Structural Insulated Panel Systems (SIPS)

 SIPS are a modern alternative to traditional timber framed construction and function as the structural element for walls, roofs, and suspended floors. They consist of two outer layers of Oriented Strand Board (OSB) sandwiched around an Expanded Polystyrene (EPS) core. A variety of construction and design advantages are provided by the system such as superior eco-friendliness, acoustic and thermal insulation, fire and termite resistance, as well as an efficient construction procedure.

With a growing emphasis in the residential and architectural construction industry on alternative eco-friendly, versatile and economical building materials – Structural Insulated Panel Systems (SIPS) are one such example. Comprising two timber panels of Oriented Strand Board (OSB) and an internal layer of Expanded Polystyrene (EPS), the favourable insulating and acoustic properties of the material combined with the fast construction and site-adaptability make SIPS an attractive alternative to standard timber stud walls and also for use in roofs and floors.

Structural Insulated Panel Systems (SIPS)
Structural Insulated Panel Systems (SIPS)

In the fabrication of Oriented Strand Board (OSB) 85-90% of the log can be used. Compared with conventional milling, where the recovery is typically 50-70%, the board makes use of timber which would be otherwise discarded.

Combining two layers of the impact resistant and high strength OSB with a thick insulating layer of Expanded Polystyrene (EPS), the resultant SIPs are strong, quick to erect and well suited to the residential construction industry. The panels are termite resistant and outperform timber stud and metal framed construction in both acoustic and thermal ratings. Fire ratings of 60/60/60 and up to 90/90/90 can be achieved when installed with the appropriate cladding.

SIPs can be used in place of timber stud walls, roofs and suspended floors. The panels are typically pre-fabricated providing opportunity for significant reduction in on-site construction times and minimising waste. When used in walls, the panels are typically full height and are spliced together side by side using twin studs or SIP splines. Twin studs are generally used in locations where additional strength is required.

Methods for fixing other timber members to SIPs are similar in nature to standard timber construction, making the SIPS a natural alternative for structural designers. Panels have strength sufficient to be used as bracing walls. However, some additional fixings or studs may be required for stronger bracing walls. Panels are available in various thicknesses, and the design and specification of the panels relies heavily on manufacturer-provided design tables. Australian suppliers must ensure their SIP product complies with Australian testing standards and code requirements.

Standard SIP internal chasings are provided to enable electrical services to be installed through the insulated panels with ease. As the OSB facing of the panels is load bearing along its full length, it is important that the panels are not cut without engineering design.

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