OSB Structural Insulated Panels

OSB SIPS (Oriented Strand Board Structural Insulated Panels) are high-performance building systems that consist of an insulating foam core sandwiched between two sheathing layers of oriented strand board. SIPs contribute both insulation value and structural strength to the wall. Walls and ceilings made of SIPs can be constructed quickly by assembling the pre-manufactured panels. The foam core can be made with expanded polystyrene foam (EPS), extruded polystyrene foam (XPS), polyisocyanurate foam, polyurethane foam, or be composite honeycomb (HSC). Vapor barriers are not required in SIP homes, but an interior wall covering must be added.

Check the claims of enhanced R-value that may be overstated. The insulation value of a SIP is higher than a stud wall of the same thickness, due to reduced thermal bridging, but some SIP panels are too thin to be what you need for a super-insulated house such as a Passive House in a very cold climate. Look for panels that are 8 to 10 inches thick for an advanced home in the northern USA or southern Canada climate. Also, consider the type of insulation material - what is it made of (polyurethane, polyisocyanurate, plant fiber composites, etc.), and how low is its off-gassing of volatile organic compounds (VOCs).

OSB SIPs provide an insulation layer without any thermal breaks or bridges (continuous insulation). They also make air-sealing of the building easier, by simplifying on-site construction and having fewer gaps to seal. Depending on what kind of insulation is in the core of the SIP, it can have high insulating value and low VOC emissions. OSB is thought to be more environmentally friendly than plywood since the shredded wood pieces can be made with smaller tree sections from a variety of tree species. Plywood manufacturing requires larger, more mature trees.

The first structural insulated panel was developed in Madison, Wisconsin by Forest Products Laboratory (FPL).