Structural Insulated Panels
Structural insulated panels, or SIPs, are an alternative building technology, consisting of prefabricated, insulated units, assembled in modular fashion on the construction site. SIPs are energy efficient and allow for faster construction times than conventional framing methods. The panels can be used for wall and roof construction. Panel assembly doesn't require the level of skill that frame construction does, but the design and prefabrication are more demanding, and preparation of foundation and site work needs to be precise to match the manufactured product.
SIPs are constructed with a foam layer -- polystyrene or polyurethane -- placed between two sheets of Oriented Strand Board, plywood, or fiber-cement. When the foam is bonded to the rigid skins, web-and-flange structural strength is created, similar to an I-beam, with the capacity to resist a variety of pressures, including seismic forces and high winds. Overall, SIPs are strong, durable and more airtight than frame construction. Meticulous engineering design is a major part of the success of panel construction.
While faster to assemble than frame construction, SIPs are initially more expensive, and customized details add to the cost. Panel construction is less flexible than frame type, and on-site changes are more difficult to manage. Electrical and plumbing work may not be easily integrated with the panels, and ventilation systems need to be carefully incorporated. Warranties for materials may not be available, if the manufacturer isn't familiar with panelized construction. Building codes don't yet contain prescriptive language for SIPs.
Homemade SIP Wall Panels
SIPs are a challenging project for the handyman. The units are structural, usually manufactured with the help of digital technology, and relatively new for many sub-trades, which may need to alter standard practices to accommodate the panel construction. Building officials usually implement a longer review and approval time for SIP homes, with additional inspections. Generally, engineering approval is required for construction of SIPs, adding more complexity to the project.