Consideration of Environmentally Sustainable Design (ESD) principles in a new Custom Home is essential for a successful outcome. In today’s climate the implementation of these principles is a fundamental responsibility of every architect. Recent changes in planning legislation are forcing changes to the way buildings are designed and built.
A combination of many factors leads to a successful, sustainable design outcome. Some of these considerations include:
- Thoughtful planning utilizing passive environmental design measures
- Energy efficiency and performance – use of solar power, adequate insulation, and reduction of a buildings energy consumption
- Responsible material selection – use of recycled timbers and other materials that involve smaller amounts of energy in their production.
- Storm water / Rainwater harvesting / Grey water treatment and reuse within and around the dwelling
Recent Projects
Sustainability Considerations
Material Selection
Sensible material selection and utilization of these materials in an efficient manner is crucial for real ESD and construction. Some materials are inherently unsustainable. Unfortunately there are many materials used in the modern building industry that cannot be reused and don’t break down once they are produced. A carpet tile, for instance, will last for 10,000 years in landfill, but only 6 years as carpet. This practice could best be described as ‘making landfill’ that is temporarily used as a ‘building material’.
Environmental damage associated with building materials when they are extracted and manufactured is also a major environmental issue. All building materials have an environmental load associated with their manufacture. Cement, the world’s most used building material, contributes considerable CO2 emissions in its production. 10 tonnes of raw material is required to be mined for every one tonne of cement produced. With steel 14 tonnes of iron ore are required for 1 tonne of steel produced. The materials used in the building industry already create a major environmental impact, even before they are placed in a building.
Reuse of building materials on site, employment of recycled resources, sourcing locally produced materials and specifying renewable materials are meaningful ways to reduce building waste.
Most of the material left over from building and demolition finds its way into the waste stream. Traditionally, the amount of building material going to landfill is around 30% of the total used in a job. Only 11% of this gets reused within the industry when it is collected for reuse or recycling. A good architect can design and detail a building to minimise waste from the building process. Designing to minimise waste and labour is a standard consideration when designing purely functional structures such as large freestanding factories. We include the principles of efficient material use and waste minimization in all our residential home designs.
Is Timber Sustainable?
The use of timber as a building material is, in a general sense, environmentally sustainable. However, many timber products including Southeast Asian rainforest timbers are gathered with little regard for the environment. The claim that some of these imported timbers are sourced from managed or renewable forests deserves a small amount of research. Australian plantation timbers and hardwoods from managed forests are preferable.
The newly implemented Australian Forestry Standard (visit website) intends to assure consumers that the Australian timber they buy comes from a forest that is sustainably managed. South Eastern forests in NSW are generally not clear-felled, and therefore have a more sustainable regime of management compared to the Hardwood forests of Victoria or Tasmania, where the majority of building material comes from clear-felled forests that are also used for wood chipping.
A principal objective for responsible design of environmentally friendly timber construction is to minimise life cycle energy consumption. Timber in lightweight construction is a superior material compared to manufactured material such as steel, concrete and masonry as it uses a comparatively small amount of non-renewable energy in its extraction and manufacture.
The ill-informed ESD advisor will argue that aluminium is a renewable material as it can be recycled. The fact is very little aluminum is recycled during demolition. The practice of aluminium smelting (refining the ore) consumes almost 30% of the total electricity consumption of the entire country each year. This total energy use comes from just two smelters.