Wood and modern methods of construction

[edit] Introduction

Modern methods of construction? Off-site construction? Modular housing? It’s pre-fab but not as we know it. Gone are the images of post-World War Two homes, quickly constructed to house returning soldiers and their families whose homes had been bombed during the war.

Today, off-site construction has higher aspirations. Though the turnaround for this style of build is still quick, there is no compromise on quality, strength, thermal insulation, or longevity.

[edit] Innovation

Britain’s housing crisis has been high on the agenda for years, but the volume of housebuilding still does not keep up with demand. The recession, skilled labour shortages and rising material costs are constraining the growth of the housebuilding sector. Hence Mark Farmer’s ‘Modernise or die’ report, which suggests the sector is afraid of change and stuck in the industrial age.

Innovation in housebuilding is key and off-site construction is the solution. Homes constructed off-site can be turned around in a matter of weeks. They are designed using the latest technology, ensuring minimal waste and allowing better quality control. Factories for modular homes can support the local economy by providing jobs for local people too.

During installation, disruption to surrounding residents and businesses is minimised with time on-site reduced by more than 70%. Less time on-site also lowers the risk of accidents for installers. Buildings constructed offsite are also lightweight, so the tonnage transported on the road is also reduced.

[edit] Timber technology

The housing industry is catching on, and both Legal & General and Swan Housing Association have invested in factories solely for off-site construction using cross-laminated timber (CLT). CLT can be used for a variety of housing types, ranging from terraced homes and detached homes to apartment blocks. The timber engineering used to create CLT ensures greater energy efficiency, strength, durability and outstanding acoustic qualities.

Meanwhile, Winchester City Council chose timber frame for the first houses it has built in 25 years. The council needed to provide affordable and adaptable homes to meet the needs of the local people. The use of timber frame was ideal for the constrained site as fewer raw materials needed to be delivered and stored on-site compared to traditional methods of construction.

With fewer load-bearing walls, the homes can easily be adapted in the future to suit the needs of the tenants. This along with high levels of air tightness shows that timber frame can be an ideal solution for quality affordable housing.

[edit] Affordability

Off-site construction is a cost-effective model, ideal for housing associations under pressure to deliver high-quality, energy efficient homes. In response to this pressure, Swan Housing Association established its NU build brand to build many of its new homes off-site, enabling it to cut its usual construction timescale by half.

Off-site construction reduces manufacturing process costs while providing local people with energy efficient and sustainable homes. It’s estimated that four million people in the UK are living in fuel poverty so making the housing stock more energy efficient is essential.

[edit] Investment

While off-site construction is already a proven success in Europe, the UK lending community is only now coming around to the idea of modern methods of construction. The Buildoffsite Property Assurance Scheme (BOPAS) gives lenders assurance that offsite constructed homes have a minimum lifespan of 60 years.

UK lenders need to get on board before foreign investors and developers jump in. The fast turnaround on construction means a quicker return on investment and with build costs lower than traditional methods of construction, profit margins can also be higher.

[edit] Why wood?

Wood is a carbon store, it has proven health benefits, it is a sustainable building material and its aesthetic qualities are hard to match. Building with CLT and timber frame incorporates all of these qualities while being lightweight and durable. It combines modern engineering techniques with one of the oldest building materials.

Sources: NU build; BOPAS; Offsite magazine; Elite Systems; Mortgage Introducer; Estates Gazette; TTJ; Legal and General

--Wood for Good

[edit] Related articles on Designing Buildings Wiki

• 11 things you didn't know about wood.
• Cross-laminated timber.
• Modern methods of construction.
• Off-site construction.
• Physical Properties of Wood.
• Testing timber.
• The differences between hardwood and softwood.
• Timber.
• Timber construction for London.
• Timber framed buildings and fire.
• Types of timber.