Innovations

MCHP Architects and our client see design flexibility and building longevity as an important issue for sustainability of buildings. This project has been created as a four bedroom house, for a family of two adults and two teenage children, set up as two modules. This concept also allowed for half of the house to be easily adjusted and rented out when the children moved out, while the parents remained in their half of the house. This would provide an income stream allowing the owners to remain in the locality they wish to live, while having financial and lifestyle sustainability. It would also allow the potential of one of the children to temporarily move back in with a young family while becoming financially secure to purchase their own house, or potentially a grandparent to move in.

All living areas and two bedrooms have direct northern exposure, while the other two bedrooms also have northern exposure when their large sliding door is open. Cross ventilation is created throughout the house. The various areas of the house can be closed off, should localized heating be required when there is an extreme cold. The front entry, facing south, has an airlock arrangement to also assist with minimizing heat loss. To minimize heat loss through windows, double glazing has been utilized and seals are provided at doors and windows. The house has been designed to consider draped curtains at the planning stage rather than a design afterthought. Thermal mass is provided with the concrete slab absorbing the warmth of the winter sun and radiating it into the house at night. Insulation will be installed throughout with R 3.5 roof insulation and R 2.0 wall insulation.

The building design including window locations and fixed eaves locations have been carefully designed to allow winter sun and control summer sun. The pergola over the terrace provides weather protection and solar control.

The building incorporates a 2kW photovoltaic system and solar hot water heating. Energy efficient light fittings, LEDs and compact fluorescent lights, shall be installed. Appliances have been chosen for maximum energy efficiency. Rain water storage shall be used for toilets, washing machine, gardens and car washing and high water efficiency fixtures have been selected. Clothes drying areas positioned discreetly to encourage outdoor drying.

Low embodied energy of materials has been considered with aluminium used only in the vergola pergola system and steelwork kept to the roof sheeting, gutters, downpipes and the rain water tanks. The health of the building occupants has been carefully considered through the building design, flexibility, ease of access and building use, the interaction of inside and outside, passive solar design and easily cleaned materials and finishes.

Affordability

We wanted to produce a house which is affordable to build and maintain. This was done using simple construction, building form and spans, efficient planning, building to standardized sizes and lightweight yet durable and low maintenance claddings and finishes.

Utilising government grants for environmental initiatives helped to achieve long term energy savings at a reduced cost. Ongoing cost savings come from solar hot water heating, no air conditioning, use of rain water storage, water saving fixtures, energy efficient appliances and lighting and educating the owner on using the house effectively.

The ability of this project to be adapted to into two separate living units provides a potential future income source and the flexibility of its design has an important impact on the financial sustainability of this building.

Lightweight Materials Used

Wall Cladding – James Hardie Scyon Matrix & HardiPanel.
Roof – Colorbond roof sheeting and guttering.
Structure – Plantation pine timber framing.
Front Fencing, Feature Walls and Screens – Futurewood “Newtech Enviroslat” a low maintenance slat material consisting of a mix of recycled plastics and reconstituted timber offcuts.

Material Rationale

Cladding – James Hardie Scyon Matrix and HardiPanel have been selected for their appearance, low maintenance, long lifespan and the inert nature of the product which does not warp or suffer damage in the environment.
Lightweight Structure – this was selected for affordability, speed of construction, less trades on site, less embodied energy and that it does not lose the floor space of the thicker brick cavity walls. The frames and spans have been designed to keep the structure cost effective and not require steel framing.
Floor – a concrete slab has been used throughout, with a polished finish used for the living and bedroom areas.
Roof – the light coloured, Colorbond roof and guttering has been selected for its appearance, durability, low maintenance and light weight.

Project Team

David Cahill , Hubert Sawicki, Bashodha Rai