David Miller, owner of Alpine Roofing LLC, Durham, N.C., has been in business since 2008. He specializes in what he calls the “complete roofing package”—making sure that all the areas of a roof are properly installed so the roof system lasts for 30 years or more without any problems. Miller and his crew’s attention to detail has made him the chosen roofing contractor of Durham-based BuildSense Inc., a residential design and construction firm that has a sustainability emphasis.
Miller knew he was doing good work for BuildSense, but he was assured of this fact when BuildSense’s owners—Randall Lanou, LEED AP, MCGP, and Erik Van Mehlman, AIA, CGP—asked him to reroof the existing building that would become the firm’s new office. Not only did they trust Miller enough to reroof their practice’s new home, but they also entrusted him with a roof cover he had never installed before.
“They knew I hadn’t worked with this insulated metal panel product before,” Miller recalls. “But they said I had always done them right and they wanted to give me the opportunity to look at this type of project. It seemed like it was up our alley. We handle things we haven’t done before with attention to detail and an understanding of how water causes problems. We try to do the best job we can.”
BuildSense’s new office at 502 Rigsbee in Durham was built in 1945 as a farm-equipment-maintenance building. The structure had spent its last 30 years as various automotive service centers. The 1-story, 6,000-square-foot solid masonry building had optimal orientation to achieve Lanou and Mehlman’s daylighting and solarpower goals. By adding a second story in which BuildSense and tenants (occupied today by a marketing firm and a yoga studio) could operate, Clear-Vue Glass, BuildSense’s partner in the building’s purchase, could maintain an office, fabrication facility and showroom at pedestrian level.
To create the most energy-efficient building possible, Lanou and Mehlman opted to take the existing structure down to its skeleton, leaving only the masonry shell and primary steel columns and girders. Originally, they planned to maintain the existing roof and build the second story on top. However, the roof sloped from north to south about 3 inches for drainage. The partners decided to remove the wood framing, add more steel and a metal deck, and pour a new level composite concrete slab for the second story.
BuildSense pursued a tight, well-insulated building envelope. For the roof, Lanou and Mehlman specified an insulated metal panel featuring a 6-inch urethane core that boasts an R-value of 42. “It’s also painted white, which significantly helps us reduce our cooling loads in the summer—the predominant loads in a commercial building in our climate,” Lanou explains. “It’s very well air-sealed, very well insulated and it’s reflective.” In addition, the roof cover, insulation and finished ceiling are provided in one component.
A crane was required to lift all panels to the roof from one side of the building because power lines impeded the other sides. “The crane would grab the bundle of panels, which were staged on the high side of the building, and lift them up and over the building to place them on the low side,” Miller says. “It would’ve been so much easier if we had access completely around the building but we had to have a big crane come out there and do that lift.”
Once the panels were on the building near where they would be installed, manlifts further assisted with situating the panels on the roof. “The larger panel sections were 400 pounds each and 42-inches wide,” Miller explains. “They were awkward to handle. You also had to make sure when you were moving them around on top of the steel trusses that you didn’t scratch the finished paint on the underside of the panels, which would serve as the second-floor ceiling.”
Miller says safety was the biggest challenge on the project. His crew was tied to steel beams or apparatus that bolts onto the standing seam once they were past the leading edge. “We also made sure no one got hurt while we were moving the 400-pound panels. You don’t want a 400-pound panel on one man and he’s trying to hold the thing up without his knowledge. Honestly, a 400-pound panel once it is in motion may end up being 2,000 pounds of live load so we had to work in unison. We had one crew leader who would call out the play, saying ‘1, 2, 3, we’re going down’ or ‘1, 2, 3, we’re moving the panel over’.”
The coordination among the crew helped because the panels weren’t packaged exactly as they would be installed on the roof. “Some of them were upside down and we had to rotate,” Miller notes. “Without a lift there fulltime, it would’ve been even more challenging. Plus, we were working about 35 feet above the ground and 15 feet above the concrete floor of the building. We had to stay safe, stay tied off.”
Once the lifting and maneuvering were handled, Miller says the installation, which took about a week, was similar to any standing-seam roof, except each panel is 8-inches tall. “The top of the lock must be engaged while the panel is rotated so the tongue at the bottom of the panel engages with the lock,” he says. “Once you are engaged at the top and bottom, then you manually seam the locks together at the top. When you’re all finished you take a massive power seamer and run down the seam and it locks that joint together, so you have all kinds of wind-uplift value.”
BuildSense’s next goal after creating a tight building envelope was offsetting its energy use with renewables, including wind and solar. Miller’s crew flashed in the two residential wind turbines. Although the turbines ultimately failed, the roof also hosts a 32.6-kilowatt solar array consisting of 136 panels, which has exceeded BuildSense’s energy-production goals. Lanou and Mehlman’s pre-construction energy modeling predicted the clean-energy generation would offset 50 percent of the building’s energy use. After one year of data, the array alone is generating 61 percent of the building’s energy needs.
Miller and his team recently have been hired to flash more renewable-energy systems. “I think, thankfully, some of the installers that are responsible for the entire system are much more cognizant of causing roof problems,” he says. “In this
project, we had to cut the hole and bring the steel up, so the wind installers could mount the turbines. We had to work hand-in-hand to ensure those holes were put in non-structural places. The roofer’s part may be a small part of a renewable-energy installation but it’s a critical part.”
On the Leading Edge
BuildSense’s website contains a list of the firm’s achievements. Among its many awards are several firsts, including the first certified sustainable house built in North Carolina, the first rainwater used for toilet flushing, the first plumbing manifold system installed in a residence, etc. “We like actually working with the inspectors because a lot of times they’ve never seen
something and get excited about it, too,” Mehlman says.
Therefore, it’s not surprising that the duo opted to install an insulated metal panel roof system that is more commonly found on cold-storage and food-processing buildings. No matter how unique the product, Lanou and Mehlman knew it would only be as good as its installer, and, just as they anticipated, Miller and his crew constructed the building’s new roof without any issues.
Miller enjoyed the challenge. “It can be difficult to go outside of your comfort zone and handle something like this,” he says.
“But it is also equally rewarding to work for a builder who trusts you to do all of their houses and have them also trust you to do their office.”
Metal roofing: CF42R insulated metal panels from Metl-Span
The 24-gauge panels are Polar White to reflect sunlight, reducing cooling loads in the summer. The 26-gauge Snow White inside panels serve as a reflective ceiling above the open web steel joists, improving the energy efficiency of electric lighting.
Solar panels: Sharp NU-U240F1
Snowguards: 5- by 5-inch Clear Diamond Texture Sno Gem
Tubular skylights: Solatube International Inc.