The Limestone House in the inner Melbourne suburb of Toorak is a home unlike any other in Australia. John Wardle Architects took guidance from Living Building Challenge and Passivhaus principles to design the contemporary home. Built with robust natural materials and designed to ensure the house will generate more energy than it will consume, the house is one of the greenest addresses in Australia.

Specified for its beauty, locality and certification, Reclaimed Tasmanian Oak was used for the interiors in beautiful contrast to the home’s namesake limestone material. The project took over four years to conceptualise, carefully craft and then complete, finally welcoming its residents at the start of 2020.

An environmental agenda

Approached by the client with the request to create the most sustainable house in Australia, John Wardle Architects worked with an energy engineer at the start of the project, both agreeing on using the Living Building Challenge and Passivhaus as guides to make the house as green as possible. While the Living Building Challenge is a certification and sustainability building program that focuses on achieving optimal environmental solutions for the built environment, Passivhaus certification looks at a building’s energy efficiency and comfort.

Working within just one of these certification agendas is highly challenging; by using two, the architects could ensure the home would be providing more energy than it would be using, and its materials would be chemical-free, sustainable and local. Reclaimed Tasmanian Oak was specified for all of these reasons.

Reclaimed and brought to life

Reclaimed Tasmanian Oak is drawn up from the depths of Tasmania’s Lake Pieman using state-of-the-art technology. Thirty years ago, Hydro Tasmania flooded forests on Tasmania’s west coast to create water storage for energy production. In those hydroelectric dams, forests of 200-1000 year-old trees are still standing, submerged beneath the water. Thanks to innovative harvesting and processing methods, this valuable timber is now being reclaimed from the depths.

The timber was chosen for being quality assured and sustainably salvaged, John Wardle Architects associate principal Diego Bekinschtein explained.

“We needed the timber to be certified and have chain of custody, so this timber was an excellent option. Coming from the lake, the timber is in pristine condition with some beautiful and interesting colour variants compared to other Australian hardwoods. We loved the tonality of it; it created a beautiful offset to the Mt Gambier stone,” says Bekinschtein.

Used extensively on the ground floor of the home, Reclaimed Tasmanian Oak was chosen for the dining room as a ceiling lining to create a space encapsulated by the warmth of timber. Mirroring the ceiling, a custom dining table was made from the same timber. In addition, Reclaimed Tasmanian Oak was also used for the joinery, kitchen cabinetry, the study lining and the feature two-storey bookshelf at the home’s entry. Creating a slightly different feel on the first floor, the Reclaimed Tasmanian Oak timber stairs lead the home’s inhabitants to the second level where the timber can be found on the floor and bespoke joinery items.

Going green and staying green

While the timber was selected for its unique beauty, it also met other project ambitions.

“There’s a lovely story to the Reclaimed Tasmanian Oak. It’s both a local product and has low embodied carbon, making it a fantastic building material for the project. The timber submerged in the water seems to have also given the timber a unique colour tone,” Bekinschtein said.

“This project has shifted our mindset towards finding local materials where possible. In doing so, we have found some unique natural materials and products as well as talented local fabricators and makers. In doing this, we are supporting local industries and economies and bringing to our project an original and local flavour,” he noted.

While the Limestone House project was driven by an environmental agenda, Bekinschtein added that John Wardle Architects are working towards making all their buildings Net Zero carbon across all project sectors.

“Whether government led or not, we have to continue meeting the current environmental challenges head on. Our industry must play a leading role in this and it’s our job as designers to guide our clients towards better outcomes.”