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COATINGSPRO JULY 2016 51 Moisture Survey that identifed waterlogged insulation beneath the roof 's membrane system. With the scope of repairs fnally defned, the Brazos crew couldn't wait to start! Jobsite access was great. A fter coordinating parking lot closures w ith school facility management, the men backed their 24 -foot (7.3 m) Ford F- 650 and 26 -foot (7.9 m) International 4900 box trucks right up to the buildings. First, the Brazos crewmen cut out sog g y insulation panels and replaced them w ith 4 -foot-by-8 -foot (1.2 m x 2.4 m) sheets of 2-inch thick (5.1 cm) GAF foam board. T hey topped the repaired sections w ith ½-inch-thick (1.3 cm) DensDeck fiberglass mat board and sealed the newly created joints w ith Tremco SOL ARGAR D poly urethane seam sealer. But sealing didn't stop there. "We used 4- and 6-inch [10.2 cm and 15.2 cm] rollers with ⅜-inch [1.0 cm] nap to spread seam sealer over pre-cut strips of Tremco PERMAFAB polyester fabric, maintaining 4-inch [10.2 cm] overlaps," said Brazos superintendent Victor Reyes. "We did the same on all fashings and on every existing membrane seam to create an additional line of defense against leaking." What's That Smell? Te crew then fred up their Graco 833 airless rig and sprayed a 1-mil (25.4 microns) approximate DFT single pass of Tremco A lphaGuard WB water-borne primer. Unlike the A lphaGuard basecoat and topcoat, the seam sealer and primer were not zero volatile organic compound (VOC). Terefore, the Brazos crew scheduled as much work as possible around classroom hours so students wouldn't be mumbling, "W hat's that smell?" "We're very conscious about environmental stewardship at the Sierra Community College District," said Colin Irwin, deputy director of plant operations. "We always try to look at the full impact of our decisions, so in advance of this project, we actually brought test batches of (still curing) coatings into one of our buildings to see how much odor they let of. Brazos complied with all safety requirements and worked well with the JOB AT A GLANCE PROJECT: Apply bio-based coating system on 10 roofs at a community college in California COATINGS CONTRACTOR: Brazos Urethane Inc. 1031 6th St. N Texas City, TX 77590 (866) 527-2967 www.brazosurethane.com SIZE OF CONTRACTOR: ~150 employees nationwide SIZE OF CREW: 10 crew members PRIME CLIENT: Sierra Community College, Rocklin 5000 Rocklin Rd. Rocklin, CA 95677 (916) 624-3333 www.sierracollege.edu SUBSTRATE: Single-ply, roll-down membrane SUBSTRATE CONDITION: Poor; near end of service life with multiple leaks SIZE: ~134,700 sq. ft. (12,514.0 m²) DURATION: 70 days UNUSUAL FACTORS/CHALLENGES: » The school placed emphasis on environmental issues, such as avoiding landfill use, saving raw materials, minimizing odors and volatile organic compound (VOC) discharge into atmosphere, and saving water. » The buildings were occupied while the crew worked on the roofs. » This was the first commercial spray application of Tremco AlphaGuard urethane system. MATERIALS/PROCESSES: » Had Tremco's WTI RoofTec Roof Cleaning Division hydro-clean the roofs and vacuum the spent materials » Had another Tremco crew complete a Thermacore Roof Moisture Survey to identify waterlogged foam insulation » Replaced waterlogged foam and covered the areas with fiberglass mat roof boards » Installed Tremco PERMAFAB polyester fabric into Tremco SOLARGARD polyurethane seam sealant at repair seams, flashings, and all existing PVC and TPO seams laps » Spray applied a 1-mil (25.4 microns) approximate dry film thickness (DFT) single pass of Tremco AlphaGuard water-borne primer » Spray applied a 32-mil (812.8 microns) approximate DFT single pass of Tremco AlphaGuard bio-based polyurethane basecoat » Spray applied a 32-mil (812.8 microns) approximate DFT single pass of Tremco AlphaGuard bio-based polyurethane topcoat SAFETY CONSIDERATIONS: » Wore organic vapor respirators and fall protection harnesses as required » Used warning line system as required Around the s eam s , fla shing s , and s eam laps , the crew ins talled a polye s ter fabric into the seam sealant. The fabric wa s PERMAFAB and the sealant wa s SOL ARGARD, both from Tremco.