A timber frame building is a complex structure and even designs for relatively small-scale projects require the highest levels of accuracy and meticulous attention to detail – mistakes are extremely costly.

Which is why a Gloucestershire company is making use of Archicad’s 3D modelling capabilities to pre-empt problems on site and identify misalignments or missing elements during quotation and planning stages.

With such specific requirements, the Oak Frame Carpentry Company needed software flexible enough to accommodate a bespoke add-on that it knew would be necessary to enable details of its specialised operations to be incorporated into the 3D models created.

The company employs two full-time designers to undertake the planning and design of projects, in both traditional and contemporary styles – from small-scale conservatories and domestic extensions through to houses, bridges, barn conversions and public buildings. The latter category includes Chapelfield Retail Development in Norwich, an arcade structure 8m tall and over 60m long incorporating more than 60 tonnes of oak.

While the firm does not have the professional indemnity required to provide legally endorsed architectural plans, architects undertaking the design will often bow to the company’s in-depth knowledge of timber frame. As a result, a great deal of in-house time and effort has always been put into developing detailed design recommendations for the jointing of every timber frame.

The main preoccupation with such complex jointing is the avoidance of errors, which are costly in terms of time, money and materials. Director Tim Potts explained: “None of the wood we use is uniform so no line is absolutely straight, requiring precise calculation to ensure a perfect match when the sections (which we prefabricate off-site) arrive on-site.

“It’s really critical that, when it comes to fitting these components together in three dimensions, they match perfectly. “Before the move to 3D design, we had to rely on human skill and experience, but mistakes did happen, and once a piece of timber has been jointed it’s irreplaceable.”

With the design and specification being so involved and complex, the pricing for each project – done on an individual joint-by-joint basis for every job – is also time-consuming. And all this input is undertaken before the company can even guarantee it has won the job.

In an effort to minimise time input into quotations and maximise the accuracy of designs produced, Mr Potts researched the merits of CAD systems and decided this was the only way to achieve the company’s goals.

Multi-level functioning

Graphisoft’s Archicad software was selected for its multi-level functioning (adjustments made in one aspect of the design will be passed through to all files) and file sharing capabilities.

For his requirements, Mr Potts identified the need for a bespoke add-on to Archicad. This was developed by Bristol software design company Encina and has become known as Framewright. Features included allowances for calculations on curved timber, custom profiles of any section, and the ability to rotate in 3D space.

“The Framewright add-on took some 18 months to evolve, but has more than made back our outlay over the two-and-a-half years we have been using it,” said Mr Potts. “It is quite straightforward to operate, though more in-depth projects can make use of more complex features. It has meant adjusting the way we think about our designs, the way we quote and charge for them, and the way we present to clients.”

Spreadsheets, 2D plans, material requirements and scheduling documents are all produced direct from the details included within the Archicad model. This significantly reduces set-up time for each project, ultimately enabling the company to handle a greater number of projects and, with the added perceived value, allowing a significant premium to be charged.

Improvements

Indeed, the integration of the new software into the working practice has facilitated a broad range of improvements as particular projects have arisen.

For Britannia House – a 16th century listed building in Gloucestershire – restoration was a complex concern since special consent was required from the Council in order to progress. Using the 3D modelling to visualise plans to the Council (and to produce the cutting list and workshop drawings) ensured that approval was given quickly and the work was completed accurately.

“Being able to visualise plans has proved invaluable in many ways,” said Mr Potts. “Not just in terms of technical planning but also to ensure we really do achieve what the client wants.

“The software enables the entire project to be managed more accurately with no omissions – and with no costly re-work. Almost every aspect of the work flow in this company has been improved.”