Materials Use Development
The material use in both the Commercial Developments and Clarendon Residential business is substantial. Our new commercial office developments are being rating using Green Star which includes targets for reductions in the impact of materials use. For Clarendon, as material inputs represent approximately half of the cost of a house, there is a financial incentive to look at how we can reduce the material inputs into our homes.
Estimates of Materials use in Clarendon Business
For the first time we were able to estimate the materials use in Clarendon Residential's housing business. Using a standard Bill of Quantities (BoQ) for Clarendon single storey and double storey product, we estimated the materials use across Clarendon Homes nationwide.
This analysis produced some startling statistics and is helping to refine priorities. Priorities have been determined based on a combination of net impacts and our ability to effectively address them through design and by collaborating with suppliers. Our top 10 priorities for focus (and 2006/07 quantities) are as follows:
| Paint |
532,764L |
| Timber frames and trusses, pine internal timber (including mouldings) |
27,308m3 |
| Doors (entry and internal) |
38,522 (#) |
| Insulation (external walls and ceilings) |
563,503m2 |
| Bricks |
18,866,000 (#) |
| Standard roof titles |
400,619m2 |
| Bricklayers sand |
23,479T |
| PVC sewer pipe |
272,776m |
| Copper pipe |
89,150m |
| Concrete for slabs |
49,200m3 |
To put some of these figures into fathomable volumes, last year our housing business used enough paint to half fill a 50 metre municipal swimming pool, enough roof tiles to cover 80 football fields and 10,000 truckloads of concrete.
Other materials (and 2006/07 quantities) which will be focussed on in the future are:
| Steel |
1,732T |
| Windows |
26,265m2 |
| Laminated shower screens |
13,176m2 |
| Polished edge mirrors |
6,293m2 |
| Light points |
42,947 (#) |
| Power points (single and double) |
40,989 (#) |
| Fibre cement sheets |
84,487m2 |
| Iplex pipe |
409,415m |
| Toilet suites |
5,046 (#) |
| Wall and floor tiles |
92,516m2 |
| Sheet flooring (22mm thick) |
230,416m2 |
| Plywood sheets (19mm thick) |
5,164 (#) |
Recognising that one of our business' objectives is to grow its share of the housing market, our approach is to work with suppliers and contractors to minimise the impact of materials through substitution and by changing their composition and manufacture rather than focussing purely on the volume used. Though minimising waste, of course, is also a priority.
It is also important to note that embodied energy in the form of thermal mass can help to reduce the annual heating and cooling loads of a home and so there are a number of factors to be considered when examining how to reduce materials use in our homes. We analysed the quantities of energy embodied in housing construction materials, however, decided to withhold the analysis pending more work to resolve issues associated with accountability and additionality. Energy used for heating and cooling the home is generally equivalent to two to five times a house's embodied energy and the contents of a home generally account for more embodied emissions than the actual house itself.
Clarifying the Sources of our Timber
From our enquiries we are confident that at least 80% of timber sourced from current suppliers is certified. It should be noted that due to very limited penetration of Forest Stewardship Council (FSC) certification in Australia we are unable to select exclusively from FSC. The imported composite board we use is largely sourced from FSC certified sources. We are looking to document our sources of timber and to ensure that 100% of timber used in Clarendon Homes is certified by December 2007.
Commitments for Financial Year 2008
- Review materials use in Clarendon Homes and investigate opportunities to reduce the overall environmental impact of our houses.
- Develop Housing Design Guidelines which include minimum sustainability specifications and standards for all housing.
- Review procurement tenders and further upgrade sustainability considerations.
- Research industrial ecology and options for implementation on Investa Industrial Developments.
- Report volume and balance of site cut and fill on land subdivision.
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