Stubbe’s Precast warms to lean sandwich panel insulation

After years of promoting it in European construction markets, Ireland’s Kingspan Group brought the Kooltherm K20 Concrete Sandwich Board for tilt-up and precast walls to North America in 2017, citing its potential to provide higher performance in thinner cross sections than prior insulating materials. The product is available in a standard size, approximately 48 x 90 in., or custom lengths, and thicknesses of about 2 to 4 inches, netting up to 35 R-value.

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Stubbe’s Precast Commercial enlisted IBI Group of Waterloo, Ontario, to design a total precast structure for a new headquarters. The project required 840 architectural and structural pieces, fabricated at the producer’s nearby Harley plant. PHOTOS: Stubbe’s Precast Commercial
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Kingspan underscores Kooltherm K20’s potential to attain higher thermal performance in thinner profiles than conventional insulation boards: R-value up to R17 in 2-in. thickness. The product has a glass tissue based facing, adhesively bonded to a core of rigid thermoset, fiber-free phenolic insulant. Nearly 23,000 square feet of K20 was used in sandwich panel and other conditions for the Stubbe’s Precast Commercial headquarters. The producer’s production facility and new headquarters are located in Harley, Ontario.

“The Kooltherm product line up has variations for many construction segments—precast, walls, roofs, floors—and there are configurations to handle different applications,” says Tom Macro, a Detroit-based independent sales representative for Kingspan Insulation.

The product’s high R-value, environmental features, plus fire and smoke performance caught the attention of Harley, Ontario-based Stubbe’s Precast Commercial. As design proceeded for a new headquarters office, including sandwich panel specs, the structural and architectural concrete producer targeted a 4-in. insulation board with elevated R-value. Kooltherm K20 exhibited the thermal performance Stubbe’s management envisioned for the envelope of a three-story, total precast structure housing up to 120 employees. Acting as its own engineer of record and precast engineer, the producer incorporated exterior insulated panels, precast interior walls and beams, hollow-core plank, plus double-tee members. The headquarters facility has two wings, plus a center atrium with companion, glass-encased boardroom.

“We have multiple precast finishes on the interior with an integral white concrete exterior accented with various stained portions, as well as thin brick,” observes Stubbe’s Project Manager Albert Meyer. “There are several stained concrete feature walls on the interior, a waterfall in the reception area, concrete countertops throughout the building and a polished-concrete boardroom table.”

The exterior walls required robust insulation, he adds, noting, “Kooltherm K20 really worked well for us, primarily because it provides an R-value of R34 in a reduced thickness. Most insulation boards provide an R-value of R5 per inch. Kooltherm K20 provides an additional R-value of 8.5 per inch. Better insulation lowers heating costs and overhead for the life of the building.”

The board is unique in the market because of its thermal performance, Macro explains, and equips precasters to pursue lean alternatives to thick wall sections, which increase costs and complicate structural connections. “Kooltherm K20 has a fiber-free core,” he says. “Its fire performance is a huge feature and was really important to Stubbe’s. Kooltherm K20 also has a closed-cell structure, so it keeps out moisture and water, is resistant to fungi and is very stable. All of this is important to precasters because it doesn’t reduce the R-value over time. Kooltherm K20 has a low pollution potential and hits all the environmental hot points, which architects really like.”Kingspan Insulation LLC, Atlanta, 800/241-4402;;