CANVASSING OPINION ON THE TOPIC OF ‘A COST-EFFECTIVE APPROACH TO OFFSITE CONSTRUCTION AND MITIGATING CLIMATE CHANGE’, AIQS GARNERED A NUMBER OF CRITICAL INSIGHTS FROM A SELECTION OF MEMBERS AND ACADEMICS, PRESENTED HERE.
“By adopting an educated approach throughout design and cost control processes, we can advise which materials and construction methodologies minimise climate change through resource and labour minimisation and modular construction. Materials with a lower environmental impact such as VOC free paint and formaldehyde free joinery can reduce, over the long term, the environmental impact construction materials have throughout a projects life cycle without materially impacting cost or quality.” Lucas Hinton and Graham Moore, GRC Quantity Surveyors.
“By adopting an educated approach throughout design and cost control processes, we can advise which materials and construction methodologies minimise climate change through resource and labour minimisation and modular construction. Materials with a lower environmental impact such as VOC free paint and formaldehyde free joinery can reduce, over the long term, the environmental impact construction materials have throughout a projects life cycle without materially impacting cost or quality.”Lucas Hinton, Director + Graham Moore, Senior Quantity Surveyor, GRC Quantity Surveyors.
Mitigating climate change means reducing our carbon emission and by doing so limiting the intensity or speed of climate change. However, climate change adaptation is equally important in building. How can we adapt / be more resilient to climate change as it occurs by using better building approaches? Making buildings that remain comfortable and safe in generally warmer or more extreme weather.”
“Three main options exist if we want to reduce carbon emissions from building overall. Firstly, build more efficiently to minimise construction-based emissions. Secondly, increase our use of low-carbon (and preferably renewable) materials and economically withdraw from carbon-intensive materials. So, decrease the amount of embodied carbon in the materials – using less steel and concrete and more wood. Renewable materials such as timber also sequesters atmospheric carbon into the building.
Thirdly, design buildings with a lower net energy requirement for the amenity they provide. This is a broad requirement as it includes improved thermal performance, efficient spatial arrangement, use of site-generated energy (passive solar gain, heat and electricity), access to public transport, and a range of other factors. Of these three options, the biggest climate change mitigation benefits are from the second and third points. The first is relevant, but its carbon impacts are much smaller than the other two. The biggest climate change adaption benefits are from the third point.
If we approach this from the other direction, the biggest overall benefits from offsite construction are speed of construction onsite, construction accuracy, and the potential for improved overall quality. The overall cost of building offsite compared to onsite seem to be similar, but speed to completion and reduced site impacts seem to make offsite building a winner in most cases. Speed of construction onsite reduces delays, inefficient material handling, site waste, and overall transport requirements. All these should lead to lower overall carbon emissions. Construction accuracy and the potential for improved overall quality probably provided the greatest direct carbon reduction benefits that can be attributed to the construction method. If the insulation, windows and connections are more accurately and effectively installed, the overall building should have improved thermal performance and durability. It should last longer and perform better, both of which are very important for climate change reduction and adaptation. Of course, this is all moderated by the quality and intention of the design overall. A building designed to chew up energy over a short life will do so whichever way it is built.”
“Offsite construction assists / does not hinder using low-carbon material, such as timber. For me, timber and wood products are the ideal basis for offsite construction as they are light, highly workable, very low carbon and can deliver similar performance to other material on their own or in combination.
In summary, offsite construction allows us to build higher quality buildings faster and with low-carbon materials. These should help reduce climate change impacts.” Professor Gregory Nolan, University of Tasmania
“Several recent reports have revealed the potentially devastating impact the construction industry has in terms of its contribution to climate change. Around the world, construction accounts for about 25% of Greenhouse Gas (GHG) emissions. In terms of infrastructure, large cities consume over 65% of the world’s energy, resulting in 70% of the world’s CO2 emissions.
Concrete is the most common humanly made product on earth. It is second only to water as the most-consumed resource on the planet. While cement – the key ingredient in concrete – has shaped much of our built environment, it also has a massive carbon footprint. Cement manufacturing alone accounts for 7% of global CO2 emissions. If the cement industry were a country, it would be the 3rd largest emitter in the world – behind China and the US. It contributes more CO2 than aviation fuel (2.5%) and is not far behind the global agriculture business (12%).
Reports by the BBC in recent times have focussed primarily on our dependence on concrete, and the environmental impact this dependence brings. In many countries, and often illegally, stripping billions of tonnes of sand and gravel from beaches and rivers, it has made coastal communities more vulnerable to damage caused by storms, or with water tables alongside rivers falling affecting farming. This is twice the yearly amount of sediment carried to the world’s rivers, meaning we are consuming sand faster than nature is replacing it. By 2060, the demand for sand and gravel for construction will double to 55 billion tonnes.
Even with changes in the technology used to produce cement and concrete along with innovation that allow a progressive decarbonisation of the processes to obtain new types of more efficiently made cement, the construction industry needs to consider the amount of raw materials, and a greater use of recycled and manufactured materials it uses to become more environmentally friendly.
Switching to more efficient production methods, both on site or offsite and improving how buildings are either refurbished or demolished at their end of their lifecycle are but some of the proposals in achieving better environmental outcomes.
Is offsite construction more environmentally friendly? Traditional onsite construction methods (in situ construction) are drawn-out processes in comparison to offsite techniques. Using offsite technology (construction) presents an ideal opportunity to reduce the construction industry’s carbon footprint.
Whilst no construction method is without waste, many of the resources used can be recycled. Factory-produced elements result in less waste, as design and subsequent technology eliminates or minimises abortive works prior to production, with offcuts from processes often be reused or recycled at the factory. Fewer trades means fewer vehicle trips to site. Timber products used in systems such as Cross Laminate Timber (CLT) act as a carbon sink, further reducing greenhouse gas emissions. Offsite construction methods could act as a viable step towards reducing CO2 emissions.
Is offsite construction more cost effective? In the absence of any updated regulations, a major barrier is the lack of client demand for buildings to be designed and constructed to address climate change. This sits alongside the perceived notion to include these mitigation and adaption measures comes at an additional cost of building.
Yet many, when asked, suggest better regulation to address climate change would be beneficial to the construction industry. This would create a ‘level playing field’ for the industry and encourage innovation in the sector.
Offsite construction involves different types of jobs requiring different skills. With a larger uptake by industry to move many key elements of a construction cycle from on-site to off-site, this can reduce and mitigate many of the issues, risks and thereby additional costs factored in most construction sites e.g. time delays, industrial relations, and safety. Safety in the building industry could be greatly improved by moving production to a controlled environment.
For those elements of construction which can be done offsite, many offsite contractors have perfected production methods to allow for a more efficient way to construct modular buildings and components; more cost effectively and to a reduced program deadline.
Working offsite in warehouses and other controlled environments also means external factors such as weather directly impacting manufacturing of the offsite component are substantially mitigated, thereby reducing time on site. Internal factors such as design, quality, greater automation and thus product outputs are better managed and controlled, with the supply-chain cost savings passed onto the Client.” Louise Vlatko and the Xmirus team
“Working offsite in warehouses and other controlled environments also means external factors such as weather directly impacting manufacturing of the offsite component are substantially mitigated, thereby reducing time on site. Internal factors such as design, quality, greater automation and thus product outputs are better managed and controlled, with the supply-chain cost savings passed onto the Client.”Louise Vlatko, Director, Xmirus (and team).
“Offsite construction is cost effective due to higher productivity based on the reduction in manpower and time. Offsite construction mitigates climate change because the manufacturing of the materials is done in a controlled environment therefore there is a reduction in construction waste, dust and noise pollution that would usually occur on construction sites.” Peter Fong, Rider Levett Bucknall, Singapore.■