Structural Insulated Panels (SIP)
A SIP is an energy efficient structural wall system that is manufactured with a core of Styrofoam laminated to oriented strand board (OSB) or plywood. Panels are available for walls, roof and floor systems. Special below grade panels are also available for super insulated lower levels in the ground.
Frequently asked questions (FAQ)about Structural Insulated Panels
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A Structural Insulated Panel (SIP) consists of a layer of expanded polystyrene foam sandwiched between two layers of oriented strand board (OSB) sheathing. The entire assembly is bonded together with adhesives resulting in an incredibly strong and rigid building component. In fact, SIP walls are typically 2-1/2 times stronger than conventionally framed walls.
Homes built with SIPs can be built much faster than their conventionally framed counterparts. The reason for this is two-fold. First, since SIPs come in 4' widths the walls themselves go up quickly. Second, when using SIPs you combine the installation of framing, sheathing, and insulation into a single step.
Perhaps the most compelling reason to choose SIPs over conventional framing is the vastly increased energy efficiency of SIP homes. There are three primary factors that allow SIP homes to out-perform conventional framing in this area.
The large, un-interrupted expanses of EPS foam in panel walls greatly reduces air infiltration rates. That means conditioned interior air stays in and unconditioned exterior air stays out.
In conventionally framed walls the studs create a "thermal short cicuit" in the insulation every 16". With SIP walls these thermal short circuits are far fewer. In fact they only occur at corners and where dimensional or engineered lumber is needed to carry point loads through the walls to the foundation system.
The effectiveness of fiberglass batt insulation is dependent to a large extent on the quality of the installation. If the installers do not take adequate care when insulating around wiring, pipes, and electrical boxes the effectiveness of the entire system can be severely compromised. With SIPs there is less potential for human error. The insulation is already in place and permanantly bonded to the OSB sheathing. Low expanding foam is used around all window and door openings and electrical boxes to complete the system.
If you're looking for yet more reasons to build with SIPs consider this:
The same characteristics that make SIP homes so well insulated also make them substantially quieter than conventionally framed walls.
Since the rigid foam insulation doesn't allow air movement through the walls SIP homes are more resistant to fire than conventionally framed homes.
SIP homes require about 30% less dimensional lumber than conventionally framed homes. This greatly reduces the demand on our precious forest resources.