Structural Insulated Panel

Structural Insulated Panel, known as SIP or SIPs is a high-performance strong prefabricated building panel for walls, roofs, foundation walls, and floors, in residential and commercial buildings. Greensmart’s panels are typically made using expanded polystyrene rigid foam insulation (EPS) sandwiched between two oversized structural skins of oriented strand board (OSB), and other exterior surfaces are also available to meet your needs. The result is a building system that is very strong, predictable, energy efficient, and cost effective.

Why OSB?

OSB is manufactured from waterproof heat-cured adhesives and rectangular shaped wood strands that are arranged in cross-oriented layers, similar to plywood. This results in a structural engineered wood panel that shares many of the strength and performance characteristics of plywood. OSB panels are environmentally smart and manufactured from a wide range of fast-growing trees and shrubs once considered waste by the lumber industry.

Why expanded polystyrene?

Expanded polystyrene is a polymer impregnated with a foaming agent which, when exposed to heat, creates a uniform, closed-cell structure highly resistant to heat flow and moisture penetration. In addition to its excellent insulative properties, EPS resists compression and bending, as well as providing good cushioning properties. EPS is very resistant to moisture retention and is much less combustible than wood. Polystyrene is also a safe, non-toxic, clean product and for these reasons is approved for and widely used in the food packaging industry.

Installation

SIPs construction relies on careful planning and design prior to delivery and site assembly. Greensmart offers pre-designed house packages with wall and roof panels of standardized dimensions to help control costs. For custom designs, a completely customized panel layout must be produced. Greensmart uses computer controlled equipment that transfers panel cutting instructions directly from digital CAD (computer aided design) drawings.

The panels are then tarped and shipped to the jobsite for assembly. Ideally, panels are offloaded and stacked in the exact reverse order needed, so that no sorting or shuffling is required. After the bottom plate is attached to the perimeter, placement of the wall panels begins. Panels weigh approximately three pounds per square foot, so panels can be designed light enough to be carried and set by hand.

Exterior walls for most houses can be erected in less than a day. Nails and adhesive foam are used to fasten the panels to top and bottom plates, and to make vertical connections. Review the shop drawings in detail, as it explains how many nails will be needed for secure connections. Long screws are used for SIP corner connections.

Walls must be properly braced and plumbed, and interior walls are typically constructed with conventional framing. Beams that carry roof loads may require stud supports incorporated into wall panels, to carry point loads downward. This is shown in the engineered shop drawings. Heavier roof panels are usually set in place with a crane.

To take full advantage of SIPs insulating capacity, care must be taken to seal all joints properly, but the relatively small number of connections makes this easier to accomplish. Spray polyurethane foam, gaskets and caulking is used to fill any voids or gaps.

Some trades may find their work made simpler by SIPs construction. For instance, drywall and siding installers need not worry about locating studs. Others, such as electricians, may need to make special accommodations. Most panels include a formed chase in the core for electric wiring, but insets for boxes and additional channels must be mechanically routed, then resealed with aerosol foam. Generally, best practices for plumbing design route pipes through interior walls, but if placement of pipes in near exterior walls is necessary, significant routing and foaming may be required.