With a history of water problems, the city of Appleton, Wis., faced a deluge of difficulties. Residential and commercial property owners were very concerned about flooding on their land. Storm water didn’t stop there; it was even impacting local emergency response units and their ability to navigate the city. The city council needed an innovative solution. Midwest Industrial Coatings promised to deliver.

“The council was brainstorming ideas, but nothing seemed foolproof,” recalled Peter Bakke, operations manager at Midwest Industrial. “The necessary structure required an expansive area of land. Eventually, the decision was made to put a below-grade retention basin underground to avoid goose migration and, consequently, mosquitoes on such a large plot of property.”

Location, Location, Location
After kicking around several site alternatives, the local high school was considered. The city decided to install an 88,000-square-foot (8,175.5 m²) storm water retention system under two high school parking lots. The area offered the necessary amount of land and the project could be completed while the school was closed over two consecutive summers. From the last day of school to the last day of summer, the plan was to excavate, install, and backfill the system and then asphalt the parking lots.

While a sound decision, it was not without complications.

“The proposed location for the system was adjacent to a well, so it needed to be below the water table to make sure ground water couldn’t enter and impact drinking water,” Bakke explained. “There were a lot of component pieces, so we had to add joints. The design included storm traps, and the council feared their biggest potential problem would be if they weren’t watertight. We stepped up to plate and said ‘We can make this happen.’”

A woman-owned, Wisconsin-based business, Midwest Industrial started in 2003 and now employs about 10 people. The company works in all 48 continental states; this project was close to home.

First and Down
A three-person crew was assigned to the two-phase Appleton job. Phase 1 took place in spring and summer of 2013 and Phase 2 occurred in 2014. The first step: The crew tested and designed the waterproofing system. 

Phase 1 officially began when 150 precast StormTrap units, which each weighed 28,000 pounds (12,700.6 kg), were delivered from Illinois to Midwest’s Waukesha, Wis., facility. Midwest rented a Manitou forklift with a 45,000-pound (20,411.7 kg) capacity to handle each heavy precast piece.

To accommodate a fast-paced June start time, the crew verified that all the units met the spec and then began the pre-coating process. They used a Graco NXT Xtreme Pump to apply Perlastic by Global Polymer Solutions, a cold-applied liquid asphalt emulsion waterproofing system.

“We unloaded stages in our laydown yard,” Bakke said. “We sprayed all the pieces between April and Memorial Day, and then coordinated delivery by reloading the pieces on semi-flatbed tractor services that we’d contracted to begin installation in the high school parking lot.”

At the site, the crew applied CETCO WATERSTOP-RX 101 to seal the joints. A Bentonite Sheet Membrane Dual Waterproofing System, which is designed for use on backfilled walls, was also used underneath the precast StormTrap units to prevent water from passing through. Finally, an average thickness of 80 mils (2,032.0 microns) each of Perlastic spray grade (SG), roller grade (RG), and trowel grade (TG) were applied over the entire exterior surface. 

“Because of the depth of the units, which were installed 20 feet [6.1 m] below ground, we had to go underground to apply the coating,” explained Bakke. “The other contractors were backfilling and burying right behind us as we were working.”

To ensure crew members’ safety, Midwest set-up a perimeter safety line to demarcate the area. The crew wore harnesses, Tyvek suits, 3M eye and hearing protection, respirators, and high-visibility vests.

Let It Rain
One year later, for Phase 2, the crew repeated the process and pre-coated 180 pieces for the second structure, which would connect to the first to successfully store the storm water runoff.

The second phase was met with more challenges. For starters, this project was twice the size as the first one. Add to that, the summer of 2014 brought excessive amounts of rain — 110 inches (279.4 cm) — and high humidity, which hindered application of the moisture-cured coating. 

Because they used high-pressure spray systems, controlling the product overspray at a large high school with many summer activities presented a problem for any passersby. So, the crew applied coatings in the early morning (from 6 a.m. to 10 a.m.) and late evenings (from 6 p.m. to 10 p.m.) to accommodate setting pieces, traffic on the site, as well as the high temperatures and humidity.

But that’s not all. A great deal of road construction in the area limited access. And because of high water table conditions, the crew had to constantly pump water out of the area.

Teamwork Prevails
Every person on the crew alternated doing different tasks to get the job done in 18 weeks, sometimes working seven days in a row — and nights. The coating was complete on time and ready for backfill. “This is a top-notch team and because of their hard work, the project was a success in the end despite any hurdles we faced,” said Bakke. “Without this coating and waterproofing solution, the project would have never happened.”