Structural Insulated Panels (SIPs)

SIP is an acronym for Structural Insulated Panel.

SIPs have been in use for more than 60 years in the United States where more than 5% of domestic property is constructed with them.

SIPs consist of 2 outer skins of ply or OSB (Oriented Strand Board) bonded under pressure and under strictly controlled conditions to both sides of a rigid foam core. We manufacture SIPs from OSB3, the structural and water resistant version of OSB with the core made of Expanded Polystyrene EPS.

These components, when bonded together, form a composite that is very much stronger than the sum of its parts with one face in tension and the other in compression while the core resists shear and buckling. SIPs act like an ‘I’ beam. The foam core acts as the web with the OSB3 acting as the flanges of the beam. As with an I-beam the thicker the SIP the stronger it is.

SIP structures are many times stronger than timber frame ones. They have survived the 1993 Kobe earthquake in Japan and hurricanes and tornadoes in the United States when surrounding brick and timber frame houses around them have been destroyed. They have been dislodged by floods and have floated down rivers intact and survived mature trees falling on them suffering just superficial damage.

SIP buildings are far superior to timber frame buildings with regard to sheer resistance, flexural strength, compressive resistance and resistance to uplift.

SIP structures do not have draughts, do not suffer from compression and settling of the insulation as do buildings with glass fibre and mineral wool insulation. If glass fibre insulation contains as little as 2% moisture its insulating properties can be reduced by as much as 40%. SIPs are unaffected. Nor does the ability of Expanded Polystyrene to insulated degrade over time. It will be as effective in 20 or 50 years time as it was when first built.

Environmentally Friendly

SIP components are also environmentally friendly. Expanded Polystyrene doesn’t employ either CFC’s or HCFC’s in its manufacture.

OSB3, is manufactured from precision cut slithers of wood from plantations of quick growing trees such as aspen and southern yellow pine. It uses all the timber from the tree including side branches and does not require slow grown timber so its production does not require the cutting down of environmentally sensitive forest trees. It now accounts for about 50% of the plywood market in the USA thereby reducing that industries effect on softwood and hardwood forests both in the USA and from tropical rainforests.