This Energy-Efficient Prefab Is One Family’s Weekend Retreat by the Beach

This weekend home south of Sydney is more than just an escape for architect Hannah Tribe and her family. Situated at the edge of Royal National Park in the beachside hamlet of Bundeena, the design by Hannah, principal and founder of Tribe Studio Architects, is also a prototype for a new kind of kit home.

Looking at it from the street, the roughly 540-square-foot design presents itself modestly enough. Its minimalist timber-clad exterior nods to local vernacular, keeping with fishing cottages prevalent in the region that stand in large gardens with their rectilinear forms. Hannah’s innovations—and this is where the Bundeena home parts ways with the buildings of yore—are primarily concerned with economy of materials, energy efficiency, and sustainability, which allow the design to be replicated affordably and with ease in a variety of settings.

Everything relies on a "strict mathematic logic," says Hannah. Although she doesn’t dive into the numbers, the design starts with a concrete slab, and a modular timber frame that rises roughly 17 feet without the support of structural steel. Hannah could have expanded the home’s tight footprint and added a second level to capture water views, but that would have betrayed the area’s aesthetics.

"We could have had glorious views from a second story," Hannah explains. "However, we felt that reinforcing the local vernacular of single story timber cottages was important, and that an introspective garden diagram was preferable to outward looking in this context."

A second level would have also worked against Hannah’s initial concept, she says. And with a single level, it meant she could focus on energy efficiency.

Passive heating and cooling are achieved through the thermal mass of the concrete slab, and by siting the house to allow breezes to flow through its floor-to-ceiling sliders. Windows facing east, north, and west feature adjustable shading to reduce solar gain, while ceiling fans in the bedrooms provide a little extra airflow. All windows are double glazed, and the walls, although lightweight, are heavily insulated.

An extensive 5-kW photovoltaic array attached to the roof provides energy to the home, while a rainwater recycling system harvests water for the bathrooms, washing machine, and a garden irrigation system.

Hannah also made an effort to choose recycled materials and plantation timbers, and low- or no-VOC paints and finishes. The home’s water is heated with solar, and energy-efficient LED lighting runs throughout.

In plan, the U-shaped home wraps around a sunny central courtyard that faces a rear garden to the north. Inside are two adult bedrooms, and a kids’ room with beds and built-in sofas can sleep up to six. Instead of a mudroom, a laundry-and-bathroom combo in the entry is "a deliberate sand trap" for beach towels, wetsuits, and shoes—an appropriate substitute given the home is sited just 350 feet from the beach.

All in, the family-friendly design can host 12 people, "including lots of kids and dogs," says Hannah. The home’s full-height doors create an indoor/outdoor connection between the garden, the living spaces, and the interior courtyard. It’s also designed to be sturdy enough to accommodate the family’s sporty leisure activities, and "to withstand the salt and sand," as Hannah puts it. "[We do] lots of swimming and paddle boarding and kayaking and walking in the bush."

By putting the home on a slab, Hannah has created a stepless design, allowing her to eventually age in place or accommodate guests with limited mobility. "This house is an attempt to achieve a high level of architectural and sustainable outcomes at a low cost," says Hannah. "It is an experiment in delivering a more thoughtful kit home."

More from Tribe Studio Architects:

This 1930s Home in Sydney Was Preserved in the Front and Updated in the Back

Project Credits:

Architect of Record: Tribe Studio Architects / @tribestudio_

Builder/General Contractor: Ballast Construction + George Payne

Structural Engineer: Cantilever

Landscaping: Christopher Owen / @christopher_owen_

Photography: Katherine Lu / @_katlu

Artwork:  Gemma Smith