Timber frame homes now account for over a quarter of the new-build properties in the UK and that number is continuing to rise as developers look to turn projects around more quickly. By Michelle Gordon
Timber had somewhat fallen out of fashion as a building material but in recent years it has started to make a comeback driven by its excellent environmental credentials, versatility and speedy build times.
Figures released by the Structural Timber Association (STA) last year showed that the market share for new-build timber frame homes had increased to 27.6% – a figure that is expected to have risen to nearer 30% when the STA releases its latest data in October.
There are many benefits of building with timber frame and a typical home can be built in a matter of weeks, saving money onsite, and allowing homes to be sold or rented out sooner, giving a quicker return on investment. There are fewer vehicles to site, with quieter and less hazardous conditions, as well as less waste than with other construction methods.
Factory-built homes are also precision engineered, meaning that they meet consistently high standards and have excellent environmental credentials. Speed of build is a huge driver for growth said Christiane Lellig, campaign director for Wood for Good. The advancement of custom-build plots throughout England is also contributing to growth, she said, as is a lack of bricks and blocks.
“Change is happening faster than ever before with the Modernise or Die report leading the way,” said Lellig and there is a growing appetite for offsite construction among architects and engineers with an increasing number of leading developers using offsite methods.
But while use of timber is continuing to grow its market share remains relatively small compared to other building materials and “there is some frustration amongst architects and engineers that many clients still think brick and block first rather than being open to new approaches,” said Lellig.
“We need to understand concerns and co-develop solutions, where necessary and possible,” she said. “Where we are dealing with genuine misperceptions, we will need to provide evidence in the form of performance data and because numbers can’t overcome emotionally rooted ‘prejudice’, we will need to offer physical experience with the timber construction process and the completed timber buildings. In short, exposure to successful projects, in-depth discussions with peers using timber solutions etc.”
There is still some way to go before timber is considered as a mainstream building material but its use in high-profile projects can only boost its appeal and introduce a whole new audience to the benefits of building with wood.
A RIVER RUNS THROUGH IT
Development: Aldcliffe Yard
Aldcliffe Yard is an award-winning development of custom-build houses and refurbished homes located in a British Waterways conservation area in central Lancaster. The development on the site of a former British Waterways office and yard includes one detached, two semi-detached and five terraced properties, making it the first terraced custom-build scheme to be delivered in the UK. Alongside the three and four-bedroom new-build houses, there are six homes, which were created from heritage canal-side buildings.
The scheme located within a conservation area alongside the Lancaster Canal was masterminded by H2O Urban, a joint venture between private property developer Bloc and charity the Canal and River Trust and profits from the development will be reinvested to maintain waterways across Britain for future generations.
The local planning department gave clear specifications about the materials to be used and the footprint of the buildings, to ensure that the new properties remained sympathetic to the local surroundings and they were built with natural stone walls, timber cladding, slate roofs and timber sash windows.
H2O gained planning permission for the development’s external design and then purchasers bought plots outright and were able design their own layouts and hand the build project management back to H2O specialists.
The properties were built using timber frame, enabling fast and cost-effective construction and allowing buyers to move internal walls to create kitchen-diners or to add or remove ensuite bathrooms, during the design phase.
Development: Exemplar, NW Bicester Eco Town
Location: North West Bicester, Oxfordshire
A2Dominion’s development in North West Bicester is a 393-home project, aiming to deliver the most sustainable living in the UK for its residents and 94 homes were built as part of the first “Exemplar” phase. With the homes designed to achieve true zero carbon rating, delivering energy efficient, good-quality affordable housing was crucial to the project’s success and timber frame was an ideal fit for the priorities of the scheme.
PROJECT BRIEF – Stewart Milne Timber Systems was appointed to work with A2Dominion and Willmott Dixon, the main contractor, on the project which will be the only eco town still to adhere to the Government’s original Eco Town Policy Planning Statement.
Stewart Milne Timber Systems’ role in the project was to provide its Sigma II Build System, with novel C-stud technology, for 94 of the first 393 homes, as part of the “Exemplar” phase of the project. Initial infrastructure work began in April 2014, and construction work on the homes commenced in the summer of 2014. The first residents moved in to this phase of the project in 2015.
The development will feature the UK’s largest domestic solar panel array, with 17,500 square metres mounted across the rooftops of all homes to generate electricity. This will include freestanding photovoltaic (PV) panels, overlaid PV panels and inset PV tiles, with some garages benefiting from green roofs. It will also include a range of additional features, aiming to minimise its residents’ impact on the local environment.
These will include rainwater harvesting systems to recycle water; home information systems displaying energy, water consumption, and real-time information on local public transport; an electric car club and eco-pub; optional electric car charging points; and high-speed fibre-optic broadband to promote home working and reduce car journeys.
BUILD PROCESS AND KEY BENEFITS OF PROJECT – The timber frame system was precision engineered offsite, which limits defects and means there is less preliminary site preparation, which in turn reduces costs.
Other benefits included reduced health and safety risks and avoiding weather interruptions. The first phase was designed with a fabric first approach, complemented by renewable technologies, keeping the build fabric central to creating a sustainable community.
The homes will attain Code for Sustainable Homes (CSH) Level 5 through excellent heat retention and air tightness, with a 0.15 U-value, air tightness of 3 and thermal bridging of 0.04. Much of this is achieved through the build fabric, with pre-assembled flat roof modules and insulated floor cassette edges, meaning a pair of semidetached homes can be weather tight, air tight, secure and fully insulated within 72 hours.
Air testing is also conducted prior to first fixing, building in assured performance of the fabric. Stewart Milne Timber Systems’ ‘fabric first’ approach is a critical element of achieving high levels of environmental performance, with energy efficiency built into the fabric of the building.
Development: The Serpentine
Designed by Make Architects for Thames Valley Housing (TVH), The Serpentine is a modern interpretation of the traditional Victorian terrace with an ‘S’ shaped building, which comprises 94 houses and flats over three floors. Meeting the highest standards of energy efficiency was important to TVH, a registered social landlord, as was speed of delivery and a build cost of less than £60,000 per home.
Stewart Milne Timber Systems’ (SMTS) Sigma II Build System ticked all of the boxes and SMTS played a crucial role in the project, from the initial design through to the supply and erection of the closed panel timber build system.
The end result is a sustainable development of homes featuring energy efficient U-values of 0.15 W/m2K in the external walls, 0.15 W/ m2K in the ceilings (pre-insulated cassettes), and 1.4 W/m2K windows, pre-fitted to the external walls.
The experience and expertise of SMTS’ technical and design teams was integral to the viability of The Serpentine. It identified design and structural solutions, which enabled the company to meet the brief while keeping costs under control. For example, the whole building is segmental, with straight walls, and in each house type all internal walls are set at right angles to one of the party walls. That allowed SMTS to manufacture all of the floor and ceiling cassettes in its factory on its fully automated lines.