Power Trowel Finishing Techniques
A power trowel is an incredibly efficient concrete finishing tool. A good power trowel will flatten out a concrete floor, harden it and give it a smooth finish. There are several styles of power trowels, including walk-behind machines and ones that are sat upon. Whatever style power trowel you use, once you have laid and leveled out a concrete floor, it is the best tool for finishing up the job. This tutorial gives you some basic techniques on how to use a power trowel.
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Selecting a Trowel
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With several varieties of power trowels on the market, each one has positives and negatives according to the site you are working on. Power trowels come with both electric and gas engines and as walk-behinds and ride-ons. The walk-behind trowel, which you push along, generally comes with a 5- to 10-horsepower engine. The ride-on trowels come between 10 to 25 horsepower. Trowels also come in different diameters, with 600mm or less used for refurbishment work in tight walkways, 800-1,200mm for wide areas such as warehouse floors and factories, and 900-1,200mm double heads for large areas that need a good finish and polish.
Floating
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Once the concrete is sufficiently dry, when a worker can stand on the concrete surface and only sink 3mm, it is time to begin the trowel process. The floating pass is the first step in trowel finishing. Using a float blade or a float disc, the trowel is passed from one side of the concrete to the other, with the worker pulling the trowel while walking backwards. The concrete is still soft at this point, so the trowel will clean up the worker's footprints as it moves along. There will be circular marks left in the concrete at this point. These will be cleaned up during the finishing pass.
Finishing
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After the blades have been changed from floating to finishing, it is time to make the final pass. This finishing pass should be performed once the concrete has dried and walking on it no longer leaves indentations. The blades are angled at this point toward the concrete. After each pass, to ensure you get the best finish, a 5- to 10-degree increase in blade angle should be adjusted. The steeper the angle of the blades on the final pass, the harder the finish.
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