SIP stands for Structural Insulated Panel, which is a good description of what this building material is. It’s a manufactured panel that has both structural strength and insulation in one unit. Basically, it consists of two sheets of facing material (typically OSB) sandwiched around a layer of rigid foam insulation.
Structurally, SIPs produce a stronger, safer building than an equivalent ‘stick-framed’ one. The manufacturing process bonds the entire sandwich together evenly, forming a single unit that is stronger than the sum of its parts. As a result, the whole panel can support loads at any given point – as compared to a conventional ‘stick-framed’ wall, which has studs at regular (usually 16”) intervals. Imagine a tree falling on your house: if your walls have studs at specific intervals, with sheathing on the outside and wall finish material such as drywall on the inside, there will be stronger and weaker points in those walls. Chances are much greater that the weight of the tree will fall on a weaker point, causing significant damage. If your house is built of SIPs, the strength of the walls and roof is continuous, and the tree is less likely to breach the envelope of your home.
SIPs also help reduce energy use and, thereby, energy costs. Homes built of SIPs provide better thermal protection than most other building methods. The insulation is consistently of the same thickness (and R-value) throughout, and there are far fewer breaks in the insulation. In a typical stud-wall home, the insulation is interrupted at every stud, and each stud acts as a conductor of heat and cold. Depending on the type of insulation used, there is ample opportunity for gaps and coverage variations in site-applied insulation as well. In a SIP home, the insulation is interrupted only at openings (windows and doors) and occasionally at load-bearing post locations between some of the panels (posts are not necessary at every panel joint). And because SIPs are built in a factory environment, they are much more uniform in size, shape, and quality than pieces of lumber individually cut and nailed in place on a building site. As a result, the entire building is much more consistent in its ability to maintain air temperature.
Your home’s job is to keep you safe, secure, and comfortable. A SIP home, even though it may look no different from more conventionally-built homes when it’s finished, excels at this job. If the prospect of living in a high-performance home appeals to you, a SIP home is an outstanding choice.
For more information on this construction method, visit the Structural Insulated Panel Association website.