TY - JOUR
T1 - Optimal roofing solutions for Australian green buildings : a life-cycle cost perspective
AU - Illankoon, I. M. Chethana S.
AU - Tam, Vivian W. Y.
AU - Le, Khoa N.
AU - Wang, Xiangyu
AU - Wang, Jiayuan
PY - 2020
Y1 - 2020
N2 - Thermal insulation is a significant factor in building construction. As a result, Green Star in Australia requires building envelopes to be properly insulated. Further, green buildings require at least 15% above the required R-values (m2K/W) for achieving Green Star credit points. Thermal insulation of the roof depends on various factors such as insulation material, sarking material, air films and roof covering. Therefore, there are many options with different combinations available to obtain the required total R-values. This research aims to identify optimum solutions for roofing solutions considering the required R-Values and the life-cycle cost. There are ten commonly used roof types in Australia. For each of these roofs, there are many variants available with different material. Therefore, this research calculated the life-cycle cost for more than 2000 options in roofing solutions, and analyse the options to identify the optimum solutions for each climatic zone in Australia. Life-cycle cost adopts net present value (NPV) technique for the calculations. The outcome shows that initial cost and the replacement cost significantly influence the life-cycle cost. Further, maintenance, replacement and the disposal cost vary from 47% to 69% of the life-cycle cost. Sensitivity analysis concludes that the discounting rate has a significant influence on the life-cycle cost of the roofing solution. However, the changes in labour rate has a slight impact on the life-cycle cost of roofing solutions.
AB - Thermal insulation is a significant factor in building construction. As a result, Green Star in Australia requires building envelopes to be properly insulated. Further, green buildings require at least 15% above the required R-values (m2K/W) for achieving Green Star credit points. Thermal insulation of the roof depends on various factors such as insulation material, sarking material, air films and roof covering. Therefore, there are many options with different combinations available to obtain the required total R-values. This research aims to identify optimum solutions for roofing solutions considering the required R-Values and the life-cycle cost. There are ten commonly used roof types in Australia. For each of these roofs, there are many variants available with different material. Therefore, this research calculated the life-cycle cost for more than 2000 options in roofing solutions, and analyse the options to identify the optimum solutions for each climatic zone in Australia. Life-cycle cost adopts net present value (NPV) technique for the calculations. The outcome shows that initial cost and the replacement cost significantly influence the life-cycle cost. Further, maintenance, replacement and the disposal cost vary from 47% to 69% of the life-cycle cost. Sensitivity analysis concludes that the discounting rate has a significant influence on the life-cycle cost of the roofing solution. However, the changes in labour rate has a slight impact on the life-cycle cost of roofing solutions.
KW - building materials
KW - insulation (heat)
KW - roofing
KW - sustainable buildings
UR - http://hdl.handle.net/1959.7/uws:48244
U2 - 10.1680/jensu.17.00064
DO - 10.1680/jensu.17.00064
M3 - Article
VL - 173
SP - 30
EP - 41
JO - Proceedings of the Institution of Civil Engineers: Engineering Sustainability
JF - Proceedings of the Institution of Civil Engineers: Engineering Sustainability
IS - 1
ER -
