In the latest issue of House Association Building and Maintenance magazine, Chris Duckworth, commercial director of SipBuild UK, explores how the housing shortage crisis is contributing to the considerable growth in the use of offsite construction methods as both public and private sectors are challenged to turn around the fortunes of the UK’s residential market.
In September 2014 the Confederation of British Industry (CBI) announced its predictions for the UK housing market. The forecast was fairly bleak. It suggested that in order to cope with the current housing shortage – which it labelled as ‘chronic’ – the public and private sectors would need to invest in the delivery of 240,000 new homes each year. A staggering challenge considering the CBI believe that more than 200,000 homes have been delivered in only four out of the last 14 years and in 2010 fewer houses were built in any year since WWII. It criticised current and past governments for not taking the issue seriously enough and threw down the gauntlet for them to turn around the fortunes of UK housing.
After the political wrangling has finished, the finger of responsibility to rise to this challenge will be pointed firmly at private developers and housing associations. But exactly how can housing associations provide a solution to this ever growing issue when funding has been cut to the bone and delivery is critical? Thankfully, modern methods of construction are increasingly becoming the answer, particularly when cost and time constraints are hurdles to overcome.
Until recently it’s fair to say that modern methods, such as Structural Insulated Panels (SIPS) have been perceived by developers and specifiers as an expensive route compared with bricks and mortar. The tide has now changed following a period of heavy product investment and innovation. Now, this construction method is gradually becoming the preference for not only social housing, but also private residential supply.
So what is the argument for housing associations using modern methods such as SIPs? Particularly with such ambitious targets to achieve to ensure a reduction is made to the current housing shortage, speed of development is key. Fortunately this is a major advantage delivered by offsite construction and the method offers benefits traditional approaches cannot compete with.
For an example, an average traditional two story brick and mortar house will take approximately three months to be completed and around three to six months to apply the finishes and utilities. In contrast if SIPs were used for the development of a property to the same scale a finished structure could be delivered in as little as two weeks.
Structural insulated panels are made with such precision that very little work is required on site other than installation. This means that by the time the panels are delivered to site the property is ready to be erected, which can be completed quickly and with a comparatively small crew.
What’s more, SIPs are far lighter than a standard masonry equivalent which means different foundations can be put into place providing a faster build and less expensive concrete deliveries to site.
These benefits alone make offsite methods incredibly attractive to housing associations looking to create volume and decrease turnaround time. They can also help completely transform an overstretched housing market.
In addition to time efficiencies, SIPs also have impressive energy and environmental credentials which housing associations and their residents can reap the rewards from.
According to the Carbon Trust 75 per cent of a building’s heat is lost through its fabric leading to significant environmental and monetary losses. As housing associations strive to find ways to reduce their properties environmental footprint they are starting to look beyond bolt-on insulation or energy harvesting measures and instead exploring the make-up of the home for energy preservation.
The best way to describe how SIPs work on a very basic level is to think of a jigsaw. Each piece has been designed specifically to join to the next to form a strong structure. This also achieves an airtight property that is incredibly thermal efficient.
And it’s not just how SIPs are joined together that offers this energy-tight seal, it’s also the way in which they are manufactured. Within each panel is a dense mass of urethane insulation which is so tightly packed that it prevents air from passing through it. This method of insulation differs greatly from the standard quilt style insulation that usually fills wall cavities. Firstly, it’s integral to the structure of the building and isn’t a costly bolt-on. And secondly, it’s not prone to sagging or deterioration which can expose voids where energy can seep through like standard cavity insulation.
With a SIPs structure approximately 96 per cent of the walls are insulated and almost all (99 per cent) of the roof. Compare this with a traditional timber frame where as little as 88 per cent of the walls have continuous insulation and you can quickly realise the benefits – so much so that SIPs have been used for specialist projects in the Arctic Circle where heat retention is vital. They’re also made using sustainable sources of wood.
If we’re going to rise to the new homes challenge, SIPs and other methods of offsite construction are the only real route the Government and housing associations have.