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Was finishing a garage slab in Tacoma when the homeowner asked why we trowel in circles

He said his buddy's crew always went in straight lines. I explained the circles help close the surface without leaving lines, which I learned from a guy in Yakima 10 years back. Do you have a set pattern you always use, or does it change with the mix?
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4 Comments
gray_hall4
gray_hall41mo agoMost Upvoted
So is the straight line method just for drywall mud, or does it actually work on concrete too? Sounds like you'd need a perfectly flat trowel and a lot of luck to avoid leaving tracks.
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hollyscott
Hold up, @sean48. Nine times out of ten, circles on drywall is a rookie mistake. But on concrete? It's totally different. The mud is way thicker and you're pressing harder to close the surface, so you don't get those ridges like you would with a knife. I've seen guys try straight lines on a fresh slab and it leaves these little washboard marks that are a nightmare to grind out later. Concrete finishing is basically a whole different animal from drywall mud.
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the_mary
the_mary1mo ago
Wait, doesn't troweling in lines risk leaving marks?
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sean48
sean481mo agoMost Upvoted
Yeah, the "leaving marks" thing is real. Reminds me of helping my dad patch drywall once. He went in circles with the knife and it left these weird ridges that caught the light. Had to sand the whole thing down and start over. Straight lines with even pressure is the only way it comes out smooth.
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