG for double glazing with low-e glass filled with argon gas.

“While this will improve the performance of the window itself, the frames won’t be as airtight as new PVC windows for instance, so this will detract from the overall performance of the home,” McGill says. “But as far as Margaret’s concerned, we also need to improve the way the home looks and keep the heritage appeal.”

McGill says when finished, the old villa won’t be a certified passive house, but it will have been given a new lease of life and from a healthy homes’ perspective, will be much more energy efficient than the new modern units that have recently gone in across the road.

“The project will prove that Healthy Renovation is a viable option in the modern low-carbon friendly world as we move towards 2050.”

In the meantime, Stewart is allowing herself the luxury of planning an exterior colour scheme. “The house will have a grey roof, white window joinery, black doors and blue-toned weatherboards. I will also be installing replica chimney pots, so it looks as it did. And I will have a picket fence at the front, and maybe along one side.

“The original houses in this street were all villas. There have been some rebuilds that are almost, but not quite replicas, and other new builds that are nothing like what was there before.

“My aim is to inspire other people (to retrofit) their old villas. They don’t need to knock their villas down. We need to hold on to our heritage architecture.”

The costs involved in this project are not available, as it involves insurance claims and a lot more work than a pure villa retrofit.

But the villa will be open for Superhome Tours on September 24 and 25, and there will be a chance for interested parties to talk to Margaret Stewart, Damien McGill and the suppliers. They will be giving talks on various aspects of the refurbishment.

  • Engineer and healthy homes consultant – Damien McGill of the Heathy Home Cooperation
  • Geotech – Landtech Consulting
  • Builder – Cornerstone Construction
  • Insulation – Terra Lana & NZ Foam
  • Membranes and tapes – Pro Clima
  • Subfloor piers – ABI Piers (Niche Projects)
  • Double glazing – RetroDG
  • Glass – Metro Performance Glass

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