A school for future engineers should reflect how their talents improve quality of life. That’s one reason the Northern Alberta Institute of Technology chose radiant heat for its Centre for Applied Technology. Instead of a forced-air system that wastes much of the energy required to heat the building’s cavernous atrium, the floor is laced with pipes that warm the first few yards above the surface.
Choices like this helped earn the building U.S. Green Building Council Leadership in Energy and Environmental Design (LEED) Silver certification. So did specifying polished concrete for the highest-traffic first floor. Desco Coatings of Alberta Ltd. polished the 4-inch unbonded overlay to a large-aggregate, high-gloss exposure.
That overlay is directly above an underground parking garage kept at about 50 degrees F. Envision the floor as a sandwich: a layer of R-15 insulation imbedded with heating tubes between a structural concrete slab below and the 4-inch overlay above. During winter, the heating layer operates at 72 to 75 degrees F. Because of the 20-degree temperature fluctuation, the architect specified more joint work than usual for a 37,500-square-foot slab: 6,100 feet of 12-millimeter control joints to address natural cracking and 1,100 feet of full-depth expansion joints to allow for shrinkage.
To see how these elements would all come together, the general contractor and concrete placement contractor installed three cast-in-place mockups. Desco used one early in the construction phase to give the client three grind depths and three sheen levels to choose from and another to test Ameripolish Inc.’s SureLock black dye, which was used to create 2-foot-wide stripes that complement the building’s concrete support columns. Two mockups were destroyed; the dye-test mockup was left in place and covered with tile.
“We were working in the main area, so the amount of other-trades traffic made for a very busy worksite,” says President Daryl Samycia. “The general contractor did a great job of controlling the area, though. There was also a huge amount of inconsistencies in the cafeteria, so we spent much more time there than we expected."