Leading UK offsite frame manufacturer, Donaldson Timber Systems (DTS), has become the first timber frame manufacturer to offer a verified Pre-Manufactured Value (PMV) score of 55% or more.
Following a six-month material and labour cost analysis completed by specialist construction consultancy, Cast Consultancy, the DTS Sigma II build system has been verified to achieve a minimum of 55% PMV, increasing to 58% for a detached home.
In conjunction with the Stewart Milne Group, the DTS timber system was tested on a live project, on a range of building typologies, including a 2-bed mid terrace, a 3-bed end-terrace and a 4-bed detached home. In these tests, the DTS Sigma II build system achieved a verified PMV of 55.7%, 55.8% and 58.4% respectively.
PMV is a way of calculating the proportion of a building’s construction that takes place offsite or near-site using any of the seven categories of Modern Methods of Construction (MMC). It can be achieved through a combination of off-site, near site and on-site manufacturing techniques, as well as through materials innovation and site-based process improvement and technology.
The PMV value of Sigma II is achieved by a combination of offsite elements of the build, including: traditional strip footings and in-situ suspended floor slabs; conventional brickwork external cladding; external doors installed on site; conventional felt, batten and tiled roof installed on site; services and internal linings to walls and ceilings installed on site; sanitaryware and kitchens installed on site; and pre-fabricated doorsets and stair flight, with handrail components installed on site.
The Affordable Homes Programme from Homes England, launched in 2021, requires all projects it funds to have at least 25% of the units delivered through MMC and a calculated PMV of 55%.
The verification by Cast confirms that DTS can achieve this target PMV value through the build system alone, when using the award-winning, BOPAS and BBA-approved, closed panel Sigma II Build System. While the system can be used in conjunction with other offsite technologies to further improve PMV, Sigma II achieves the target levels of PMV without reliance on any other off-site technologies.
There are numerous benefits of increasing PMV, including increased quality and performance, improved productivity, minimal waste, faster on-site delivery and reduced health and safety risk.
