Originally published in the Industry Trends section of Buildings Products Digest.
The vast majority of builders in the U.S. now face necessary and demanding energy codes. The new 2021 International Energy Conservation Codes (IECC) are now in play with many states moving quickly toward adoption. As of September 2022, thirty-eight (38) states have adopted IECC codes based on the 2018 IECC or higher, and another ten (10) enforce the 2015 IECC or higher. These states account for a whopping 94% of the United States population. These numbers make one thing clear – Builders, Designers, and Owners need to work quickly to adopt the most efficient building methods in order to achieve today’s energy codes.
SIPs - A Simple & Efficient Choice
The following article was originally published in the Industry Trends section of Building Products Digest and is a great overview of how SIPs are a simple and efficient path to exceed energy codes and create superior structures.
As a Lumber & Building Material (LBM) dealer, your builder customers are always looking for ways to meet the tough requirements of ever-stricter energy codes. Among their challenges are how to better seal the building envelope against air leaks and provide continuous insulation. California’s Title 24 Building Energy Efficiency Standards, which are likely to find their way into other state codes in the coming years, specifically require that “all joints, penetrations and other openings in the building envelope that are potential sources of air leakage shall be caulked, gasket, weatherstripped or others sealed to limit infiltration and exfiltration.”
The IECC likewise sets tough standards against air leakage. As of the 2012 IECC, builders have had to demonstrate code compliance with a blower door test that achieves three to five air changes per hour at 50 Pascals of pressure (ACH-50), depending on the jurisdiction.
Energy codes focus on creating an airtight envelope as air leakage accounts for up to 40% of a home’s energy load according to the National Association of Home Builders.
Meeting these code requirements with traditional building methods like stick framing requires builders to undertake heroic measures to search out and seal all gaps using caulks, expanding foams, and other sealants. Since homes, apartments, and other light construction have hundreds of interfaces between framing members, this is no small feat.
Airtight Building Envelope Made Simple
When builders ask your sales staff for ideas on better sealing the envelope, one of the best recommendations they can make is to use inherently airtight systems like structural insulated panels (SIPs) or insulated concrete forms (ICFs).
Testing by the U.S. Department of Energy (DOE) shows that SIP construction is about 15 times more airtight than stick framing. DOE’s Oak Ridge National Laboratory (ORNL) found that the air leakage in a SIP structure was only 8 cu. ft. per minute at 50 Pascals compared to 121 cu. ft. per minute for a stick-framed building.
One reason for the superior airtightness is SIPs arrive at the jobsite in large, ready-to-install sections. Imagine a home with a 20-ft. wall section. With conventional stick framing, there would be 15 vertical cavities needing insula-tion along that wall (assuming 16-in. O.C. spacing of studs). With fiberglass insulation, those cavities have hard-to-seal gaps along the right and left side of each batt. Yet one 20-ft.-long by 8-ft.-tall SIP could comprise that entire wall, with gaps to be sealed limited to the panel ends, top and bottom. Another reason that SIPs are so airtight is because the connections are sealed with mastic. Each joint has multiple beads of mastic that work to stop the movement of air through the panel joints.
But, does SIPs’ airtightness in lab tests hold up in the real world? Yes. In one powerful indication of this among thousands of SIP homes built throughout the U.S., California’s Clarum Homes built a 3,300-sq. ft., single-story home at a mid-price range using SIP walls and roof, that was rated at 0.2 ACH-50. That’s up to 25 times more air-tight than the IECC 2012 requirements, surpassing even the Passive House standard of 0.6 ACH-50.
Outstanding Insulation Performance
In addition to their ability to create a tight building envelope, SIPs also offer superior thermal resistance to other structural and insulation assemblies. For example, ORNL tested the “whole-wall” R-values of SIPs and stick framing, taking into account thermal bridging through structural members. The SIP wall built with 3.5-inch thick foam core had a dramatically higher R-value of 14.09 compared to 9.58 R-value for a 2x4 stud wall at 16 inches O.C. and fiber-glass insulation—that’s 47% better thermal resistance for the SIP. A key reason SIPs far outperform stick framing is that SIPs offer continuous insulation across their height, width, and depth and have far fewer thermal bridges.
What’s In It for Dealers?
SIPs offer builders many advantages, but dealers may wonder about losing out on sales of insulation and sealants. Yet, it’s important to remember the value LBM pros provide. When Amazon.com announced it would sell building products, many LBM dealers feared they would suffer the same fate as book publishers by being under-cut on price. But savvy dealers realized that while Amazon might be able to sell builders cases of caulk cheaply, Amazon will never be able to compete with their building expertise.
So, when a builder expresses frustration about the challenges with meeting ever tighter building codes, you can try to double down by selling him more sealants or set yourself apart with real solutions such as providing insights on SIPs and other advanced building methods, which helps build loyalty over online sellers.