Structural insulated panels (SIPs) are high-performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are made by sandwiching a core of rigid foam plastic insulation between two structural facings, such as oriented strand board (OSB). Other skin materials can be used for specific purposes. SIPs are manufactured under factory controlled conditions and can be custom designed for each project. The result is a building system that is extremely strong, energy-efficient and cost effective. Building with SIPs will save you time, money and labor.

SIP homes go up much faster than traditionally framed buildings. A properly trained SIP installation crew can cut framing time by 55 percent compared to conventional wood framing, according to a third-party study conducted by R.S. Means. Panels are manufactured as big as 8-foot by 24-foot, so entire wall and roof sections can be put up quickly, reducing dry-in time. SIPs are ready to install when they arrive at the jobsite, eliminating the time needed to perform the individual jobsite operations of framing, insulating and sheathing stick framed walls. Electrical chases are typically provided in the core of panels, so there is no need to drill through studs for wiring.

Builders can save money through decreased construction and labor costs. A high-performance building envelope often allows HVAC equipment to be downsized and ductwork to be minimized. Builders can also significantly reduce jobsite waste disposal and temporary heat during construction. Homeowners that incorporate other energy-efficient features into a SIP home can see utility savings of 50 percent or more. In a 2021 example for a typical 2,000 sf home, using SIPs saves over $16,000 in eliminated 2 x 4 raw material costs alone due to the high costs of lumber versus OSB used for SIPs.

SIP construction is recognized by the International Code Council body of building codes, which are used by most jurisdictions in the U.S. SIPs are also approved by the State of Florida for High Velocity Hurricane Zones (HVHZ).

For residential buildings, specific construction practices for SIP wall systems are included in Section R610 of the 2018 International Residential Code. For applications beyond the scope of Section R610, the building inspector will typically require a licensed engineer or architect to approve the building plans prior to construction. An engineer’s approval is always required in high wind areas, high seismic zones and commercial buildings.

R-values for SIPs depend on the thickness of the SIP and the type of core material that is used. See SIPA’s R-value chart for the minimum R-values of commonly available SIPs.

Static R-values, like those included in the chart, rate the effectiveness of insulating material. However, they do not accurately describe how products perform in a real-world setting. When fiberglass or other types of insulation are installed, they are installed around structural members made of wood or metal that have very poor insulating value. Field-installed insulation materials are also prone to installation imperfections.

The Department of Energy’s Oak Ridge National Laboratory has studied and tested the performance of entire wall assemblies in large sections. The resulting whole-wall R-value data reveals that a 4-inch SIP wall rated at R-14 outperforms a 2 × 6 wall with R-19 fiberglass insulation. For more detail, download the free SIP Design Best Practices 1: High-Performance SIP Building Envelope.

Plumbing should not be located in exterior SIP walls because of the possibility of condensation or supply lines freezing in cold climates. During the design phase of the project, all plumbing should be relocated to interior walls.

If plumbing must be located on an exterior wall, it is recommended that a surface chase be installed on the interior of the wall to conceal plumbing. Another option is to construct a small section of the wall using conventional wood framing that can be used to run plumbing. Plumbing penetrations such as drain water vents (DWV) can be placed through SIPs if they are thoroughly sealed to prevent air infiltration.

The construction of a SIP home or commercial building begins with the construction documents. Once the construction documents are in the hands of a SIP manufacturer, dealer/distributor or design professional, they are converted to SIP shop drawings that give the dimensions of each individual panel.

The shop drawings are reviewed by the builder, engineer, the building owner and other involved parties. Once the shop drawings are finalized, the SIPs are fabricated and shipped to the jobsite for installation. For more information, watch the half-hour educational videos on SIP Order Process and SIP Layout Drawings. For a more complete process summary, download the free brochure Designing with SIPs: DESIGN CONSIDERATIONS.