Embodied energy: traditional masonry vs modular
A report by FACIT homes calls for embodied energy to be considered in Code for Sustainable Homes
House design in the UK is changing, through regulation, costs, and the drive to push down energy usage. Traditionally UK houses are of masonry construction but more and more we are seeing houses constructed using modern methods of construction such as modular panel systems. However, questions still remain as to whether these construction methods are any more sustainable.
Measuring the embodied energy of a building is a difficult task and is often lacking from environmental claims and certification. The Code for Sustainable Homes pays little attention to embodied energy and instead focuses mainly on energy use. This is compounded by embodied energy often being considered insignificant when set against the lifespan of a highly inefficient building.
FACIT homes have commissioned a report from environmental engineers XCO2 which looks at the embodied energy of high performance housing. The report considers the low emissions levels of new housing stock and how these contribute to global warming.
FACIT compared their homes, created from a system of spuce plywood, cellulose fibre and timber cladding with a more traditional masonry construction of concrete block, polyurethane insulation and a brick skin.
The study analyses embodied CO2 data from cradle to factory gate with emissions relating from material transport to site and the construction process considered separately.
The construction methods chosen were specified based on a highly insulated building envelope with all main elements achieving a U-value of 0.14W/m2K or less, in line with Passivhaus standards.
The assessments used in the study were carried out through BIM, and not through the use of actual case study projects. A BIM model was created and the different construction methods were applied to this for analysis.
The research found the masonry construction to contain 48,000kg more embodied CO2 than the FACIT homes model, and 6250kg more than a standard SIP build.
The report went on to call for the embodied energy of buildings to be considered in Code for Sustainable Homes assessments. From this research FACIT homes are moving to develop a publicly available database of embodied energy values to help architects and specifiers make informed materials choices.
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