Sustainable House Day, Collaroy, NSW

We set out to create a family home that was both sustainable and contemporary at the same time. To achieve this, we restored the original 1930’s beach house and added a modern extension to the rear, incorporating passive solar design elements.

Designer/Builder: Project was both designed and built by Luke Constructions (NSW) P/L

Climatic Zone: Warm summer/cool winter

Unique Sustainable Elements featured in this home

Orientation
New extension sited on southern boundary and orientated N-NW to take advantage of passive solar design elements. Summer sun is kept out, however winter sun is allowed to penetrate deep into the living area, warming the thermal mass in the concrete floors acting as a heat sink and reducing the diurnal temperatures.

Water Harvesting Systems
Installed a 9000l poly rain tank under the deck, fitted with first flush diverters and a ‘Rainbank’ for mains backup when required. Rain tank services internal toilets, laundry, outdoor shower, gardens and water feature.
Stormwater over flows to an absorption pit in the rear yard which in turn feeds the garden.
Manual greywater diversion system in place from laundry to garden.

Special Garden Features
The front garden has been planted with mainly indigenous plants that require no additional watering. Rear garden is a combination of indigenous plantings, deciduous trees for solar control and permaculture-style garden, complete with chickens and a vegie garden.

External Walls
The construction of the existing house is weatherboard while the extension is reverse masonry veneer, consisting of Hebel Powerpanels on a timber frame, sisalation and external cladding of Weathertex weatherboards to match the existing house. All external walls have been heavily insulated, with a combination of concertina foil batts and bulk insulation (depending on the orientation).

Internal Walls
R1.5 Sound insulation has been used on all internal walls where possible. Low-VOC paints have been used.

Roof
The original terracotta tiles were left on the existing roof, with salvaged tiles sourced for the garage to match. Extension has a Colourbond roof in the lightest colour that council allows with a pitch of 13 for maximum solar control. Insulation consists of R3.0 bulk in the ceiling cavity as well as concertina foil batts between rafters.

Floor
Polished concrete floors with 25% recycled content used in the extension with water-based sealant and foilboard insulation. Recycled floorboards used in original house to match existing where necessary with tung oil finish.
Deck is made from recycled jarrah.

Window Treatments
Cedar-framed, double glazing units with low-e internal pane and weather-seals all around were used throughout the extension. New windows are protected with large calculated eaves and existing windows are protected with a second hood/eave.
Large shade sail is erected during hotter months over deck and deciduous trees are used on east and west elevations for solar control.

Heating & Cooling
All rooms fitted with ceiling fans however no additional cooling is required as all openings are sited to take advantage of cooling sea breezes and cross ventilation.
Heating by slow combustion wood fire using salvaged timber only. In-slab heating is fitted however not used by owners.

Water Heating
Solar hot water heating – Endless Evacuated Tube split system with 315l s/steel tank and electric booster (gas booster to be retrofitted when funds permit).

Electricity Generation
Grid connected PV’s are to be fitted when funds permit.