By Michael Rothenborg, November 2017.
Productivity in the construction industry is lower than in the global economy as a whole – and the gap has widened since the financial crisis, according to The Economist and the McKinsey Global Institute.
However, it is possible to build more efficiently – and more sustainably. In London, for example, Ramboll uses components manufactured in a controlled, offsite environment to increase efficiency. The method has a number of advantages.
It significantly decreases construction times by enabling construction and engineering challenges to be addressed before construction starts. On some projects, this has shortened a 12-month construction programme by 2.5 months.
Offsite manufacturing also reduces the number of workers at a construction site, because fewer activities are done onsite – which also reduces noise and minimises the impact of construction on the local area.
Another sustainability approach is to use materials like cross-laminated timber (CLT). At Dalston Works in Hackney, London, Ramboll has helped design the world’s tallest and largest CLT building by volume. The lighter construction weight of CLT enables smaller foundations, a critical factor at the Dalston Works site, which has High Speed 1 and Crossrail tracks passing beneath it.
Building with CLT has saved 2,400 tonnes of carbon – approximately 50% – compared to an equivalent residential block with a concrete frame.
Stabilising soft soil
Yet another approach is to reuse building materials. Ramboll has done this with success in several projects – at Katrinedalskolen (pictured), for example, a school on the outskirts of Copenhagen, where the reuse of bricks has lowered costs and reduced CO2 emissions by 70 tonnes.
Materials that cannot be reused in buildings might be used to prepare soil for their construction. A new technology (called UUMA2), developed by Ramboll in collaboration with Aalto University in Finland, is benefiting both the environment and the economy in Vietnam’s capital, Hanoi, among other places.
Soft ground has made some of the city’s central areas uninhabitable, but using cement or ash instead of, say, natural rock resources as a binder can stabilise the soil and make it fit for development.
The full extent to which these approaches can improve efficiency and reduce consumption is impossible to quantify, but, according to the McKinsey report “A blueprint for addressing the global affordable housing challenge”, reducing construction costs and unlocking land supply are the most efficient ways of narrowing the housing affordability gap.