Expert envelope design

When disparate elements are brought together onsite, it is down to the specifier to assess whether the selected combination of materials delivers the required levels of performance. Steve Thompson, Managing Director for EOS, discusses those challenges when specifying building envelopes.

For some time, there have been concerns regarding the potential gap between design and as-built performance of buildings and now there is also the new building regulations to consider fire resistance for buildings over 18m. As ever, the devil is in the detailing, and what was intended by the designer is not always what is achieved on site. Cost is another area that can be problematic. The cost of the external envelope can be influenced by many factors including design complexity, or changes in the design and the coordination of the building envelope to accommodate structural support, glazing or louvres, for example. The overall installed costs must be considered, rather than solely the square metre rate of a material.

Until now there has been a lack of a system-based approach to the design and specification of lightweight infill walls. Instead, each component of the wall was offered by different manufacturers with each providing data relevant only to their element of the system. System solutions can, however, take away the uncertainty of specifying building envelopes and reduce the risk of not meeting building regulations, performance or cost requirements - helping specifiers meet the challenges of designing the external building envelope. EOS, as part of the Etex Building Performance group of companies, can call upon the expertise of three leading lightweight construction brands - Siniat, Promat and EOS. The combination of expertise in drylining, external sheathing and steel framing systems, as well as passive fire protection, means that Etex Building Performance is uniquely positioned to bring these elements together to create a range of tested and warranty external Thruwall® systems. After having completed rigorous fire, acoustic, weathering, airtightness and mechanical testing - our all Thruwall® systems are supported by a 30-year warrantee. They combine BBA certified, non-combustible A1 external sheathing, engineered steel framing systems and internal wall linings - meeting building performance requirements for fire, thermal, weathering, acoustics and airtightness all in one certified solution.

Steel framing systems do not suffer from shrinkage or unpredictable differential movement, which affects other forms of construction. It is not predominately a single sector or single solution technology and can add value to a project 'up-stream'. The adaptability of steel results in systems being used in a variety of ways and forms to meet the demands of low, medium and high-rise developments across all construction sectors. Offsite system manufacturers are operating in exciting times for the built environment and there has never been a better time to capitalise on the raft of benefits that factory-based offsite technologies can deliver.