Architectural engineering makes use of a difficult site
Construction waste is managed
High use of recycled and recyclable material
Location: Grandview Terrace, Earlville, Cairns, QLD, Australia
Year Completed: 2011
The home features a number of curved roof sections that fall strikingly well over vibrant walls of purple, wild moss and charcoal. The external face of the house hosts stunning banks of timber louvers and sweeping expanses of curved verandas on all sides. This home has been skilfully built with a focus on the tropics. Designed for a large extended family, this home is full of practical sustainable design features including recycled and plantation timbers.
Awards: HIA Australian Greensmart finalist 2012.
The block of land was vacant although every other block in the suburban neighbourhood had established homes. Investigation revealed it was a very difficult site. The majority of the land was part of a very steep slope that was also made up of uncontrolled fill. The owner builders had initial design ideas and the building designer and engineer developed the design to overcome the constraints.
The design required Cairns City Council planning approval as it exceeded the height allowable for a residential house at the rear. Although the home was not in an area that is part of the hill slopes code, the code was applied.
The house and landscaping design represents great sensitivity towards the visual amenity for neighbours.
A waste storage and collection area was provided on site and managed to limit overflow and illegal dumping. A separate waste bin or collection area was provided on site for construction waste that can be recycled. One of the risk management strategies included the development of a checklist to ensure accurate ordering and appropriate estimating of materials. Construction materials included the use of prefabricated roof trusses, cabinetry and sub floor steel foundations.
The land is situated on a ridge that has an elevated position of approximately 100m above sea level in the foothills of Earlville. The land has panoramic views over the city and Cairns Inlet to the north.
The area situated closest to the street front is flat and approximately 400 m². The northern area of land falls for 9m over the next approximately 16.5m and continues to slope steeply to the rear boundary of the lot. The front boundary of the lot faces south with some interrupted views. The western boundary of the lot is overshadowed by the adjoining property which is two storeys from a higher ground level than the subject land.
As the block is long and proportionately narrow, the house frontage is 13m at its widest point and approximately 39m in length. 19 metres of the house length spans over the slope equating to 62% of the house footprint. The height of the home from the ground on the northern elevation is 15.5m. This engineered solution makes previously un-usable land, usable.
To stabilise the slopes and create a visual screen to the building height on the rear elevation large trees are planted. There is a garden area with northern exposure available for herbs and vegetable gardening and composting. There are also bananas, pineapples, lemons, limes, passionfruit, mangos, avocado trees, native fruit trees and a macadamia nut tree planted.
The outstanding natural feature of the land is its panoramic view over Cairns and the inlet. Careful design has taken full advantage of this northerly aspect of the home.
The main living areas are located in the single storey structure constructed over the steep slope. This allows the flat land to be used for a double storey structure, outdoor lawn area, swimming pool, and entrance area and car accommodation.
The entrance area and southern elevation is angled to receive any south easterly prevailing breezes. The orientation of the house and use of the natural features of the land minimizes the impact of the sun on the walls of the house. Large eaves and roofed deck areas shade walls.
There are extensive outdoor living areas and openings to the home maximizing the prevailing breezes. The design takes advantage of air circulation through natural ventilation in active rooms. Ceiling fans and floor ventilation have been incorporated into the design. Vents have been designed to enable ventilation in the roof space to avoid dampness and mildew.
The design has many features that also promote access and useability for children and the elderly or disabled. There is a continuous level pathway from the street to the entrance and the doorway into the home has a level transition, landing and threshold and shelter from the weather. The wall framing in the bathrooms allows for future installation of grab rails and there are step free shower recesses. All internal doorways on the ground levels have a minimum clear width opening of 820mm and corridors are 1200mm wide.
The ground floor structure on the flat land area is rendered masonry block and the balance of the home is steel frame with timber wall and floor infill and fibre cement cladding. There are two main and two minor roof systems that are curved metal sheeting. Steel is fully recyclable and timber a natural carbon store.
Materials are locally sourced including the subfloor steel foundation, balustrade and stairs. Structural timber beams were all recycled from the local demolition yard. All other timber was sourced from sustainably managed forests. All custom doors and windows are locally sourced and decking is in part recycled timber and some recycled steel. The first level floors are bamboo.
The paint, decorative finishes, coatings, stains or transparent finishes, sealants and adhesives have been selected as they achieve a total VOC emission of 0.5 mg/m³ or less within seven days from application.
Thermal reflective insulation is used on the roof and in walls and additional bulk insulation used for air-conditioned zones and noise proofing.
Energy use is managed with an energy meter that is located in the main living area.
Air conditioning is only needed for a few weeks of the year and the home has an air conditioning zone that includes doors, walls or other features that allow groups of rooms to be closed off to create smaller spaces for cooling.
Ceiling fans are installed in living areas and bedrooms to reduce the need to operate air conditioning.
Compact fluorescent light bulbs, fluorescent tubes and LED lighting has been installed to 95% of the light fixtures. All fitted appliances are energy efficient.
A solar hot water system is installed as well as a 2 kWh photovoltaic system.
All toilets have a minimum 4 star WELS rating and all showers are fitted with a minimum 3 star WELS rated showerhead. All hand basins and sinks are fitted with minimum 4 Star rated tapware.
Rainwater is harvested and the 25,000 litre rainwater tank supplies water to the toilets, laundry and hot water system. It also supplies water for external uses and the garden.
Gardens have been designed to minimise water use and retain rain water in the garden area. Solar fountains and water features have been installed in the garden. Soil conditioners have been applied and mulch is kept at about 250mm. There is a selection of drought tolerant native plants and succulents planted.
The swimming pool has been designed to reduce reliance on potable water through a backwash reticulation and treatment system or cartridge filtration system or rainwater top up.
Living at Grandview feels like floating above the trees; in a sea of clouds and gentle breezes. The living area is bright and airy and the vast verandas are cool and restful. Grandview is our sanctuary, a happy marriage between resort lifestyle and practical living. Ian and Cate Teece
Base building architect/ designer: George Thirkell, Beachcomber Building Designs
Civil engineer (Site and traffic): George Thirkell, Beachcomber Building Designs
Structural engineer: George Thirkell, Beachcomber Building Designs
ESD consultant: Green at Heart
Energy efficiency rating consultant: Green at Heart
Green Star rating consultant: Green at Heart
Builder: IFCM Constructions: Ian Teece
Information and photos are supplied by the project owners and designers. The Tropical Green Building Network and James Cook University (the administrators) cannot guarantee the accuracy or authenticity of this content. Produced July 2014.