CoatingsPro Magazine - January 2022
Leaky Rooftop Fix
Jennifer Frakes 2021-12-28 22:08:46
Downtown Denver Rooftop Receives a Mile-High Makeover
When building owners are confronted with an aging, leaking EPDM (ethylene propylene diene monomer) rubber roof, the last thing they want to hear is that a total roof tear-off is needed. Fortunately, in most cases, coatings contractors can come to the rescue with systems that can be applied over properly repaired and prepared roof membrane.
The rooftops of the two Commons Park West apartment buildings located in downtown Denver, Colo., were no exception. “Greystar, the owner of the Commons Park West property, contacted us about water intrusion issues in and around the air conditioning/mechanical pits and low, That slope areas,” said Ryan Lewakowski, VP of sales at Executive Coatings and Contracting (ECC). “They asked us to put together a bid to either tear off and reroof the areas or come up with another option. After we surveyed the roof areas, we knew that installing a coating system was the right answer.”
According to Lewakowski, it wasn’t difficult to convince Greystar that the application of Uniflex Silicone44 Rubberized Silicone White Roof Coating (provided by Sherwin-Williams) would solve their leaky roof challenges. “We’ve done work with this client previously, and they trusted us to provide the best solution possible. Roof coatings are a much better option for so many reasons, including cost, impact on the environment, and convenience to the residents of the building,” he stated.
Mitigating Disruptions
The Commons Park West apartments are two four-story buildings located in a trendy downtown Denver neighborhood. The buildings have skyline views and are close to many of Denver’s most popular restaurants and attractions. According to Lewakowski, it was crucial that the ECC crew create as little disruption to the Commons Park West residents as possible. “The buildings were completely occupied while we were working on the roof. Although we were going to make as little impact as possible, we still were going to be taking up parking spaces, walking on the roof, and storing materials on the property,” he said.
The crew gave upper floor residents a heads up about workers walking on the roof and any noise that might occur during the job. Most importantly, the crew was extremely careful not to disrupt the air conditioning (AC) service to the residents. “The job took place during the summer months, so keeping the air conditioning units up and running while working on the mechanical pits on the roof was critical to keeping the residents — and the client — happy during the coating application process,” Lewakowski said.
Getting Started
When the crew arrived on the jobsite, the first order of business was to conduct a roof survey and determine the condition of the 16 AC pits and all other flat areas where water might pond. As stated by Lewakowski, the EPDM was showing its age and was in fair to poor condition. “There was separation in the seams and gaps, and many punctures and penetrations had little to no sealant. There were many areas for water to leak,” he explained. Ponding water is especially problematic in a climate like Denver’s, where snow melt leaves a great deal of water on roofs each spring.
Fortunately, the crew found that extensive repairs to the mechanical pits and low areas were not necessary. To aid in the roof survey, the ECC team used thermal imaging technology that shows where active water is trapped. “The FLIR ONE Pro LT is an infrared survey system that attaches to your cell phone and provides you with thermal imaging information through an app. It gives you a quick snapshot of any temperature differences on the roof. In the morning, any water trapped in the roof system will be cooler than the surrounding areas, and at night, the roof system will cool before any trapped water,” explained Lewakowski.
Thermal imaging technology provides contractors with a non-destructive testing method that can quickly target any problem areas. “The biggest no-no in coating roofs is that you don’t coat over water that is trapped in the existing roof system. Identifying areas where moisture intrusion is a problem is critical to the success of the coating system,” Lewakowski explained.
With the thermal imaging complete, the team was now ready to prepare the black EPDM rooftop for the silicone coating application. No mechanical surface preparation was needed; however, large debris was removed from the roof, and all pine needles were cleared out from the AC pits and low areas. The roof was then power washed with plain water using ECC’s custom-built, pull-behind power washer rig.
“After the roof was completely cleaned, we applied Bond-It Wash Primer to all the AC pits and low areas. This etching primer gives the existing membrane more ‘bite’ before the coating system is applied. It really helps with adhesion and bonding by breaking the chemical bond of the inorganic surface of the rubber membrane,” said Lewakowski.
The crew applied Bond-It, which is from another business unit of Sherwin-Williams called KST Roofing Solutions, using backpack pump sprayers. Once the team saturated the areas with the clear, low viscosity, water-based wash, they let it sit on the EPDM for approximately 10–15 minutes. “Then, we rinsed off the roof using the power washer and plain water,” said Lewakowski.
At this point, sealing all seams and penetrations became the priority for the team. One Flash, made by Uniflex, is a gray, one-component, flashing-grade roof sealant designed for single-step application. “One Flash is a one-stop shop. You typically have to embed fabric into sealant to achieve the proper result, but not with One Flash. We applied it to all seams, penetrations, and punctures without needing fabric reinforcement. This saved a lot of labor, time, and money,” said Lewakowski.
One Flash comes in 2-gallon (7.6 L) buckets and sausage tubes. The team used a combination of both caulking guns and 4-inch (10.2 cm) rollers to apply an average of 60 mils (1,524.0 microns) wet film thickness (WFT) to the AC pits and flat areas of the roof. Once the One Flash had cured for 24 hours, the roof was ready to receive the installation of the Silicone44 coating system.
Silicone Solution
Uniflex Silicone44 is a white, rubberized premium silicone roof coating that is ideal for ponding water. “We applied the Silicone S44 using a Graco 933ES Hi-Flo sprayer. Spraying silicone requires special, heavy-duty equipment, like the Graco 933ES. We received training on the sprayer from a Graco rep and received training and support from the coating manufacturer to ensure that we achieved the proper thickness of 30 mils [762.0 microns],” said Lewakowski. Because of the special formulation of the coating, only one pass was needed to achieve that average dry film thickness (DFT).
In addition to protecting the roof from water intrusion, the white color of the Silicone44 offered the mechanical pits and low areas a reflective surface, which was a huge improvement from the black EPDM. “The reflective white roof cuts down on energy consumption, which is a win for the building and its residents, and it’s also great for the environment,” stated Lewakowski.
During the spray-application process, the crew wore long pants, long sleeves, gloves, boots, safety glasses, and 3M half-face respirators. Lewakowski is quick to point out that due to the design of the rooftop, fall protection was not required for any portion of the job.
Special Conditions
With approximately 50,000 square feet (4,645.2 m2) of roof area spanning two buildings, Lewakowski and his crew had their fair share of logistical challenges. “There were 16 mechanical pits and several other low/flat areas between the two buildings. Our crew averaged four to five guys, and we would tackle a couple of pits per day. Once we completely finished those two pits, we’d move on to the next set,” said Lewakowski. The job was further divided into two phases, so all work on the roof of one building was fully finished before they moved on the next.
The crew also had to navigate around all of the mechanical lines within each AC pit. There were 24 air conditioning units in each pit with electrical lines running from each one of them. “We had to be extremely cautious while maneuvering and manipulating the lines so that we didn’t disrupt service to the residents or damage the lines themselves. It was definitely a challenge,” stated Lewakowski.
But it was something else that caused the ECC crew’s biggest challenge over the two-week duration of the job: working in the intense summer heat. Some afternoons, the temperature would soar to 98 °F (36.7 °C), and the extreme temperature was exacerbated by working on a four-story building at a high altitude. “We took lots of breaks and made sure all crew members were hydrated. All team members wore long sleeves and long pants to protect themselves from the intense rays of the sun,” said Lewakowski.
The crew also shielded the spray hoses so that the silicone coating didn’t dry out in the extreme conditions. The coating material itself was stored in a shaded mobile mini-storage container that the ECC team dropped off onsite and was not affected by the heat. And although Mother Nature did heat things up, she did cooperate in another way: The team did not have to contend with any afternoon thunderstorms. According to Lewakowski, this was a big win for the crew because afternoon rain is par for the course during Rocky Mountain summers.
Mile-High Success
Ultimately, the Commons Park West roof recoating job has been a resounding success. The crew set an appropriate timeline with the client, balancing between production and efficiency. “We didn’t want to have too many crew members there at once and be too aggressive with the schedule. It was a delicate balance between being unobtrusive and keeping the residents happy, and keeping the client happy by sticking to the schedule,” revealed Lewakowski. He also pointed out that it helps that Executive Coatings and Contracting has more than 26 years of experience and is set up to handle large-scale jobs in occupied residential buildings.
Looking at the job as a whole, it is clear that the ECC team solved the client’s water intrusion issues by applying a reflective coating system that should stand the test of time and the elements. “I’m happy to say that since the completion of the job, there have been many rainstorms, and there have been no leaks at Commons Park West. We came in and solved the problem we were hired to fix. It really doesn’t get much better than that,” Lewakowski said proudly.
JOB AT A GLANCE
PROJECT:
Apply coating system to AC pits and low areas on two leaky rooftops in two phases
COATINGS CONTRACTOR:
Executive Coatings and Contracting Centennial, CO
LI: ecc-executive-coatings-and-contracting-www.executivecoatings.com
SIZE OF CONTRACTOR:
~30 people
SIZE OF CREW:
4–5 crew members
PRIME CLIENT:
Greystar
Greenwood Village, CO
SUBSTRATE:
EPDM
CONDITION OF SUBSTRATE:
Fair to poor
SIZE OF JOB:
~50,000 sq. ft.
DURATION:
2 weeks
UNUSUAL FACTORS/CHALLENGES:
» Buildings were completely occupied throughout the entirety of the project, so the crew had to communicate work and navigate around the AC units needed to remain completely operational with no service disruption.
» Crew had to maneuver around electrical lines in each mechanical pit.
» Extreme heat and high altitude, made for harsh working conditions for the crew and created potentially drying conditions for the materials.
MATERIALS/PROCESSES:
» Removed debris and power washed the roof using plain water and a custom-built rig
» Applied Bond-It Wash Primer to AC pits and low areas for 10–15 minutes, then power washed the area again
» Applied One Flash sealant to all seams, penetrations, and punctures in the AC pits and flat areas using caulking guns and 4-inch rollers to apply an average of 60 mils WFT
» Applied Uniflex Silicone44 at an average of 30 mils DFT using a Graco 933ES Hi-Flo sprayer
SAFETY CONSIDERATIONS:
» Wore boots, eye protection, and 3M half-face respirators to spray
» Deemed fall protection unnecessary due to the rooftop’s design
» Stayed hydrated and wore long pants and sleeves to protect against the heat and sun
VENDOR TEAM
3M
Safety equipment manufacturer
St. Paul, MN
FLIR Systems
Equipment manufacturer
Wilsonville, OR
Graco Inc.
Equipment manufacturer
Minneapolis, MN
The Sherwin-Williams Company
Coatings and materials manufacturer
Cleveland, OH
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