c/concrete-finishers

A civil engineer changed how I look at control joints

Last Thursday I was pouring a slab for a detached garage in Tacoma and the engineer stopped by to check the rebar. He asked why I was cutting joints every 8 feet and I told him that's just how I've always done it. He pulled out his phone and showed me pics of cracked slabs that followed the exact lines I was putting in. Said the saw depth matters more than spacing if the subgrade isn't compacted right, and I had never really thought about it that hard. Has anyone else had a designer or engineer point out something basic that made you feel like you'd been doing it blind for years?

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skyler_jackson27•3d ago

Stamped concrete color hardener went way darker than the sample chip

I laid down a burnt amber color hardener on a patio in Fresno last Friday and it came out almost chocolate brown after the sealer cured. The sample chip showed a light tan finish so I'm wondering if I overworked it with the power trowel or if the humidity messed with the pigment. Anyone else had color hardener shift this much on a warm day and how do you adjust for it next time?

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spencer782•3d ago

Talking to an old school finisher made me question my epoxy prices

Met a guy who's been doing floors since the 80s at a supply yard in Denver and he said I'm charging too much for prep work, but after breaking down my labor and materials to him he admitted he was just stuck in his old rates, so is it fair to charge premium for extra grind time or should we all just eat the cost to stay competitive?

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milarodriguez•3d ago

Old timer's broom trick saved my garage floor today

Finished a 900 sq ft garage slab in Fresno this morning and a guy who's been doing this since the 70s watched me work for a bit. He said I was floating too early while the bleed water was still heavy. Told me to wait until it looked like a wet mirror, not a puddle. I've always rushed that step (impatient, I guess) and fought the surface for an extra pass. Today I waited an extra 20 minutes, used a magnesium float instead of my usual steel, and the finish came out way flatter. Not a single low spot. Has anyone else gotten a random tip from a veteran that made you feel like an idiot for not figuring it out sooner?

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jakejones•5d ago

One inspector in Columbus changed how I do control joints forever

Back in 2017 I was finishing a warehouse slab outside Columbus, about 18,000 square feet. The inspector walked up while I was cutting joints and said, 'You're spacing these too close, they're gonna look like a checkerboard.' I argued the spec sheet said 15 feet max. He pointed at the ambient temp and said, 'That's for summer, not a 40 degree morning.' He was right, the next day we had zero random cracking. I still adjust for season now, take it with a grain of salt, but has anyone else had an inspector teach them something that actually saved a pour?

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wood.faith•6d ago

Washed my forms with diesel for 8 years, turns out it was ruining my cure

I used to spray my plywood forms down with diesel fuel before every pour, thought I was being slick preventing sticking and rust. Last fall a DOT inspector in Spokane pointed at the blotchy spots on a wall I'd just stripped and said the diesel was eating the form release and killing my surface finish. Anyone else spend a decade doing a cleanup shortcut that was actually causing the problem, and what finally tipped you off?

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jennifer833•8d ago

Power trowel vs hand trowel on a 40 degree day in Phoenix

Tbh I ran a crew out in Phoenix last week and we split the slab, half finished by hand and half with the power trowel. The hand trowel side had way better cream and no washout, but it took us 2 extra hours and my knees are still mad. Anyone else think power trowels are only worth it on huge pours, or am I just old school?

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allen.kai•9d ago

Overheard a GC trash talking power trowels on a high rise pour

Standing at the edge of a 14th floor deck last month, I caught the general contractor telling his intern that anyone using a power trowel instead of hand floating is just lazy. That really got under my skin, especially since I've run a 36 inch machine on 5000 psi mixes for years. Hand floating that slab would've taken us 3 extra hours and still wouldn't have matched the density we got. Has anyone else had to bite their tongue when some office guy who's never held a bull float lectures the crew?

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anderson.piper•12d ago

My old finishing trowel finally gave out mid-pour

Been using the same trowel since I started out in Tulsa in 2009, and last Tuesday it snapped right in the middle of a garage slab. Had to grab a spare from the truck and finish the job with a different feel, took me an extra 45 minutes to get the surface right. Anyone else ever have a favorite tool fail at the worst possible time and have to adjust on the fly?

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emerym36•12d ago

Overheard a GC in Denver saying he bids 15% higher on any job we touch

Apparently one bad crew left a slab so honeycombed the engineer made them rip it out, and now he thinks we all do sloppy work, so how do you guys handle contractors who judge every finisher off one bad apple?

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corablack•15d ago

Rant: My power trowel blade locked up mid-pour on a 4,000 square foot garage floor

Happened last Thursday out in Modesto. We were about halfway through a commercial garage slab, mix was right on schedule, everything was flowing smooth. Then the blade assembly on my old MBW just seized up. Sounded like rocks grinding, then nothing but a dead motor hum. I killed it fast, but by the time I got it off and looked at it, the bearings had fried and the blades were dug into the pan. Had to hand-finish the rest of the floor with two guys and a bull float. Cost me the whole afternoon and about $300 in lost time plus parts. What do you guys run for daily trowel maintenance? I greased it every month but I'm wondering if I should've been checking the gearbox oil more often. Anyone else had this happen on a big pour?

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elizabethmason•15d ago

Hit 500,000 square feet last month, never expected to track that

I've been finishing concrete for about 11 years, mostly driveways and patios in the Portland area. Last month I tallied up my job logs out of curiosity and landed on 500,000 square feet total since I started keeping records back in 2015. That number surprised me because it's roughly 9 acres of slab, and I never thought about it as a whole until I added it up. The reason it matters is it helped me see which methods actually hold up over time, like how my 3/8 inch rake technique cut my patch repairs by a third. It also made me realize I should charge more for colored work since I've done 40 percent of that footage in the last two years alone. Anyone else keep a running total of their pours, and did it change how you bid jobs?

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wesleyb20•18d ago

Wetting the sub twice before pour saved my float in Austin heat

I was finishing a 40 foot driveway in July and the mud was setting up before I could even get my bull float on it. A old timer walked over and said to soak the sub base down real good the night before and again an hour before the truck shows up. I tried it on a smaller pad last week, 12 yards, and the bleed water bought me almost 30 extra minutes of working time. Anyone else do this on hot days, or do you just adjust the mix with water reducers instead?

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avery_jackson•18d ago

Question about sealers on stamped patios in humid climates

Last month I finished a stamped patio in Houston and used a water-based sealer like I always do. Two weeks later the homeowner called saying it looked blotchy and hazy in spots. Turns out the humidity was so high the sealer didn't cure right, even though I waited the full 24 hours. Has anyone else had this problem with water-based sealers in the South, or should I switch to solvent-based for summer jobs?

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holly_reed55•21d ago

Appreciation post: the broom finish tip I ignored for 12 years finally clicked at a job in Boise

I always dragged the broom in straight lines until a foreman laughed and said 'you're pushing it backwards, son', and now my driveways in Boise actually drain during rain, so has anyone else realized they were flipping a simple step this whole time?

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the_ruby•21d ago

Warning: pump line blew on a 9th floor pour in Seattle

We were running a 60 meter boom pump on a high rise last month and the line coupling let go mid pour, sprayed slurry all over the rebar and a guy's truck below. The foreman just said "clean it up fast" but the concrete had already started skinning on the rebars, and we had to jackhammer out 4 cubic yards. Have any of you dealt with a sudden line failure mid-pour and how do you pre-check those couplings now?

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tara642•21d ago

Watched a crew pump wet shotcrete inside a tunnel last week in Denver, still prefer dry gunite

I started in the 90s doing dry gunite on swimming pools around San Antonio, always had the nozzle guy calling for more water and we'd fight the dust cloud on every batch. Last week I watched a wet shotcrete crew line a 200-foot storm tunnel section and they had almost zero rebound, just smooth layers going down. But their setup cost a small fortune with the pump truck and the mix delivery schedule, plus they had to wait 45 minutes between loads. Dry mix we could stage bags, tweak the water on the fly, and fix a bad spot in 5 minutes without calling for a truck. Is wet shotcrete really the way forward for everyone, or do you guys still find dry gunite faster for small repairs on existing structures? I know the dust is brutal but the control feels better to me, what do you all think?

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wendy131•23d ago

Edge cracking on a 60 foot driveway pour in Phoenix

Poured a 60 foot driveway last Tuesday and the edges spider-cracked by Friday, all along the forms. I used a 1 inch chamfer strip and wet cured it, but the 110 degree heat still got us. Has anyone had luck with a different edge tool or timing the curl here in the desert?

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spencer782•23d ago

Went from magnesium float to a trowel machine on a big slab, night and day difference

Did a 4,000 square foot warehouse floor outside Fort Worth last Tuesday. I've always been a hand float guy, thought power trowels were for rookies or guys on huge pours only. But my partner kept pushing me to try his old ride-on, and after about 15 minutes I was flying. The finish was way more consistent, and my knees didn't feel like I'd been at a rodeo. Has anyone else switched late in their career and felt dumb for not doing it sooner, or is there a downside I'm missing with trowel machines on smaller jobs?

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jenny47•29d ago

The laser level I mocked in 2019 is now the first tool I grab

Back when my buddy brought a rotary laser to a sidewalk pour near Dayton, I laughed and said my string line was good enough. Then he set grade in about 10 minutes while I spent an hour rechecking my pins, and the slab came out dead flat. I bought a green beam unit for $220 last spring and haven't touched a chalk line for forms since. Anyone else switch over and find their old methods feel slow now?

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robins83•1mo ago

Found a way to keep broom finish lines straight without a string line every time

Been doing driveways around Columbus for about 4 years now. Always fought with the broom finish going crooked, especially on longer pours. Tried using a 2x4 as a guide but it kept moving. Last week I tried clamping a straight edge to my knee boards and running the broom along that. Worked way better than I expected. Lines came out dead straight the whole 30 foot run. Anybody else got a trick for this or am I overthinking it?

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kelly638•1mo ago

Appreciation post: cheap laser level saved my pour on a sloped driveway

Last Thursday I had a 12 yard pour for a driveway in Maplewood and the grade was all sorts of wonky. My old string line setup got knocked over twice and I was ready to just eyeball it. Pulled out a $40 Bosch laser level I grabbed on a whim and shot the corners in under 10 minutes. It was dead accurate to my transit check and the finishers actually trusted the marks. Anyone else rely on a budget tool that outperforms the fancy stuff on a panic day?

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karen361•1mo ago

The garage floor in my uncle's place looked brand new after 22 years

Went back to my hometown in Boise last weekend to help my uncle clean out his shop. That slab he poured back in 2003 had oil stains, tire marks, and this weird dark patch near where he always parked his harley. He told me he got tired of looking at it so he rented a grinder for two days and went over the whole thing with a 30 grit diamond cup. I figured he just sealed it and called it done but he actually put down two coats of a densifier and then polished it up to a 800 grit finish. The difference was unreal, same concrete, same cracks in the corners, but it looked like a showroom floor. I've been doing flatwork for 14 years and never thought about grinding down an old slab instead of just pouring over it. Has anyone else tried giving an old driveway or garage floor a second life this way, or is that more of a headache than it's worth for residential jobs?

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rose_reed•1mo ago

Had a talk with an older finisher about curing blankets that really stuck with me

I was on a job site last week in Portland and this guy in his 60s who used to run a crew back in the day saw me pulling off some plastic sheeting and just shook his head. He said "you kids treat concrete like it's made of steel" and then spent like 20 minutes explaining how much moisture loss actually hurts the top 1/8 inch of a slab even if it looks fine. It hit different because I've always been the guy who rushes to get the finish done and move on to the next pour, you know? He showed me this old cotton blanket he still uses that he soaked down and it kept the concrete damp for almost 3 days straight. Now I'm wondering if I've been putting down enough curing time on my residential driveways this whole time. Has anyone else tried the old school wet blanket method over modern spray on cure compounds?

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evan_green52•1mo ago

Overheard a homeowner talking about my broom finish like it was fine art

Last Tuesday I was finishing a small patio in Arlington, and the homeowner was on the phone with a friend. She said I was "sculpting the surface like a Renaissance painter" which made me laugh so hard I almost messed up a joint. I mean, I was just using a push broom and some elbow grease, not a chisel and marble. Has anyone else had a client or passerby say something totally over the top about your work?

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