02 March 2020
The Home-Grown Homes Project
The Home-Grown Homes Project is funded through the Rural Development Programme developed around the potential of Wales to become a high-value forest nation while creating high quality, affordable new housing. The unique initiative is a longitudinal study into supply chain development in the production of timber homes in Wales and looks into what is needed to increase the number and quality of these homes. Its focus is in the building of better homes – better designed, specified, manufactured and built.
The way we build today has evolved from the effects of market forces but it is not a process that helps us deliver better buildings. Thus, the Home-Grown Homes Project seeks to address this inefficient process by working with the clients who commission new homes, the manufacturers and contractors who produce them, and the growers and processors who produce the raw material we build with.
The project comprises a number of discrete investigations which focus on the sourcing of home-grown construction timber, the performance of timber homes from design through to occupation, working with a number of active construction projects using timber, the creation of an open source design resolved for timber construction, and an education project.
TRADA's Senior Timber Frame Consultant Robin Lancashire recently worked with David Hedges of Woodknowledge Wales to interview a number of housing associations and contractors. Robin has been involved with the Home-Grown Homes Project since its launch. Specifically, he examined the processes through which clients, contractors and their sub-contractors specify and use timber frame, barriers to its use, and the benefits it can bring through increased factory fabrication and standardisation.
Meeting the need for new housing continues to present a huge challenge to government, funders and the construction sector. A range of legislation, initiatives, guidance and financial incentives have sought to stimulate supply and have variously focused on the planning process, land supply and the development of skills and solutions. Despite this, the now decades-old housing crisis continues and the gap between the number of new homes the country needs and the number the country can build shows no sign of closing.
Design and build contracts dominate new build projects for housing associations. While many of them understand the benefits that timber frame can offer, their specification and tendering process is often based on procuring buildings for the lowest cost and lowest risk. This places material choices and design responsibility in the hands of the contractors.
For contractors, the cost balance between timber frame and its competitors would appear to be fine, with factors such as material prices, availability of bricklayers, experience of site managers, time and site conditions all playing a part in the decision making process. The decision on whether to build timber frame sometimes appears to be a very last minute one, based on the position of these changing factors at the time.
Timber frame has an established record of factory production and is evolving with higher levels of fabrication. Initiatives which see more modern forms of modular and platform-based construction, which take place in a factory environment off-site, are viewed as more efficient, more predictable, safer and more sustainable. It is well-placed to evolve and play a strong role in the area moving forward. There is a strong desire at high level in some large construction companies to make changes to the way houses are built to increase levels of factory fabrication – but with higher levels of fabrication comes a need for more investment, planning, standardising, drawing details, work processes, training, and quality checks. There are many expensive and time-consuming obstacles in the pathway for higher levels of house fabrication to succeed.
The design and construction of houses evolves over time to meet regulation change and take advantage of new products as they come to market. For example, as we move closer to a zero carbon way of living, it is likely that external walls will become thicker to accommodate more insulation. Other dimensional changes to materials used may be required as a response to regulatory changes, e.g. in structure, acoustic or fire regulations. The process of standardising timber frame construction should therefore be able to predict and accommodate likely changes in the near future and be adaptable with minimal costs to meet unforeseen changes. This may make the product perform better, but also cost more than a specification which currently meets the minimum criteria.
To take advantage of some of the benefits which standardisation can bring, a pool of good house designs and details which are repeatable and available for use by housing associations should be considered. The designs could incorporate cost effective structural timber frame design, practical layout, adequate room sizing and buildability (considering such things as material sizes, services installation, order of work, design for repair and replacement).
The potential for increased performance and reduced costs that timber frame and higher levels of factory fabrication can offer has already been realised by some. Others involved with the specification and construction of it are not yet working in a way to reap these benefits. Further cost and performance benefits can be realised by working together and developing standardisation wherever this can be effective. These areas are to be investigated in the next phase of our involvement with the Home-Grown Homes Project.
Robin Lancashire is TRADA's Senior Timber Frame Consultant and co-author of Timber frame construction: Designing for high performance 5th edition.
He has extensive on-site experience of timber frame buildings, in various forms at all stages of construction. His work involves him providing advice on best practice construction to all areas of the timber frame industry from architects and their clients, to main contractors and building owners.
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