System specification is crucial to success when planning to build energy efficient, sustainable homes. One main decision self-builders face is the choice between traditional or modern methods of construction.
A recent article published by an alliance set up to represent the traditional construction industry claims that the timber frame market share in the UK is currently the lowest it has been in many years.
The online article also stated that traditional methods of construction offer better sustainability at a lower cost. Contrary to this, the Structural Timber Association (STA) released figures at the end of 2014 confirming a record number of orders for the timber frame sector last year, with some companies seeing a 100% increase in business and reporting continued growth.
The STA confirmed that the timber industry has reported increases in sales of up to 163% in recent months. These figures are a direct result of the widely reported shortage of materials in other sectors and the recognition that timber brings speed of build as well as superb energy efficiency. Timber frame is widely acknowledged as being both an economical and efficient method of construction. Because the frame is built off-site in controlled factory conditions, this type of construction offers greater freedom and opportunities for adaptability.
Factors that drive energy efficiency are bespoke specification issues such as levels of insulation and airtightness. The gap between predicted and actual energy performance is now well documented with the publication of the Zero Carbon Hub’s report, ‘Closing the Gap Between Design and As-Built Performance.’ Timber frame offers considerably more certainty when it comes to delivering as-designed performance, with U-Values that are significantly easier to predict.
The minimum U-Value required in the external walls of a new-build house is currently 0.30 W/m2K and timber frame solutions are often able to achieve less than 0.10 W/m2K. Blockwork home suppliers claim around 0.25 W/m2K, which confirms that timber frame structures vastly outperform more traditional methods of construction in terms of heat retention.
Timber frame houses are also sealed, preventing moist air from getting inside the building and keeping warm air within. It is clear that by using prefabricated timber frame solutions, self-builders can achieve a rapid dry building envelope – typically 30% quicker than traditional methods of construction.
Timber frame construction is less weather-dependant, which makes project planning more predictable and reduces the risk of setbacks. Many construction follow-on trades, such as electricians and plasterers cannot work in exposed weather conditions and therefore cannot start until the interior is protected from the elements. These trades can start much earlier in the construction programme of a timber frame house, which results in a faster completion time.
Timber frame providers are able to erect an average four-bedroom house, whilst making it watertight, in just seven days – a claim that is far beyond the capability of any traditional methods. Houses with all-masonry walls require a longer period for mortar and plaster on the inside to dry out, extending the build time by several weeks.
Self-builder Simon Cowey appointed a timber frame provider for two self-build homes: a bungalow for his parents and a four-bedroom luxury home for himself and his family. Simon comments on why a speedy build was essential for his project: “Time is money, an old but relevant adage. As both my parents and family were in rented accommodation during both builds, the interest on our bank loan funding was rising. This meant that securing the earliest possible move in date was essential. We were drawn towards the ease and efficiency of timber frame construction; it is a fast and effective way to build an energy efficient new home."
Timber frame is now the UK’s fastest growing method of construction and a core reason for this is the sustainability benefits it delivers. The latest building regulations demanding the use of more sustainable materials make this a major factor that self-builders cannot ignore. Timber delivers a high-performance building solution that directly contributes to achieving high Code for Sustainable Homes levels. The Fabric First Approach creates a high performance, thermally efficient building envelope that can meet higher levels of Code, without the need to rely on expensive energy saving bolt-on technologies, such as solar panels.
The Structural timber from well-established timber frame companies is sourced from managed forests, making it highly renewable and sustainable. Planting trees for the production of timber benefits the environment and its harvesting, production and transport are seen to produce less CO2 than traditional construction materials.
The claim is that the traditional construction industry is pulling together to counteract so-called misplaced perceptions on modern methods of construction. However, I would have to agree with Andrew Carpenter, Chief Executive of the Structural Timber Association, who that their members are now witnessing the fruits of their labours. As an association, the STA have worked hard to build an understanding of timber in terms of sustainability and performance, coupled with the relationships they have forged with other organisations.
As far as I’m concerned, the future is hugely positive for the timber industry and it is extremely exciting to be a part of this. With consumers recognising the advantages of offsite construction, this is an industry that will continue to thrive.