Dynamic Duo

EPS & Polyiso Team Up on Concrete Tilt-Up Warehouse Roof in Sandy, Utah

by Kevin Keith, regional sales director, Insulfoam


Two are often better than one. For example, it would be a big job for a single roofing contractor to tackle a commercial roof on their own. However, adding another crew member combines two individual efforts for greater impact, cutting the workload in half and accelerating the entire process.

The power of two further occurs in hybrid roofing solutions. On its own, polyisocyanurate (polyiso) rigid foam insulation is frequently specified as a continuous insulation for roofs. However, polyiso’s high R-values can be delivered at the best cost when used atop a foundation of expanded polystyrene (EPS) rigid foam insulation. This two-in-one roofing approach, known as a hybrid system, can lead to substantial savings on one of the most expensive components of any building. In Sandy, Utah, local roofing contractor Capitol Roofing Service looked to this hybrid solution for the best price and longest warranted R-value for a concrete tilt-up warehouse roof.

Photos courtesy of Insulfoam.

Situated about 1/2 hour south of Salt Lake City, the town of Sandy is booming. The capital’s economic and population growth has spread out to the surrounding metropolitan area, and as a result, more people are moving to and conducting business in Sandy. Utah’s sixth-largest city also draws many soccer fans to its Rio Tinto Stadium, home to Real Salt Lake and Utah Royals FC teams.

Knowing that an up-and-coming city always requires more warehouse space, Synergy Development seized the opportunity to develop land directly across the freeway from the world-class stadium. The Synergy Business Park will consist of six buildings, two of which are complete, on a 24-acre parcel. The developer went with a tilt-up featuring architectural exposed concrete to offer a unique look, while saving the most time and money on the jobsite.

Similarly tasked with finding the most cost-effective approach to the roof, Capitol Roofing Service incorporated one layer of 5.13” EPS insulation from Insulfoam® that was then topped by one layer of 1-1/2” polyiso insulation. “Not only is it good roofing practice to have at least two staggered layers of insulation to prevent thermal bridging, but the EPS insulation foundation also helped address the roofing contractor’s biggest problem, which was the budget,” explained Daniel S. Barker, owner of Division 7 Specialties, Ogden, Utah, the local Versico Roofing Systems representative.

“EPS costs half of what was bid in other insulation options. Even with added fastener costs, the owner still saved double digits per square foot by going with the EPS/polyiso hybrid system,” said Jason Wood, territory sales manager for Insulfoam.

James Fiscus, estimator for Capitol Roofing Service, further confirmed the deep savings EPS afforded. “Cost was one of the biggest reasons we went with EPS insulation,” he said. “The owner gives you a budget, and you figure out a way to stay in budget so you can do the job. Whenever you can save on insulation and get the same R-value, that’s a huge benefit. EPS also led to labor savings, as the insulation is easy to use and easy to cut.”

This enabled construction crews to focus on other, more time-consuming tasks for optimum job site efficiency. EPS’ lightweight properties are largely to credit, requiring fewer workers to lift and position the insulation with ease. Customizable thickness also comes into play, as EPS can be up to 40” thick in one layer. By having one EPS layer that is 5.13” thick, the hybrid roof system requires fewer total layers of insulation, which translates to less adhesive and less time spent installing rigid foam boards on the roof.

While the EPS/polyiso hybrid solution simplified the jobsite and accelerated installation, creating wider profit margins at Synergy Business Park, the dynamic duo was also crucially compatible with a thermoplastic polyolefin (TPO) single-ply roofing membrane by Versico. “The end-user wants products and systems that work well together and can be more efficient,” Barker summed up.

Manufactured by Insulfoam’s sister company Versico, 60-mil of VersiWeld® was rolled out over the polyiso layer. Versico also utilized CAV-GRIP 3V’s Low-VOC spray adhesive, which comes in a pressured canister that dispenses more quickly than traditional roll-on adhesives and leads to additional time savings.

Importantly, the company was able to warranty the total roof system, from TPO down to EPS. “The owner and architect were looking for a 20-year warranty, and that’s something we’re able to provide with the hybrid system involving different divisions of Carlisle® Construction Materials,” Barker said.

Topped by a full system warranty, future Synergy Business Park owners can be confident that the EPS, polyiso, and TPO membrane will stand the test of time right alongside the exposed concrete walls and finishes. “With polyiso/EPS’ long-term, high R-values, R-30 today should be an R-30 in 25 years,” Fiscus said, covering Sandy’s burgeoning business community for the long term.