Firmly planted on a steep and rocky slope in  Sydney’s   Palm Beach peninsula, the  stilted   ‘Balmy Palmy’  house   by  CplusC Architectural Workshop  celebrates the pleasures of modesty and simple life. The practice was invited to build the residence for a semi-retired couple, their three teenage children, and friends. After 20 years away from their home of Sydney, the clients wanted to embrace the local landscape on their bushland site. They envisioned a modest, compact home that blends with the surrounding trees and where they could recharge in the canopy among sunlight, foliage, and birdsong.

With a tight budget, the proposed construction system needed to be quick to assemble and repetitive to minimize supervisor site visits, requests for information (RFIs) to the architectural team, and on-site labor costs. The house also needed to be easy to maintain for the visiting owners.

Initially a vacant land, some 40 kilometers from the center of Sydney, the site presented its own challenges. To start, the lack of stable subsoil on a steep bushland slope was seen as a geotechnical landslide risk. The structure needed to be either excavated into rock or built on concrete pier footings drilled into Hawkesbury sandstone strata. It must also share space with many mature trees, notably an imposing council-protected Port Jackson fig tree perched on the rocky escarpment at the southern side of the site. 

‘There’s always a temptation at such a scenic site to build something monumental to guzzle up the views, often requiring tree lopping, excavation, rock sawing, and extensive retaining wall construction. In this case, the vision was to keep the house modest, unassuming, and receptive to its environment – a place to get away and engage with the landscape, native flora and fauna, the sky, and the ocean. Achieving this within the tight budget on the steep, rocky bushland site would require innovative construction methods to reduce complexity, construction time, and the need for regular site visits,’  writes the team at CplusC Architectural Workshop .

With that said, the architects proposed a simple timber structure floating above the steep land. Oversized hardwood timber columns and beams (290x45cm) contrast the thin, lightweight roof and stilt legs. Extensive outdoor decking connects all the spaces of the home and the different areas for sitting, relaxing, and gathering. People can lie suspended in the treetops and drink in the canopy from a cargo net bay.

Thanks to a ‘Meccano set’ design, it took less than a year to build ‘Balmy Palmy’. CplusC’s builders simply assembled all the pre-fabricated components that were delivered straight to the site. This included joinery, doors, windows, structural members, and paneling. Specifically, the construction features a partially pre-fabricated system with three-axis steel nodes that function as connectors. The timber posts and beams slot into the nodes and are bolted in place. A simple gridded system makes construction both straightforward and robust.

A simple, predictable way to build, the Meccano set approach comes with some risk. With all components pre-fabricated in advance based on CplusC drawings, there was no site measure to confirm dimensions during the build. The risk was that they might not fit together perfectly at assembly time. ‘ For CplusC, it was a calculated risk because we trust our team. Accountable end to end for design and build; we were confident we could work to the exactitude needed. In the end, it all came together exactly as planned,’  explains the practice.

‘Our team collaborated closely with the plumber and electrician to enable near invisibility of services, concealing pipes and cabling within the steel rectangular hollow sections (RHSs) of the construction. Perched high on the escarpment, the house welcomes visitors coming up the slope with a view of its corrugated iron underside, unmarred by pipes and cables.’

Furthermore, the centerpiece of the entrance, a massive metal spiral staircase fabricated as one piece, required a crane and all hands on deck to install. ‘ The spiral staircase installation had to be undertaken with great care as a major tree limb was in the path of its installation. We craned it in, then screwed it around the tree branch using the spiral to our advantage. We used our 3D model of the tree to plan how we would do this without damaging the tree. In complex construction challenges like this, it helps to be one team. Your architect and builder need to be thinking like each other. It was still a delicate operation, and let’s just say there were some tense moments when it was dangling from a 100-tonne crane 35 meters in the air,’  continues CPlusC. 

Ascending the stone stairs and spiral staircase of the ‘Balmy Palmy’ house, owners enter a secluded space suffused with light and leaves and open to the air. With a soundscape of bird calls, it’s like being in a treehouse. Glimpses of the beach, jetty, and Pittwater village shift behind foliage. The kitchen, living room, bathroom, and two bedrooms are stacked along the outward-looking building. With no hallway, it seems as if one is in nature every time one leaves a room.

Most of the house’s entertaining, relaxing, and gathering spaces are set outside, open to the air to give a peaceful holiday feel. A cargo net holding up to 900 kilograms extends the living area out into the air with a place for people to lounge and enjoy the view. Meanwhile, airy gridded mesh screens and webbing keep the cockatoos out and let light in, throwing intricate shadow patterns that transform through the day. The coastal breezes from Pittwater play through the living area thanks to large sliding doors and highlight louvers. Roller blinds can be closed for privacy.

Tech-wise, everything from the lights, locks, and ceiling fans to security can be controlled remotely on a smartphone via a FIBARO system. This lets the owners manage the home simply from their primary residence – or anywhere they travel. In addition, an automated irrigation system keeps the garden thriving.

Moving on to material selection, Blackbutt hardwood beams and columns and the spotted gum internal wall lining in ‘Balmy Palmy’ harmonize with the protected Pittwater spotted gum forest all around. In keeping with the setting, the ceiling and roof sheeting are made from galvanized iron, a traditional material for Australian bush homes.

The outdoor flooring is made from low-maintenance fiber-reinforced plastic (FRP); in an airy pale green that echoes the eucalypt tones, it provides the necessary privacy and security to the bedrooms. With a porous grid structure, bushland grit and rainwater fall through the holes, reducing the need to spend getaway time sweeping. And unlike timber decking, FRP is weatherproof, so oiling every five years isn’t required.

At night, LED strip lighting turns the home into an alluring lantern box. Glowing through the holes in the FRP, it emphasizes the gridded superstructure to elegant effect.

The project has low embodied energy for several reasons. A big one is the decision not to excavate. With the innovative and lightweight Meccano set design, CplusC significantly reduced the need for energy-intensive steel in favor of low-embodied-energy timber. With all the components designed and created offsite, there were fewer material deliveries and waste pickups to the site. Builders, architects, and project managers also traveled there less because of the simple construction.

The house is environmentally aware in other ways. It is carefully oriented to bring direct sunlight inside in all seasons. Large sliding doors and highlight louvers provide cross-ventilation; four Haiku ceiling fans reduce the need for air conditioning, with one in the kitchen/dining space, one in the living room, and one in each of the bedrooms. Even more, a Tesla car charger at the base of the stairs supports electric vehicles.

Finally, the house conserves water with all fittings meeting strict AAA rating flow rates. A rainwater tank captures water for use in bathrooms and irrigation systems. Supply to plants is adjusted automatically based on weather conditions. Although rooftop solar panels were considered, the site is heavily shaded year-round by the beautiful mature canopies, so they were ruled out.

image © Renata Dominik 

site area: 1m136 sqm 

floor area: 94.2 sqm (internal) , 55.1 sqm (external)

lead architect and builder: Clinton Cole 

project architects: Carmen Chan, Hayden Co’burn

foremen: Barry Bradley,  Nathan Krstevski

consultants: ROR Consulting Engineers, Urban Arbor – Arborist, Damian O’Toole Town Planning, QS Plus – Quantity Surveyors,  Witt Engineering,  Hill and Blume Consulting Surveyors,  Elite Survey,  Building Certification Approvals (BCA)

subcontractors: D2E Electrical, JHG Plumbing, Tenze Engineering, Flash Metal Roofing Pty Ltd, Sydney Kitchen Co Pty Ltd (SKC), Balmain Village Glass, Windoor 

photography: Murray Fredericks, Michael Lassman, Renata Dominik

spotted gum plywood: Big River Group

joinery (doors, drawer fronts): Laminex

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