SIPs are the affordable, superior alternative.

All market comparisons are for a point in time reference (May 2021) and float in accordance with volatile commodity pricing for the various raw materials and design specifics. SIPA encourages readers to consult NAHB for current lumber pricing.

Fundamental economics dictates that a stable commodity price must be approached by balanced supply and demand factors. Large fluctuations on either end can send a commodity crashing or increasing rapidly. Unfortunately, nobody is yelling “timber!” within the lumber industry as it is playing out quite the opposite. Lumber has seen unparalleled demand since the Covid-19 pandemic, affecting prices for homebuyers and construction professionals. The housing market, while volatile, has seen sharp increases that have only furthered the housing crisis in many parts of the country. According to the National Association of Home Builders (NAHB), lumber projects increased by $34k (+240%) from April 2020 for a standard 2,000 sq. ft. home. [1]

How does the framing factor impact the energy required and the cost?

Now more than ever. To better understand the way this market shift has impacted the price of a home, let’s explore the lumber needs of a project or the framing factor. A standard home utilizing 2x4s has a 24% framing factor with studs placed every 16 inches. The fiberglass, or insulation of choice, is installed into the frame resulting in an insulation gap every 16 inches with every stud. In other words, 24% of the home’s frame is solid wood (with increased energy leakage via thermal bridging) leaving only 76% of the wall frame with insulation. [2]

By contrast, SIPs typically have an average 5% framing factor meaning 95% of the wall has insulation. [JA1] SIP facers carry the load and are manufactured specific to the project and can be delivered to the jobsite as large as 8x24 feet. This eliminates the need for excess lumber as studs, and labor costs are also reduced because insulation and sheathing are included in each panel. SIPs have an insulating foam core sandwiched between oriented strand board (OSB) facers.

With a framing factor of 5%, SIPs use less lumber while creating a more efficient building envelope. The cost of SIPs, by comparison to the $34k lumber package increase, has risen only by approximately $8k (~25%-30%) for a standard 2,000 sq. ft. home over the same period. (These comparisons are for a point in time and float in accordance with volatile commodity pricing for the various raw materials and design specifics.)

If you are thinking about building, the takeaway is that stick-framing project costs have increased by 240% while SIPs have only increased by much less for a better performing, insulated solution which is faster to install.

Understanding the framing factor of a home helps conceptualize the impact lumber markets have had on building and constructing homes in 2021. This concept is one of the many reasons SIPs make a cost-effective building choice today. For a comprehensive explanation of other factors effecting building costs and labor needs, download SIPA’s brochure Best Practices: High-Performance SIP Building Envelope. Additional topics covered in the brochure include thermal bridging, R-value, quality insulation installation, and reduced HVAC requirements.

SIPA is the source for design professionals, builders and researching homeowners to find training resources and materials on the superior benefits of structural insulated panels. Visit for more information on the lumber market forecast.


[1] Solving the Lumber Crisis, NAHB.

[2] Design Best Practices 1 – High-Performance SIP Building Envelope