Rice is grown in water-filled paddies around the world, and then, at the other end of its life cycle, it is cooked with water before eating. But the step in the middle — when the harvested rice is stored — needs the opposite: to be dry. In fact, water can cause serious issues for harvested and stored rice, which means that when the roof at a facility in Minnesota started leaking, they needed to do something about it ASAP.
This is where the Polar Insulating crew was called in to help. Actually, they called on the potential facility first — about three years earlier. The contracting company’s owner and president Tom Kallio had driven around to nearby small towns, dropping off his card with brochures about spray polyurethane foam (SPF) and coating systems for buildings with metal roofs. “I just went to the buildings that looked like potential projects, and three years later, he called me back,” he explained of the facility manager.
According to Kallio, northern Minnesota is one of the areas in the world where rice grows well in the wild. Not only do the lakes lend themselves toward nurturing this grain, but it’s intrinsic to the local Ojibwe people, too. It is in this area that another group, Europe-based Riviana Foods, has cultivated a business.
The company had an audit of their Minnesota facility on the horizon and a leaky roof to contend with, despite using bags up top to try to control the moisture. They needed a waterproofing solution, and they needed it fast!
Winter Weather in May
The Polar Insulating crew’s work for Riviana actually started with two roofs. They coated the 14,400-square-foot (1,337.8 m2) roof over a rice storage building using Lapolla’s Thermo-Prime topped with Thermo-Flex Acrylic. They also installed a coated SPF system over a 4,800-square-foot (445.9 m2) roof above an electrical room. SPF, also called spray foam, was an option for that roof because of its temperature challenges. There was heat coming up from the electrical components, as well as ice damming happening during winter up above. Additionally, that roof had some existing polyurea portions. “This one here had such potential problems, I asked them if they would consider foam for that small section,” Kallio explained.
Polar Insulating needed to be finished by June 15, which is when the auditors were coming in. The crew had exactly two weeks to complete the work, and with a moisture-intolerant system being set to go on up top, the weather mattered.
Not only did the coatings crew experience snow in late May that year (temperatures hit the 20s Fahrenheit, or about -2 to -6 °C, at night), but they also had some humidity concerns, which could — and did — affect the coatings. Luckily, “we hit a little stretch of good weather just before it,” Kallio said. “So it worked out really well. Otherwise, it was too cold to put acrylics down — too damp and too cold.” That was for the non-SPF roof system, but the SPF roof system included a urethane topcoat, which did end up blistering in a few areas because the humidity was so high on the day that it was applied. The crew was able to reapply it successfully.
Both roofing systems started with the same Lapolla Thermo-Prime Acrylic Roof Primer. That layer used the weather, too, but this time to its advantage — because it was black. “It tends to boil out any moisture, ‘cause we get a lot of dew at night, and it tends to boil the moisture out off the roof and bring up the surface temp,” Kallio explained.
Two Roofs, Two Solutions
The four- to five-person crew worked on the two roofs concurrently. Up top, crew members accessed the heights via JLG and Upright lifts. For safety reasons, these were preferable to ladders. They were also protected via ribbons around the roof’s edge and wore 3M masks, safety glasses, and hats to protect themselves from the unrelenting exposure to the sun.
They started by power washing the larger roof with Honda equipment, removing old tar and other debris, and also using hand scrapers. When that was done, those crew members moved on to the SPF roof to wash it, leaving another few crew members behind to start on detailing work for the larger roof.
Lapolla Thermo Caulk was used on screw heads and seams, followed by two coats of acrylic. The first coat was gray for the same reason as the black primer, while the second was white. The full roof received the primer first, applied to an average of 3 mils (76.2 microns), and then the two acrylic coats were applied using a small Graco sprayer up top to a total average of 30 wet mils (762.0 microns) or 20 dry mils (508.0 microns).
As for the spray foam roof, once the surface was washed and primed, the crew applied a 2.8-pound (1.3 kg) roof foam from Carlisle with a Polyurethane Machinery Corporation (PMC) 40 classic, Next-Gen air compressor/generator combo, and 325 feet (99.1 m) of hose. Then, they installed an average 25 mils (635.0 microns) of Uniflex urethane in two passes at ¾ inches (1.9 cm). The crew sprayed on the urethane topcoat with a Graco GH 833 down below connected via a 310-foot-long (94.5 m) hose.
Coating thicknesses were confirmed with wet film thickness gages, except for the urethane, which was confirmed via a slit test with an optical comparator.
Future Work and Workers
Kallio’s original cold call to the client has since turned into annual visits from Polar Insulating. The contracting company has been back three years in a row now. “It works out great,” Kallio said. “They have a budget so much every year, and they just contract us for the amount of budget that they can afford.”
Kallio is working for the future in other ways, too. On this job and others, he had his daughter and son join in the seasonal work. The owner has a few temporary-turned-fulltime employees who he’s trained right out of high school. “They liked it because they made more money than they’ve ever made in their whole lives,” he explained. And it helps to set up the next generation for success.
As for the coating system: “It was really a super product, and it really held up well,” Kallio said. He returns each year to inspect the roofs that he’s worked on, and these two systems seem to be going strong.
