SIPS Structural Performance

SIPCO SIPs are engineered for loadbearing capability, racking resistance and wind loading per the test results specified within the SIPCO BBA certification.

Structural Insulated Panels (SIPs) are high-performance, lightweight, building panels for use in various building types. Manufactured offsite under closely controlled conditions, systems are custom-designed for each application. The result is a high-strength, energy-efficient and cost-effective solution. There are two fundamental applications for SIPS; full structural and infill walling for a concrete, steel or engineered timber frame.

Why Us
  • BS 5534 : 2003+A1: 2010 Code of practice for slating and tiling (including shingles)
  • BS 5628-3 : 2005 Code of practice for BS EN 338 : 2009 Structural timber — Strength classes
  • BS EN 594 : 1996 Timber structures – Test methods. Racking strength and stiffness of timber frame wall panels
  • BS EN 846-6 : 2000 Methods of test for ancillary components for masonry — Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)
  • BS EN 1995-1-1 : 2004+A1: 2008 Eurocode 5 — Design of timber structures — General — Common rules and rules for buildings
  • BS EN 1995-1-2 : 2004 Eurocode 5 — Design of timber structures — General — Structural fire design
  • BS EN 1996-2 : 2006 Eurocode 6 — Design of masonry structures — Design considerations, selection of materials and execution of masonry the use of masonry — Materials and components, design and workmanship

High Structural Performance: Building with SIPs

SIPs are created by auto-adhesively sandwiching two high-density facings (typically Orientated Strand Board) with a low-density, cellular foam core. The rigid foam polyurethane core bonds to the structural skins via an injection process. SIP walls can bear considerable vertical and horizontal loads with reduced internal studding. High structural performance is essential to the SIPs load bearing ability – high loads are transmitted by the relatively light elements, transferred to the ground by the OSB skins held in position by the insulation core.

SIPCO operates strict quality control procedures to ensure certainty in performance, quality and consistency. In all cases, the SIP will be engineered for load-bearing capability, racking resistance and wind loading per the test results specified within the SIPCO BBA certification.

SIPCO panels undergo stringent testing procedures to assure performance. Testing includes loading panels with a uniformly distributed load (UDL) to measure strength and deflection between two supports, axial loads centrally and eccentrically placed, racking loads and shear and bending loads on the panel joints. The strength of the joints between the individual panels is such that panels can potentially span over openings, supported by the panels on each side.

The localised concentration of loading is achievable by incorporating additional timber at the panel joints. However, with careful detailing, much of this is avoidable. Tests have shown that the panels have a very high ultimate bending strength. Deflection, calculated as per our Design Guide, is the governing criterion in design. This increases user confidence that safe working loads are well over standard deflection limits.

Axial loading tests on panels 100mm thick, 2.4m in height and 2.4m in width were seen to fail at a load of 440kN/m. Using a factor of safety of 2.0 panels can support a vertical load of 90 kN/m. These loads are significantly higher than the average foundation loading of a typically constructed two-storey house.


Additional information about SIPs structural performance can be found within the Structural Timber Association SIPs Technical Bulletin 1.