The History of SIPs

SIPs may be revolutionizing the structures of buildings but they are not new to construction and design. The earliest concept of structural sandwich‑panel technology was developed in the 1930s at the Forest Products Laboratory (FPL) in Madison, Wisconsin. FPL engineers proposed that plywood and hardboard sheathing could take a portion of the structural load in wall applications. Their prototype was used to construct test homes that continued to be monitored over thirty years, then disassembled and reexamined. During this time, FPL engineers continued to experiment with new designs and materials.

Famed architect Frank Lloyd Wright used these innovative structural insulated panels in his affordable Usonian houses built throughout the 1930s and 1940s. Wright attempted to incorporate beauty and simplicity into relatively low‑cost homes. Some of the walls in these houses consisted of three layers of plywood and two layers of tar paper but lacked insulation.

SIPs advanced in technology when one of Wright's students, Alden B. Dow, brother of the founder of Dow Chemical Company, created the first foam core SIP in 1952. Dow, concerned about energy efficiency, was dismayed by the lack of insulation in the Usonian homes. He experimented with the engineering of structural panels with insulation and is now generally credited with producing the first structural insulated panels. His SIP houses were built in Michigan using panels composed of 1⅝ inch Styrofoam cores and 3/16 inch plywood facings for the load-bearing walls and installed over roof framing on 42 inch centers. You can still find several of these houses today, and yes, they are still lived in!

By 1959 the Koppers Company converted an auto production plant in Detroit into a SIP production facility and in the 1960s began the first manufacturing effort of structural insulated panels, resulting in the production of SIPs as we know them today.

The Structural Insulated Panel Association was founded in 1990 to provide support and visibility for those manufacturing and building with this emerging building technology. Not long after, SIPs saw the development of advanced computer aided manufacturing (CAM) technology. Using these systems, computerized architectural drawings (CAD drawings) can be converted to the necessary code to allow automated cutting machines to fabricate SIPs to the specific design of a building. CAD to CAM technology has streamlined the SIP manufacturing process, bringing further labor savings to builders.

Today SIPs offer a high tech solution for residential and low rise nonresidential buildings. Advances in computer aided design and manufacturing allow SIPs to be produced with amazing accuracy to deliver flat, straight, and true walls. SIPs are now made with a variety of structural skin materials, including oriented strand board (OSB), treated plywood, fiber‑cement board, and metal. SIPs are available in thickness from 4‑inch and 6‑inch walls, and thicker roof panels up to 14‑inches, depending on climate conditions. The design capabilities, exceptional strength and energy saving insulation make SIPs a twenty‑first century building material for high performance buildings.

Learn more about Structural Insulated Panels now!