Last year, the Royal Institute of Chartered Surveyors revealed that the number of European commercial properties carrying a sustainability certification mark increased by 64% in the period 2013 to 2015. In the UK alone, 2,422 properties were BREEAM certified with a further 7,343 pre-certified.
With this ongoing demand for energy efficient buildings, it makes sense for specifiers and contractors to consider new and potentially more cost effective ways of delivering excellent fabric performance in cladding applications. One increasingly popular option is Structural Insulation Panels (SIPs).
The design and energy performance advantages of SIPs were discussed in the previous article in this series. Many of these benefits are not only relevant but enhanced in cladding applications. For example, site waste is often a major issue on multi-level cladding projects. As SIPs are designed and manufactured to each building’s precise specification, on-site adjustments and off-cuts are virtually eliminated, saving both time and space on the site. In addition, deliveries can be reliably scheduled in advance, allowing effective planning on large-scale projects.
The lightweight design of the panels is another significant advantage. A small team of dedicated operatives can typically install SIPs with either light lifting equipment or a mast climber, reducing the need for scaffolding. The exterior OSB or particle board facing also forms a flexible substrate, supporting most façade systems.
In cladding applications, SIPs can either be fixed ‘in-board’ within the apertures of a concrete or steel frame or ‘out-board’, sheathing the structure.
For in-board applications, SIPs are typically secured to the floor and ceiling of the structural frame with a combination of dead bolt-fixings and angled cleats with slotted fixing connections. These slotted connections allow the panels to move with the expansion and contraction of the structural frame. If this approach is used, high performance insulation should also be fixed to the external face of the structural floors on each level in order to reduce thermal bridging.
In out-board applications, SIPs are secured to the structural frame at floor and ceiling level using dead bolts fixed through the panels to angled cleats typically at 400 mm centres. The fixings at ceiling level are again slotted to allow for differential movement.
The out-board approach offers several notable advantages for end users. The exterior application helps to preserve internal space and also limits thermal bridging through the structural frame without requiring additional insulation.
SIPs are suitable for both new-build and refurbishment cladding applications. In the next couple of articles we’ll look at how they’ve been used across a range of projects.