North Avoca Studio

Top Deck

Owner, Tony Palmer, says that when he and wife Danielle bought the Central Coast property as a holiday house, he had an inkling that they might one day take more permanent advantage of the panoramic view over the suburb and South Pacific Ocean from the site’s steeply sloping rear border.

After making the move to North Avoca as a full-time home, and with both Tony and Danielle working from home in creative industries, they soon found need to emancipate house from office.

“I had a little office tucked under the house but it was like a shoebox. It had no aspect and was hot in summer and pretty horrible in winter. Before contacting Matt Thitchener, I was talking to agents about buying office space. The completed studio ended up costing about the same as a small office in Gosford, but I’m so glad we did it this way. Building a studio specific to our needs has so many advantages.

Did he ever think such an impressive and substantial architectural achievement was possible on the site? “No, we knew the challenges we faced with such a heavily sloped block. And with only 900mm-wide access, we had no ability to bring machinery onto the hill. So I went into it knowing the idea might not be feasible. Luckily, Matt saw it as a challenge that could be solved by getting it up off the ground and into the air.”

Matt Thitchener concurs. “I don’t mind difficult sites because it drives the creativity and guides the outcome,” says Thitchener. “My father is the engineer for this project and I had worked for him previously, before I got into architecture. We always liked pushing cantilevers and trying to do interesting things, structurally. I’m always looking to do something clever and sublime.”

Architect and client were pondering solutions when the core idea was born of a ‘box’ resting its back on an off-form elevated concrete beam, supported in the middle by a stilt frame made from structural steel. But first, they had to hit rock.

Initial signs from the site geotechnical survey indicated bedrock might be only a few metres away - “I think they hit some floating rocks,” says Palmer - but we eventually found it at 6-7.5 metres below ground level.

All four piers had to be dug out by hand, with bucket and spade. “We had two guys and they were so far down we lost sight of them,” says Palmer. “There’s basically a double-axle truck’s-worth of concrete - 6 cubic metres - in each pier.”

Knowing that such effort and expense was a possibility, Thitchener adapted his design early to minimise the number of piers necessary and devised the structural supports, or piloti, made from 89.9mm circular hollow section (CHS) steel. “The piloti were always going to be made from steel. It’s the natural choice,” he says. “Once you reach a certain span-size it doesn’t make any sense to attempt construction with other materials.

“Size-wise, you aren’t going to get the slenderness that steel has out of timber, and concrete would have been just too heavy.”

Thitchener put his steel piloti design through the engineering modelling process and discovered there was the potential for the CHS to be thinner. “But we decided that would look a little bit too thin. Aesthetically, I preferred the wider 89.9mm-diameter selected, for a stronger appearance. That also allowed for more room to fit all the plates and bolts at the end.

”The CHS piloti also provide cross-bracing for the overall structure, resulting in a clean aesthetic. “Had we just used simple vertical columns, we would still have needed lateral cross-bracing in between them and it would have been much busier underneath,” he says. “It was just a better way of doing it, structurally, for the rigidity of the building and was so much simpler in construction. We were basically building a small space-frame.”

Sitting atop each pier footing is a circular 200mm-thick custom-made steel base plate with cleats connecting the CHS piloti. Another cleat at the top of each piloti connects it to one of three main steel floor bearers running front-to-back. The floor bearers are 310mm universal beams concealed within the floor space - one running through the middle and one under either side of the building. These are connected by 89.9mm CHS and 180mm UB tie beams that span side-to-side. All the connections are pinned together.

Sitting atop the universal floor beams are vertical columns made from rectangular hollow section (RHS) steel and square hollow section (SHS) steel that support the steel roof structure and the cantilevered awnings. A long-span universal beam supports the roof trusses over the sliding doors, and another smaller universal beam supports the roof trusses at the heel end.

All structural steel was prefabricated for speed-of-installation and craned onto site. “We had to lift from the street, up over the powerlines and the house, to start building our working platform,” says Thitchener. “In a single day, all the scaffolding was erected and the main structural steel  frame bolted together.”

Palmer says he was immediately taken with the view from the in-construction studio. “Pretty much as soon as the frame went up and a floor was on, I walked out onto that platform and thought, ‘Wow!’. I knew we had something special.”

The building envelope is completed with roofing made from COLORBOND^® Ultra steel in LYSAGHT TRIMDEK^® profile, in the colour Windspray^®. The LYSAGHT TRIMDEK^® profile was chosen for its low (two degree) pitch for gathering rainwater - used to irrigate the fern garden planted under the studio - and the colour Windspray^® for its lower solar absorptance than the darker-coloured Monument^®.

Virtually the entire 60 square-metre roof is covered in solar panels which generate enough power to comfortably run the studio and also the main residence, with excess electricity being stored in a battery.

The studio is accessed via a detached industrial staircase made from galvanised steel, which ties in visually with the CHS piloti. Ascending, the intricate geometries of the piloti come sharply into focus, as does the meticulous detailing of the soffit and southern wall cladding made from COLORBOND^® Ultra steel in LYSAGHT SPANDEK^® profile, in the colour Monument^®. Deliberately windowless, the south-west wall creates a screen to the view that is broken only via the front door. “The outside surfaces are hard – quite raw and masculine,” says Palmer. “Contrastingly, the interior with its sheer curtains and diffused lighting, is quite soft, airy and feminine– which is just as well because my wife shares the space with me.”

Wall-to-wall and floor-to-ceiling sliding glass doors in the south-east wall - along with commercial bi-fold windows which span the entire north-east wall - open up the studio up and invite the outside in.

Floating ethereally in its panoramic coastal setting, the North Avoca Studio might at first glance appear a simple combination of two key elements. A closer inspection reveals a study in daring design and elegant execution, the result of which is greater than the sum of its parts.

How do architect and owners feel now the project is complete? “So much went into this project that no singular particular element stands out,” Thitchener says. “It’s a lot of little things that have come together to make it a successful whole. I’m always excited to see it in the flesh though. I get such a good feeling when I visit. I look at it and think: ‘I did that!’.”

The building imparts a similar feeling in Palmer. “It really has exceeded all our expectations,” he says. “Functionally, it has met our lifestyle needs but beyond that there is such a wonderful feeling when you walk through the door. I never thought it would be so tangible and rewarding.

“Whatever could be going on outside, when I come up here it’s just serenity. Everything just feels right with the world. I feel complete.”

Note:

*For details on steel roofing and walling product selection, please refer to BlueScope Technical Bulletin guides TB 01A and TB 01B or call BlueScope on 1800 753 658.