Using offsite manufactured timber frame systems for your project
We’ve used offsite manufactured timber frame systems on a range of our projects - from large housing projects to one-off houses - and it’s a great way to build which has many advantages.
Offsite timber frame manufacturing is a type of Modern Method of Construction (or MMC), an increasingly popular type of construction involving components of the building envelope being designed as a whole system, constructed in a factory, before being brought to site for assembly. At the most extreme, this might mean whole volumetric sections of the building, complete with windows and cladding, coming to site and being stacked up to form the building.
For the low-rise housing projects and one-off houses this usually involves a timber frame system comprising timber frame panels forming walls and sometimes floors and roofs coming to site and being fitted together to form the building super-structure. The panels might be ‘closed’ which means they are pre-insulated in the factory - or they might be an ‘open’ system, where they are insulated on site. Breather membranes and airtight boards are often installed in the factory, and it’s possible that windows are pre-installed as well. At its most simplistic, pre-cut timber framing elements - studs, joists, sheathing boards - can be delivered to site, to be put together like flatpack furniture.
Allowing more of the construction process taking place in a factory has many advantages. Factory conditions means there is greater quality control over the build - everything is measured, cut and assembled, and the insulation installed with precision, resulting in a warmer, more airtight, longer lasting building. Using timber frame is a sustainable choice anyway, but there is less waste in the factory than there is on site, making it better for the planet. Once it arrives on site, construction times are much quicker than a traditional build - which is great for our clients. But it also means there is less mess, noise, and construction traffic on site, as much of the work takes place elsewhere. The controlled factory conditions also improve health and safety for construction workers.
As well as the construction benefits, using a timber frame system has advantages in that it has been carefully and rigorously designed and tested to conform to particular standards. This is particularly useful when aiming to achieve low energy or passivhaus homes - where getting the junctions between floors, walls, and roofs to work well and eliminate thermal bridging - and having the data to back this up - is really critical. Using a specialist timber frame system - such as PH15 [https://www.phhomes.co.uk], Beattie Build System [https://www.beattie.io] or MBC [https://mbctimberframe.co.uk] - which can be partially manufactured offsite and has been designed for passivhaus, is a great option for new eco-homes.
Despite the many advantages, some systems can be limited in what they can achieve - in terms of their thermal performance, and also how flexible they can be in achieving the detailing or appearance that our clients are looking for. This route also requires that the design is fully resolved in advance of construction - where traditional builds might have a bit more flexibility, once the timber frame has gone into production then the opportunity for design changes is limited. Access to site might also impact on the suitability of different timber frame systems. It’s therefore really important to choose the right system for your project, which is something that we can help you with as the design for your project develops.
Here are some of past and current projects involving offsite manufactured timber frame systems:
Hazelmead, Bridport Cohousing - Our award winning project for Bridport Cohousing used a closed panel system by SO Modular. [https://somodular.co.uk/]
Sailcloth House. This new eco house was built using a closed panel system by All Timber Frames. [https://alltimberframes.co.uk]
Homes for Bristol City Council at Stockwood. The contractor is currently preparing the site for the arrival of the first timber frames in July. Donaldson Timber Systems are supplying the Sigma II pre-insulated closed panels for the external walls, open panels for the internal walls, with timber i-joist floors and roof trusses. The windows and brick cladding will then be installed on site. [https://www.donaldsontimbersystems.com]
Bristol Ecohouse. We are currently exploring options for using a specialist passivhaus timber system on a new passivhaus in Bristol.
Sailcloth House