Despite the latest UK building regulations stating a preference for Eurocode ‘limit state’ roof truss designs, the older ‘working stress’ design standards have remained the norm. But with Eurocode 5 becoming mandatory for roof truss design in Ireland earlier this year and with the UK set to follow suit, MiTek made the decision to only use the latest Eurocodes in the development of its next generation PAMIR roof truss design software.
As a result of this strategic move, and the rapid take-up of the software since its release in 2014, there’s now evidence that the system itself is helping establish Eurocode 5 as the standard in the roof truss sector.
Officially released in UK and Irish markets in May, PAMIR is the result of a ten-year development cycle and multi-million pound investment. It was written by MiTek’s European software development team and is designed for use by truss manufacturers across the Continent.
As more truss manufacturers move over to the new design software, and of course working in Eurocode 5, the question coming back to MiTek from the marketplace is ‘will we notice any difference in our roof designs?’.
The response from technical services director, Tony Fillingham is in the affirmative – and he says the differences will be positive.
"The first thing to note is that EC5 is a much more thorough design method than the national standards that it replaces," he said.
"When it comes to standard duo-pitch, mono and raised tie trusses, PAMIR delivers designs which have similar material content to the old BS5268-3 designs, with some savings in particular with the removal of span table trusses. Where the difference is likely to be more noticeable in design is in room-in-the-roof attic trusses. Here PAMIR and Eurocode design will often produce a reduced top chord timber size, whilst the more onerous floor vibration checks in the new code are likely to result in the same or slightly larger and stiffer bottom chord timber section being used."
What also gives the designer a ‘distinct advantage’, he added, is better utilisation of timber, with span limits extended to 12.075m for 35mm thick and 16.215m for 47mm thick timber.
Critically, long-standing MiTek software users all engaged early in the development process and have subsequently led the sector’s changeover to the new design code.
The new system has also brought new users into the MiTek fold, including names such as Arnold Laver and Harmony Timber Solutions.
In addition to the Eurocode design code, the software features an integrated roof layout, truss engineering and CAD environment, enabling quick production of complex roof quotations and production details.
As many roof designs undergo numerous minor alterations throughout the life of a project, rapid roof editing was also a key focus for the development team.
"Historically such minor changes, though small dimensionally, have often resulted in considerable reworking for the truss designer," said Mr Fillingham. "With this in mind the team set about ensuring that the software caters for last minute dimensional adjustments with a minimum of fuss. These features, coupled with reader software, which is freely available to other supply chain members, allowing them to view the roof model and check dimensional information for themselves, are, we believe, at the heart of why the truss industry has responded so positively to PAMIR’s release."
Last September, MiTek’s achievement in developing the new system was acknowledged when it was announced the winner of TTJ’s Award for Market Development in Timber Innovation. MiTek believes the initial success and market impact of the new software is set to grow.
