Much has changed in the past ten years as regards the use of timber in the design of new housing in the UK, so much so that the sheer number of good examples that can be seen around the country may come as a surprise to many. During this period, wider acceptance amongst architects, engineers and other construction professionals of a new generation of engineered timber products and systems, as well as of the advances made in wood modification technology applications, has prefaced the emergence of a whole new approach to building design in which timber in its many modern forms is very much to the fore. This has certainly been the case for commercial, educational and healthcare projects as well as housing, where timber products have increasingly been specified in preference to other, more traditional building materials and methods. The reasons for this are multiple: government pressure on industry to implement Modern Methods of Construction (MMC), for example, in which off-site manufacture, CNC-machined fabrication, minimisation of deliveries, fast erection times as well as on-site health and safety considerations are paralleled by environmental demands relating to carbon sequestration and energy use (both consumed and embodied).
The substantial visible changes that have emerged have not been in the landscape of volume housebuilding, however. Yes, the use of timber frame systems and SIPs has continued to increase in this part of the industry, especially in England and Wales where the application of these technologies has begun to catch up on Scotland where they form upwards of 70% of new house construction. We are now at a point where the actual numbers of new timber frame house completions in England and Wales exceed those in the more mature market north of the border and are making significant percentage inroads into the market there. There remains, however, a predilection to form the outer skin of much of this new housing in traditional garb: brick, render or stone - or a combination of all three - with perhaps an element, such as a porch, made from wood.
This latter approach - which some developers see purely as fashion appendages that they happily, if not a little cynically, refer to as ’gob-ons’ - disguises the real advances being made in the use of timber in the design and construction of housing in the UK. All around the country, different innovative approaches are being taken to address the chronic shortage of new and affordable dwellings. Some of these have been inspired by government’ initiatives to support more people into self-building homes for themselves, whilst recently enacted legislation is aimed at encouraging smaller, local groups of construction professionals to get together to ‘Custom Build’ a minimum of five houses and as many as 200. In order that land can be made available for this to happen, Local Authorities in England are obliged to maintain two registers: one of people indicating an interest in self-building, the other of land within their boundaries that can be made available for this purpose. Some Local Authorities, such as Plymouth, have become active supporters and/or participants in Self- and Custom Build projects, seeing this as a way to match their redundant land holdings to the availability of government finance for affordable housebuilding.
It is too early yet to see the results of these recent initiatives, but one thing is clear: timber products and prefabricated systems not only allow such projects to be constructed more quickly, they are also more accurate in assembly, ensuring the high levels of airtightness and thermal efficiency necessary to reduce the country’s over-dependency on fossil fuel and nuclear energy sources. Alongside the widening awareness of timber’s many construction benefits is a greater appreciation of the environmental advantages of using UK grown timber: principally a reduction in volumes of imported timber and a consequent decrease in the embodied energy (transportation etc.) associated with this.
Not all of the timber products and systems currently used in UK construction can be easily replaced, however: almost every solid laminated timber system presently employed - such as cross laminated timber, glulam, and LVL - is imported, with only a few UK manufacturers making use of the home-grown resources to create near-equivalent products: Inwood Developments Ltd in East Sussex (http://www.in-wood.co.uk) specialises in the use of sweet chestnut, Douglas fir and oak to manufacture bespoke glulam beams; whilst Buckland Timber (http://www.bucklandtimber.co.uk) in Devon is involved with BMTRADA in a testing programme to manufacture glulam from larch, Douglas Fir and Sitka spruce. The same is true of the increasingly popular modified wood products, where the only commercially-available, domestically-produced version is the thermally-modified Brimstone® wood (http://www.brimstonewood.co.uk) made from ash, sycamore or poplar being available (from Vastern Timber in Wiltshire). L&G Homes (https://www.legalandgeneral.com/modular) have invested in a 500,000 sq/ft manufacturing facility near Leeds with the aim of producing 3000 modular housing units per year from cross laminated timber it will manufacture on the same premises, but whether this will prove to be the sea-change needed to dramatically increase the use of UK-grown timber remains to be seen, as there are technical challenges involved for our sawmills in kiln-drying Sitka spruce and other appropriate species down to the 10-12% moisture content levels required.
To understand the changing timber needs of the UK construction industry, the forestry and timber processing sectors need to acquaint themselves with ‘Modernise or Die’, the Farmer Review of the UK Construction Labour Model that was published in October 2016 and which received a formal government response in July 2017. Even without the uncertainties created by Brexit, the review paints a bleak picture of the construction industry’s shrinking workforce and its failure to invest in skills, or to fully embrace the acceleration of the wider digital revolution: hence its ominous title. The success or otherwise of the modernised construction world that Farmer recommends will stand or fall by the effectiveness of its supply chains and it is here that the timber sector has to look to the future and recognise the need for medium-to-long term planning and serious investment in the technology required to meet demand.
The demand is already there, as is comprehensively evidenced in The Modern Timber House in the UK, the 240 page publication commissioned by Wood for Good to highlight not only the range of conventional and advanced timber technologies currently being applied in the building of new housing throughout the country, but also the wide range of applications they are being put to. Throughout its 14 chapters, this copiously illustrated book demonstrates the many innovative and inspirational ways that architects and engineers are finding to use timber in all its forms. Whether in rural, suburban or urban situations, from stick-built frames to multi-storey residential buildings formed from cross laminated timber, and from green timber to hybrid structures that integrate several different timber technologies, this is a book to encourage and inspire residents, clients, planners and other local and national government building control officials to demand more and better use of wood.
The author of ‘The Modern Timber House in the UK’, Peter Wilson is an architect and director of Edinburgh-based Timber Design Initiatives Ltd. The company’s work is founded on innovation in three inter-connected areas; professional education for architects and engineers in all aspects of timber design and construction; the development and use of new, timber-based products and construction systems; and the inception of built projects that demonstrate the new, high-technology frontiers being opened by engineered timber and modified wood products.