Engineers from Aston University, Birmingham and the University of South Australia have produced a cost model that estimates the impact of weather by season on each building activity, including portions of the build, such as bathroom pods, up to the entire structure.

The researchers have calculated the potential cost savings for builders using modular production techniques, where much of the construction happens offsite in controlled conditions and have published the findings in the International Journal of Sustainable Building Technology and Urban Development.

UniSA STEM senior lecturer and co-author of the paper Dr Ki Pyung Kim says weather is often identified as one of the top causes of delays and subsequent cost increases in the building industry, affecting 45% of projects worldwide.

“There are many pressures on the construction industry right now, including lack of skilled labour, reductions in profit margins, lack of sustainable materials and low productivity. The financial implications of weather are rarely considered except in extreme cases as the client normally bears the cost,” Kim says.

“By removing many of the onsite activities and replacing them with modules built offsite, builders can minimise construction delays caused by weather, thereby keeping the costs from blowing out.”

The savings come in at approximately $40,000 on a build worth $6.4 million. This 0.6% saving may initially seem minor but takes on significant meaning in the current climate where average construction profit margins are just 4.2%.

While modular construction techniques have several benefits, including faster builds and a more controlled working environment that protects high-quality materials from the weather, there are some drawbacks, such as a limited supply chain and a lack of flexibility in both design and supply. The upfront costs of modular components are also expensive, but this needs to be weighed up against losses incurred by weather holdups.

“The global housing sector is dominated by traditional construction methods, but the industry is approaching a crisis point, particularly in relation to a skills shortage, that may force a change to modular and other offsite techniques,” Dr Kim says.

“The Federal Government has set a target of delivering one million affordable homes over five years from 2024. To ensure this target is met, Infrastructure Australia has mandated modular construction for 80% of social housing projects by 2030.”

Construction costs are typically between 43 and 46% of overall costs, which is why much of the existing research focuses on this area.

“When working in a factory environment there is a more protected and controlled atmosphere, and this will improve worker welfare, productivity and reduce health and safety costs, with fewer loss of workdays due to ill health and accident,” Kim says.