Coopworth House

Accepting the Elements

Situated in a paddock at the far edge of Tasmania, there's nothing between this house and Antarctica except a few penguins. An incredibly robust material solution was therefore always going to be needed to withstand the unforgiving climate.

In the words of the architect, the winds on Bruny Island are "ferocious, some of the strongest in Australia", and the rain is "relentless". Add Bushfire Attack Level (BAL) compliance and a remote location to the list of constraints, and this was never going to be an easy build. Throw in a once-in-a-century pandemic, which locked the architect in Victoria for the duration, and the project's challenges take on Herculean proportions. And yet the Coopworth team pulled together, enthusiastic and unfazed, to deliver this contemporary country home which has exceeded all expectations and celebrates the versatility of steel.

The building's practical response to the weather and fire extremes is expressed in a resilient exterior shell, which, in an area where deliveries are limited by ferry access and country roads, needed to be made from an easily transportable material. Meanwhile, the design's aesthetic response to the site sought to complement the original agricultural sheds on the farm. Steel was fundamental to both solutions. "We needed something that is extremely hard wearing," explains architect Fiona Dunin, of FMD Architects. "We used COLORBOND^® steel because it's lightweight, easy to transport, highly durable, easy to install and the colour is a strong reference and direct connection to the existing red-lead shacks on the island. It was always going to be steel."

The need to limit penetrations on the roof to eliminate leaks and leaf build-up was an overriding functional concern that has contributed to the signature clean lines of the building. With extraneous elements stripped away, and gutters relocated to trenches in the ground, attention is focused on the pure geometry of the building. This geometry is further accentuated by pushing the pergola area to one side of the house rather than wrapping it around, so as not to obstruct views out from – or back to – the house.

"So, completely clad in steel means, in some ways, you're limited as to where you can hide things," says Singleton. "And so there's a lot of forethought right from the time you're digging your hole, essentially the whole way through to the finish, that you're always thinking about how that thing is going to look and how it's going to be finished at the end."

The pre-planning and documentation phase of the project was intensive and intensely cooperative despite the distance between FMD in Melbourne, In2Construction in Hobart and the builders on site – a number of whom opted to live on Bruny Island during construction and lockdown.

"There were probably 20 to 30 sheets of details on every single juncture, down to how those big sheets of glass come together and putting a capping made from COLORBOND^® steel on the edge of those," says Dunin. "All those little details – even the bin storage area was extremely detailed – nothing was left to chance. And so we don't tender jobs, we negotiate with the builder through the documentation phase. They can review the details with us, have a look at them, and then they get reviewed again on site. When the builder looked at them he had other ideas and then we'd rework them. They were probably re-worked two or three times with the builder, to get them right and still achieve the look that we wanted. It's a very collaborative process."

In particular the resolution of the junctions where steel meets glazing drew on all the knowledge of those generations of skill and the strong relationship between builder and fabricator, Central Roofing Supplies.

The structural steel elements of the build were more straightforward, using standard- sized SHS, PFC and UB members and predominantly bolted connections.

Internally, a large open-plan lounge-dining-kitchen area, which is flanked by two bedrooms, bathrooms and a small rear protected porch. The footprint of the house was kept compact for a number of reasons: to maximise arable land, minimise build cost and acknowledging that at most times there would only be two people using the house. Having said that, Coopworth would nonetheless need to occasionally accommodate an extended family. To avoid having to add bedrooms that would be used only once or twice a year, bunk beds are set into pocket walls and daybeds into the floor of the main living area, where space has been augmented and steel was called on to provide the structural strength required.

"Over the dining area is a very large span of roof that you can see and so that has some fairly substantial steel beams through there," says Dunin. "It had to be done in steel to get that span, most definitely."

Singleton agrees, citing further reasons for the decision to use steel. "Structurally, it gave us the ability to do long spans, so that long beam that's in the living room, it's holding up half of the roof load, essentially. It gave us that ability to go that long span without having a huge, big bulky member in there. If it was timber or LVL or something like that, or a glulam beam, the size of it would have been huge. So steel meant that we could do that economically."

While economics did not define this build – landscape and materiality are the lasting takeouts – it was nonetheless a concern owing to the expected time-cost associated with building in a more remote location. In the end, however, the project compared well financially.

The ongoing efficiency of the house has been addressed via a number of sustainability initiatives, resulting in a building consisting of double glazing, substantial insulation, LED lighting throughout, low VOC paints and local or recycled furniture. Recycled timber from the one of the owner's childhood family farm has been used in key furniture pieces such as the dining table and the kitchen island.

This is the third time that the clients have commissioned Dunin to create a home for them, so it's no surprise that their feedback is effusive: "FMD smashed the brief and created something super special," the clients said. Dunin is quick to deflect any individual praise and says the project is a reflection of an outstanding, resilient and collaborative effort across the project team which delivered a beautiful outcome in spite of the challenging and unique circumstances of the build.

Unable to see the project take shape in the flesh, she has since visited Coopworth and her favourite thing about the home is how it sits in the landscape and how the occupants can intimately experience the environment through the large expanse of windows in the open-plan living area.

"The glass basically butts right into the edge of the roof so when it rains; it's like a waterfall running down the glass. The thing with Bruny Island is you need to just accept the elements. It rains so much that you need to get used to it; we wanted to kind of embrace that so that you always feel the weather, you're not really sheltering from it, you're standing there with your arms wide open like Kate Winslet on the Titanic [laughs] embracing the weather. So, when it's rainy and you're sitting inside, you feel that rain, you're part of it. And when it's a sunny and peaceful day it's the most serene place in the world, it truly is."

Steel Details

A Technical Dive into Coopworth

Architect Fiona Dunin has a thing about triangles and it's an itch she hasn't yet fully scratched. "I think it's about the geometry and capturing light, and the way the angles work. So we follow the angles of the sun and for some reason that ends up being sculpted into triangular forms," says Dunin. "[But] the thing with triangles is they come to zero. There is no tolerance. Everything has to be perfect."

Working with triangles in steel – and in particular the junction between steel and glazing – presents its own set of considerations, as Dunin had explored on an earlier residential project, CLT House, featuring a dramatic saw-tooth roof made from COLORBOND^® steel with integrated windows to capture the changing light throughout the day. That experience informed the design of Coopworth.

The owners had imagined Coopworth as more of a weekender. However, it took on a new dimension during lockdown as a more permanent second residence.

As a result, they requested a mid-build change to include an operable window in the roof to allow more light and air into the second-level study space, to be able to more comfortably work from home in the future. Dunin proposed a triangular dormer window to meld with the overall aesthetics of the project, and the builder and fabricator rose to the challenge.

"How do we build that in so that it looks like it was always meant to be there and get some uniformity across the whole building? So how do we make a little ventilation flap, how do we make that open and close but also remain weathertight as that faces south and southwest, which is exposed to the roaring forties winds? The window had to be made watertight and all seemingly effortlessly with that whole minimalist idea, the flashings and all the elements that make it work."

As with the junction where the long glass wall meets the roof and where the absence of roof guttering to mask irregularities might otherwise be met with consternation if adequate planning was lacking, Singleton said this was counterbalanced by the ability to pull the sheets of COLORBOND^® steel in LYSAGHT CUSTOM ORB^® profile up and down to allow the fixing of the custom flashings and ember proofing as they were refined and manipulated during this dormer-design-on-the-hop process.

"When the glass came we managed to be able to get the glass in underneath the steel sheets without taking the sheets off, but then to fit the flashings and the ember-proofing, and all the other little bits of detailing that happened, that meant we were unzipping and zipping those steel sheets on and off. Definitely the ability to reuse the screws and screw holes, and steel is quite stable.

Custom flashings were manufactured from COLORBOND^® steel in the colour Terrain^®* by Central Roofing Supplies at their Hobart workshop and then transported to Bruny Island.

"It was an easy job from our perspective because Mark Thiessen [a member of the building team] is a good operator," says Garth Bealey of Central Roofing Supplies.

On a job like this, with transportation and time being clear constraints, those generations of skill and experience were essential and really came to the fore in the precision of the drawings and the accuracy of the finished products. These exacting fabrications respected not only the power of the elements, but also helped achieve the architect's vision for a form with powerfully clean lines.