TImber building systems (offsite construction)

John Smith, technical director at Stewart Milne Timber Systems, discusses the benefits of offsite timber building systems in the face of potential weather-enforced downtime on-site

While many of us are growing weary of being confined to our homes during the pandemic, it has come with a greater appreciation of the warmth, shelter and sanctity they can provide, particularly during the colder months.

The industry has not been immune to the effects of the Covid-19 pandemic. A recent report from Homes England revealed that, thanks to disruption caused by subsequent restrictions, the delivery of housing programmes decreased in the first half of 2020-21, compared with the same period last year.

Similarly, a report by the House Builders Federation showed that property completions were down by an average of 35% in 2020 and supply statistics published by the Ministry of Housing, Communities & Local Government last year were among the lowest quarterly figures that had been produced in the series.

With the economic impact of the Covid-19 pandemic expected to have a knock-on effect on demand for affordable housing – according to the Local Government Association, the number of people on waiting lists could exceed 2m this year – housing secretary Robert Jenrick stated that the government intends to stick to its current target of 300,000 homes to be built across every part of the country, in order to help the next generation to get on to the housing ladder and the most vulnerable in society to find housing.


One million homes built over five years was always an ambitious, but not insurmountable, target; however, in addition to the complexities of Covid-19, winter brings further challenges.

Constructing well-performing homes, regardless of the weather

With an acute housing shortage, industry cannot afford weather-related delays throughout the winter months.

Among the many financial implications presented by weather delays, including cost overruns for labour, equipment hire and materials, and the subsequent disruption of cashflow, this allows very little leeway in meeting building demands during winter, when the weather can debilitate sites.

There is a solution to constructing well-performing homes, regardless of the weather, that stills adhere to strict social distancing rules: offsite construction.

When the weather creates difficult building conditions, the manufacturing of timber building systems can carry on uninterrupted – completed offsite through factory facilities, which allow for safety measures like physical distancing to be put in place – another added benefit from investing in this material.

Offsite panelised construction is less labour intensive on-site, requiring fewer personnel on the ground, unlike traditional building methods. With an acute skills shortage in the UK, it presents a way for construction to continue unimpeded, to high standards.

Requiring less heavy machinery and less energy, it provides a more sustainable, environmentally friendly method of housebuilding, and with a reduction in labour and costs associated with machinery hire, housebuilders who opt for offsite construction benefit from both cost-effectiveness and delivery capacity – essential in helping the industry meet government targets to address the housing shortage.

Initiatives such as the AIMCH housing innovation project – an industry-wide collaboration that aims to transform how homes are built – are progressing the development of industrialised offsite solutions.

Through our work on the AIMCH project, trials have seen plots erected without the need for scaffolding and pre-tiled roofs assembled on site at ground level, reducing the need to work from height, as well as having less labour on site, which is important in these times of social distancing.

Reaping the benefits of offsite construction

Financially, the accelerated build time of offsite construction delivers results, providing a quicker return on capital outlay and lower site preliminaries expenditure. Evidently, there are health and safety advantages to working offsite and indoors, where the risk of working at height in adverse weather conditions can be problematic. Factory conditions are stable no matter the weather, reducing potential hazards that can be faced by staff on-site.

Across the UK, we have the capacity to produce around 10,000 offsite timber building systems per year. That ability to manufacture offsite means we can build a typical detached plot between six and eight weeks quicker than traditional brick and block construction. A further example of construction time benefit would be a typical four-bedroom detached home, which could be manufactured, transported, erected, wind-protected and made watertight in as little as five days.

Although the UK’s construction industry is amid a robust recovery from the effects of the pandemic, with housing the biggest driver of construction growth, this momentum must be carried forward.

As the housebuilding industry perseveres throughout tiered restrictions and lockdowns, and companies re-examine their business strategies and models, it will become even more important to reduce building delays caused by adverse weather conditions. Offsite building does just that.



John Smith

Technical director

Stewart Milne Timber Systems

+44 (0)845 835 1527




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