The pandemic has been a surprisingly busy time for concrete restoration and polishing contractors. With buildings such as schools and stores shut down for the quarantine, concrete floor finishing expert Ron Bridges has seen a spike in rentals for concrete flooring equipment at his company, Sunbelt Rentals. “Schools were closed early, so they’re doing a lot more maintenance and stuff now while they’ve got these empty buildings,” he says.

Contractors can expect another boom in refurbishing and resetting stores once the pandemic is over, says Jonn Rippman, vice president of products and product development for Diamatic, manufacturer of concrete grinding and polishing machines.

“When retail does come back, there’s going to be a serious amount of cleaning and resetting the stores with new guidelines and everything, so that’s going to create opportunity in the grinding and polishing markets as well,” Rippman says. “It’ll be an opportunity for all markets, but we believe that more will switch to a polished surface and take the traditional tile out.”

Diamatic’s 31-inch BMG-780 propane planetary grinder and polisher is the ideal machine to prepare surfaces prior to new coatings, such as removing old coatings or adhesive residues; to smoothen or flatten concrete slabs, including curled expansion joints; or to remove unsightly surface imperfections, the manufacturer says.

Concrete floor professionals taking part in this work are increasingly buying or renting equipment powered by propane. While propane has long played an important role in powering large ride-on equipment such as shot blasters and scrapers, manufacturers have introduced new propane grinders and power trowels in recent years that add productivity and convenience to concrete floor jobs without putting indoor air quality at risk.

Propane grinders provide convenience right off the truck

Propane grinders have seen a burst of new products on the market in recent years as they grow in popularity with contractors. Convenience and labor savings are the primary selling points for propane grinders compared with electric alternatives, Bridges says.

“The electrical grinders used for these large jobs, they’re going to run on 240V three-phase or 480V three-phase [power],” Bridges says. “It’s going to be a power source that’s just not commonly available where you’re working, especially if you’re in a big, open warehouse.” Contractors might have to have an on-site electrician hook up the equipment and run cable through the building, or tow their own generator powerful enough to run the equipment.

By comparison, propane grinders are ready to run right off the truck. “You fire it up, and you’re ready to grind,” Bridges says. There’s no cord that could get in the way or create a tripping hazard, and the labor savings can add up quickly. “When we would pull up on a jobsite with an electric grinder, it sometimes took hours to get that thing up to where we could get it to work, if we were relying on site power,” he says.

Another trend driving the move toward propane grinders is the rise of wet grinding in response to OSHA silica requirements, Rippman says. The silica mandates require contractors to have testing protocols and a silica plan, and to outfit workers with N95 masks, all of which can add up for a small contractor. Many contractors have moved to wet polishing, which uses water as a dust suppressant and lubricant for the grinding process, creating wet slurry instead of airborne particulate. Since propane grinders require no electrical cords or hoses, they’re much easier to use in wet scenarios.

Indoor air quality with propane grinders

Lavina propane grinders feature Fuel Minder technology, making them highly responsive to changes in the engine load and providing optimum air-to-fuel ratio and improved fuel range regardless of operating conditions, according to the manufacturer.

Just as contractors turn to wet grinding to improve worker health and safety, they’re also paying closer attention to the indoor air quality of the environments they’re working in. In turn, equipment manufacturers are focusing on reducing emissions to improve worker safety. Manufacturer Superabrasive’s line of Lavina propane grinders is equipped with propane-converted Kawasaki engines, certified by EPA and CARB, and recognized as Blue Sky Series engines due to their lower emissions.

The conversion kits feature Lavina Fuel Minder, a high-performance, digital fuel-control system with closed-loop feedback, fuel lock-off capability, emissions safety warnings with shutdown, and an LCD screen for user interface. “It’s very responsive to changes in the engine load, and it provides optimum air-to-fuel ratio regardless of operating conditions,” says Nikolay Nikolaev, president of Superabrasive. “That allows us to have very high-efficient equipment without compromising the safety of the operators of the equipment.”

When propane equipment is used indoors, proper air ventilation and proper equipment maintenance are critical for operators’ safety, and carbon monoxide levels must be monitored. But the built-in safety features included in propane equipment adds an extra layer of peace of mind for contractors, says Matt McDonald, director of off-road business development for the Propane Education & Research Council. “That’s something that really stands out to me, saying, ‘Hey, this is a great application, safe for your employees, safe for everybody working in there,’” he says.

At Diamatic, the company’s most popular platforms — the 22-inch 555 Pro, 28-inch BMG-735 Ultrapro, and 31-inch BMG-780 Ultrapro grinder polishers — are all available in propane, and any platform the manufacturer develops in the future will be designed in both electric and propane versions, Rippman says.

Powerful and productive power trowels

In addition to a broader variety of propane grinders, contractors will also find new propane options in the power trowel market. Whereas a large propane grinder can cover about 1,000 square feet per hour, a power trowel adds much more power, covering about 10,000 square feet per hour. But because trowels were previously available only in gas and diesel versions, they could only be used in new construction before the walls were up. New propane trowels offer the potential to vastly boost productivity for indoor projects such as large warehouses.

Lavina’s first power trowel, the LP36, features plenty of power for the trowel to work with a variety of tools with the right RPMs during all phases of finishing, from low-speed high-torque to high-speed burnishing while keeping emissions at safe levels, the manufacturer says.

Superabrasive is introducing a line of propane-driven power trowels, which will be available for sale in the fall of 2020. “You’re able to approach projects where in the past you are not able to, especially large big-box stores, where for many years it was cost-prohibitive to put the heavy equipment,” Nikolaev says. “And with that, we believe that polished concrete will only continue to get more popular.”

Diamatic’s Velox power trowel polishing system similarly has been used on several projects measuring over a million square feet each, Rippman says. “That’s been a big part of the market right now in 2020, with COVID,” he says. “Some of the smaller work and smaller projects are being put off, but the larger stuff, as of right now, is still on.”

The growing popularity of propane grinders and power trowels adds to the many ways contractors and facilities pros can utilize low-emission propane in their buildings. In the concrete and flooring space, contractors can use vacuums, burnishers, scrapers, ride-on shot blasters, saws, power buggies, and floor scrubbers powered by propane. But Bridges says customers will frequently utilize multiple divisions at Sunbelt Rentals, getting propane floor equipment from his flooring solutions division as well as propane temporary heaters, propane generators, and propane forklifts and scissor lifts from other divisions.

In turn, propane retailers can make it simple to provide fuel for these large construction projects, delivering a variety of tanks, cages, and bottles to the jobsite so contractors and their subs have easy access to the fuel, says McDonald, who previously worked on similar types of projects as a general manager for propane retailer Ferrellgas in Kansas City, Missouri. “You put them on a rotation where you come and fill them every couple of days,” he says. “You don’t have to bring in a can of gasoline or a can of diesel or get all that out there yourself. The propane retailer will do that for you.”

Top photo courtesy of Sunbelt Rentals.