Material Use
Specifying efficient use of materials and considering their impact from manufacture to disposal.
Embodied energy case study
The embodied energy of the major components for a 1½ storey house of 195 m2 is set out in the following table.
COMPONENT OPTIONS | APPROX WEIGHT (KG) | EMBODIED ENERGY | TOTAL EMBODIED ENERGY MJ/KG |
Floors - concrete | |||
17.5 Mpa concrete in floor slab for brick veneer cladding | 57,120 | 1.0 | 57,120 |
17.5 Mpa concrete in floor slab with lightweight cladding | 53,184 | 1.0 | 53,184 |
Concrete masonry foundation | 1,312 | 0.94 | 1,233 |
Reinforcing steel for slab on ground and foundation | 789 | 8.9 | 7,022 |
Floor – suspended timber (excluding garage slab) | |||
Concrete masonry foundation wall | 460 | 0.94 | 432 |
Foundation wall reinforcing | 147.5 | 8.9 | 1,313 |
Concrete to footings | 13,440 | 1.0 | 13,440 |
Timber framing* – air dried, gauged, 600 kg/m3 | 2,562 | 1.16 | 2,972 |
Particleboard flooring | 1,244 | 8.0 | 9,952 |
Windows and glazing | |||
Aluminium window joinery – factory coated | 144 | 34.3 | 4,939 |
Aluminium window joinery – anodised | 144 | 42.9 | 6,178 |
Float glass | 450 | 15.9 | 7,155 |
Timber framing* – 500 kg/m3 @ 12% mc | |||
Timber wall framing ground and first floor – kiln dried, gauged | 2,255 | 2.5 | 5,638 |
Timber roof framing – kiln dried, gauged, light roof | 1,875 | 2.5 | 4,688 |
Timber roof framing – kiln dried, gauged, heavy roof | 1,925 | 2.5 | 4,813 |
Timber ceiling framing and battens – kiln dried, gauged | 2,035 | 2.5 | 5,088 |
First floor | |||
Particleboard flooring | 544 | 8.0 | 4,352 |
First floor framing* – kiln dried | 1,505 | 2.5 | 3,763 |
Wall cladding | |||
Timber weatherboard cladding* – kiln-dried, dressed | 2,646 | 9.5 | 25,137 |
Brick veneer | 13,780 | 6.7 | 92,326 |
Fibre-cement sheet | 2,940 | 9.4 | 27,636 |
Roof cladding | |||
Steel roofing | 1,048 | 34.8 | 36,470 |
Concrete tile roofing | 10,350 | 0.81 | 8,384 |
Insulation | |||
Glasswool insulation | 294 | 30.3 | 8,908 |
Internal linings | |||
Plasterboard linings | 4,518 | 6.1 | 27,560 |
* Timber treatment not allowed for in embodied energy figure.
The table shows that the weight of materials used in construction can have an impact on relative embodied energy. For example, per kilogram of material, steel roofing has an embodied energy around 43 times greater than concrete roof tiles, but because the weight of steel required for a roof is far less than the weight of concrete tiles, the comparative embodied energy of a roof-lot of steel reduces to about 4 times greater than concrete roof tiles.