Canadian developer sees long-term benefit in hydrodemolition

Drewlo Holdings onsite, using the Aquajet Aqua Cutter 710V hydrodemolition robot to take down a parking structure.

Drewlo Holdings put its trust in an Aquajet hydrodemolition robot when faced with the challenge of a 15-year parking structure project.

With more than 60 years in the property management industry, Drewlo Holdings has a knack for providing the high-quality accommodations Canadian tenants want. In southwestern Ontario, the family-owned company is synonymous with upscale apartment living, boasting more than 9,600 units throughout Burlington, Kitchener, London, Sarnia and Woodstock.

Drewlo employs a full-service approach to property management, which ensures high levels of tenant satisfaction throughout their property portfolio. Investing in the right employees—and the tools to help them reach their full potential—is a key concern when it comes to delivering top-quality facilities. From site preparation and construction to long-term maintenance, Drewlo staffs its crews with engineers, contractors and service staff dedicated to providing the best for their residents.

Faced with a 15-year, multi-phase renovation of its nearly 80 parking structures, management knew investing in the right technology at the start could minimize the labour requirements and financial impact of such a large undertaking. They partnered with Aquajet for an Aqua Cutter 710V Hydrodemolition robot and Rotolance 1000 attachment, hoping to maximize productivity over the duration of the 15-year project.

Quality from start to finish

Investing in proactive maintenance is an important part of Drewlo’s commitment to quality. This not only helps ensure all facilities meet current safety guidelines, but also allows the company to plan ahead when larger repair projects are needed to minimize the impact on tenants and staff. So with a number of its parking structures needing repair, Drewlo tasked the maintenance and special projects department with developing a renovation plan.

“We knew this would be a significant undertaking,” said Allan Drewlo, president of Drewlo Holdings. “We’ve kept up with maintenance at all of our properties, but eventually significant updates are required to meet updated safety guidelines and changing tenant expectations. Our goal was to renovate as many structures as possible while keeping budgets, labour requirements and tenant displacements at a minimum.”

The team identified about 80 structures, the majority of which were one or two-level above-ground parkades. The list also included about 15 underground garages.

Buildup of chloride ions from road salt and decades of wear and tear meant some of the older structures required significant repairs—removal of as much as 60% of the existing concrete in some cases.

“There was a lot of variability from structure to structure,” said Robert Reynolds, special project manager for Drewlo. “Each site presented its own challenges as well as the overall logistical hurdles that come with a project of this magnitude.”

With the resulting schedule, crews would tackle the oldest and most damaged structures first.

Long-term parking solutions

First and foremost, Reynolds and his team had to contend with the hefty price tag that comes with such a large project. Minimizing costs would be critical for overall success. The team identified several areas where costs could balloon quickly—mainly labour and materials.

Tackling the project the traditional way—a large workforce with handheld equipment—went against the company’s policy of innovative, highly specialized crews. Not to mention the long-term financial drain that would result from using this method for the projected 15-year duration of the project.

Using jackhammers also meant crews would have to replace rebar—at a cost of tens of thousands of dollars per structure—since there was no way to avoid damaging it.

Speed seemed to be the next biggest hurdle.

Crews would have to work fast—not just for the sake of the tenants, but because this was only one of several concurrent projects. With an estimated average removal of 15,000 square feet (1,393.5 square meters) on the smaller above-ground structures and 50,000-square feet (4,645.2 square meters) for the larger underground garages, the property manager needed to maximize productivity with minimal labour.

“Drewlo has always seen the value in investing in potential, whether it be people or technology,” Reynolds said. “When we sat down to crunch the numbers, we realized jackhammers and large crews weren’t the answer. We would basically end up rebuilding the structures at a huge cost both in terms of time and money.”

After discussing their situation with Aquajet team members at a tradeshow, Drewlo decided Hydrodemolition provided an innovative solution that would minimize overhead costs and provide a safer, less physical alternative for employees. The impact-free process cleans and descales rebar without damaging it, saving Drewlo an estimated $40,000 per structure. Additionally, the water-based method doesn’t cause microfractures in the remaining concrete, which helps maintain structural stability for longer lasting repairs. The Aquajet equipment would also greatly reduce crew requirements, which would allow Drewlo to work fast while keeping its team small.

Working with Aquajet, Drewlo decided an Aqua Cutter 710V with Rotolance 1000 attachment and Power Pack 700 would provide the necessary productivity to keep the renovation project on schedule. Using the Rotolance 1000 attachment, Drewlo crews can maximize removal in less damaged areas by only taking off a shallow layer of concrete.

The tool covers a surface diameter as wide as 14 inches (360 millimeters) and can provide production rates in excess of 1,500 square feet (139.4 square meters) per hour. For the structures with heavily damaged concrete, the team would need to remove a depth of 3-3.5 inches (7.6-8.9 centimeters). The Aqua Cutter 710V could provide up to 18,700-psi.

Product photo of the Aquajet Aqua Cutter 710V hydrodemolition robot.

Success in the short-term

Working around tenants presented the final challenge to Drewlo’s team. The structures had to remain open for parking. Noise restrictions meant crews could only work between 8 a.m. and 5 p.m. while the majority of tenants were out of the building. Also, vibrations needed to be limited to maintain structural integrity since some structures were connected to the apartment towers and all were multi-level.

Here again, Hydrodemolition presented an ideal solution that exceeded the expectations of both crews and residents in terms of parking disruptions.

“Hydrodemolition isn’t what a lot of tenants were picturing when we informed them of renovations,” Reynolds said. “There was the expected concern for noise, dust and restricted access. However, when we began removal with the Aquajet equipment, tenants were impressed by how quiet it was. We are averaging about 78 dB close to the machine with much lower dB away from the equipment.”

Drewlo Holdings onsite, using the Aquajet Aqua Cutter 710V hydrodemolition robot to take down a parking structure.

Marcel Huard, construction supervisor and site foreman, was Drewlo’s first Aquajet certified operator. He learned on-site as part of the commissioning of the new equipment. Huard is an industry veteran with 20 years of experience in concrete restoration.

A second operator was recently added to the team, as well. Fabio Baldinelli is a 19-year-old construction apprentice just starting his career. Baldinelli displayed an aptitude and interest in the Hydrodemolition method, prompting Drewlo to single him out for training. Both men felt comfortable with the Aqua Cutter after minimal instruction.

“The machine looks intimidating at first,” Reynolds said, “but it has intuitive controls and a user-friendly interface. The hardest part is you have to have a feel for the concrete itself. The robot does what it needs to within the set parameters, but it takes some skill to determine what those are. Marcel and Fabio make a great team. Both of them were able to grasp the functions quickly. With the breadth of this project, we’re lucky to have an experienced manager and young professional involved to ensure quality all the way to the end.”

Drewlo is three years into the project. In that time, Drewlo’s team has been able to streamline the renovation process. The crew stations the Aquajet Power Pack 700 high-pressure pump that supplies water to the robot near a fire hydrant as close to the structure entrance as possible. The robot can be up to 400 feet (121.9 meters) away.

To keep parking open for tenants, Drewlo sets up the renovation in four stages per structure. The crew erects netting and tarps around the active work area to minimize debris movement into active parts of the structure, while wastewater is collected using a sump system that allows it to settle before being passed through four fine filters and eventually released in the storm drain.

During the demolition phase of renovation, Huard or Baldinelli will put 40-45 hours a week on the Aqua Cutter, completing removal in 45 days or less depending on the structure. Reynolds estimates Hydrodemolition saves about 60% of the time compared to using a scarifier or other mechanical means, allowing the team to move on to subsequent tasks, such as pouring new concrete, that much faster.

“Using Hydrodemolition, we’re able to complete renovations in five months to a year, depending on the structure,” Reynolds said. “Any alternative method would have increased the timeline, the labour demands and the budget.”

Investing in innovation

As the renovation project continues, Drewlo hopes to train more operators and increase its fleet of Aquajet equipment. The appeal of high-tech machines and reduced physical labour have proved enticing for young professionals, such as Baldinelli.

“Smart investments lead to long-term success,” Drewlo said. “Hiring the best talent and committing resources to professional development and the cutting-edge tools that will take them even further ensures top-notch service for our tenants for another 60 years.”