Currently, the enclosure of the Queen of Zero - a custom single-family rebuild in Maryland and the 2024 JLC Case Study home - is taking shape. The exterior shell is being built from energy-efficient structural insulated panels (SIPs), each consisting of two roughly 4-by-9-foot sheets of OSB sandwiching a core of EPS insulation. The SIPs at Queen of Zero were manufactured by Acme Panel company and shipped flat to the site.
Over the past decade, SIPs have become my company’s preferred building strategy for new homes aspiring to a net zero standard. Yet, despite the many advantages and proven track record, a very small percentage (1% to 2%) of all homes in the U.S. are built with SIPs.
So why, with their decades-long track record of success, aren’t more homes built with SIPs?
Panelized Construction – Myth vs. Fact
Widespread adoption of SIPs has been hindered, in part, by decades of misinformation across the homebuilding industry. Take these oft-cited claims, for example:
Cost
Myth – Building with SIPs costs significantly more than traditional stick construction.
Fact – In my experience building high-performance custom homes, the upgrade to SIPS adds about 2 to 3% to the construction budget. Other builders estimate a cost saving using SIPs. The Structural Insulation Panel Association (SIPA) offers a free estimating tool to compare the cost of panels versus conventional construction. And because SIPs have superior insulating properties, the initial upcharge can be offset by future reductions in utility costs.
Technology
Myth – SIPs are a new, experimental construction technique that has not been significantly tested.
Fact – The first foam-core SIP was developed in 1952 by Alden B. Dow, (son of the founder of Dow Chemical Co. that produced the foam), using panel designs pioneered by the Forest Products Laboratory in the 1930s. SIPs became popular as infill panels for timber-frame homes in the 1970s, and the SIP industry has grown to 12,000 housing starts per year, as well as thousands of commercial buildings, such as 7-11 convenience stores and Benihana restaurants, according to SIPA.
The IRC requires that SIPs meet ANSI/APA PRS 610.1, and most quality panel manufactures issue Evaluation Service Reports showing compliance to these required standards.
Installation
Myth 1 – SIPs are complicated to install and require specialized equipment and training.
Myth 2 – SIPs are super easy to install for just about anyone – including DIYers.
Fact – Although SIPs are not inherently complicated, panel installers should receive SIP training and oversight by a registered SIP builder, regardless of their prior construction experience. In addition to typical framing tools, one or more SIP-specific tools, such as the SIP Groover and 2 Person Hot Wire Handles, may be required for a job. Many panel manufacturers offer training, on-site consultation, and referrals to trained installation crews. The SIPA website offers a wealth of best practice resources, and Al Cobb’s SIP School offers in-person and online courses.
Customization
Myth – Factory-built panels are best suited for “production style” homes with minimal architectural details.
Fact – The size, location, and composition of each structural panel is engineered specifically for a particular set of architectural drawings, and therefore customization is built into the process. There may be some designs that are not particularly suitable for panels, but I personally have not come across any limitations to date.
We do sometimes opt for manufactured trusses rather than SIP panels for the roof, primarily due to the aesthetics when there is an abundance of framing angles, such as on the traditional pitched roof of a Queen Anne Victorian.
SIP floors are also not recommended above living space due to the percussive noise transfer, so we frame decks conventionally and use GreenFiber Sanctuary blown-in cellulose for interior sound attenuation.
Mainstreaming Panel Construction
In addition to correcting these common misconceptions, SIP advocates must also overcome the typical hurdles associated with widespread technology adoption. The construction industry can be particularly averse to change, as many builders survive on slim profit margins and mistakes can be costly. Thus, any strategy to increase market share should include capacity-building support to reduce risk and grow competencies—such as training and education programs, mentorship, building communities of practice, and on-site monitoring and technical assistance programs.
Yet, despite the hurdles, there appears to be growing optimism among people in the SIP industry. Panel manufacturer and podcast host Gabriel Grossman of Preflex Inc. predicts SIPs will “go mainstream in the next 10 years” due to the growing demand for net zero homes, persistent shortages of skilled construction labor, desire for built-in resiliency to rebound from climate disasters, and a shift toward off-site technology to speed up production and help solve the housing crisis.
SIP Lessons From Queen of Zero
On the first day of SIP install at our Queen of Zero project, a few of the framers, who were unfamiliar with panel construction, complained that site supervisor Matt Kulp, a veteran SIP builder, was being “too picky,” and they walked off the job. Good riddance, I suppose, since building high-performance is all about fastidiousness. And let’s face it, those guys probably have their pick of any number of sites to show up at every day, as their services are in high demand. Framing is difficult, back-breaking work, and the “less picky” jobs may make the day go a bit smoother. But this episode does underscore the tremendous learning curve for our boots on the ground. In some cases, it’s not just a lack of knowledge that stands in our way, but also an unwillingness to engage in the learning process.
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