c/concrete-finishers

31

joseph_coleman•1d ago

Unpopular opinion: spray-on cure is better than wet curing for flatwork

I know everyone swears by wet curing with burlap and hose water, but I switched to spray-on membrane cure for a 4,000 sq ft warehouse slab in Austin last summer. The humidity was all over the place and we couldn't keep burlap wet consistently. Spray-on gave us a uniform seal that held moisture for 7 full days. No cracking, no dusting, and we finished right on schedule. Has anyone else tried it on a big pour and seen better results than the old method?

25

the_beth•3d ago

Wasted $900 on a bad concrete sealer job

Put down that expensive penetrating sealer from a big box store on a driveway in Phoenix. Looked great for two months. Then it started peeling like sunburn. Had to grind it all off and redo it. Lost a whole weekend and the product cost. Stick with the stuff from your local supply house, not the chain stores.

9

emerychen•3d ago

Serious question, do you fix a bad pour or rip it out?

I was on a job in Portland last month and the finisher got distracted, left a section too wet. We had about 80 square feet of honeycombing and low spots. Do you patch it up with grout and hope it holds, or is that just a temporary bandage on a bigger problem?

15

kelly_hill•4d ago

Spent 6 hours trying to fix a trowel that just needed a new handle

I kept blaming the blade for gouging my finish, turns out a loose handle was throwing my angle off by a hair. Has anyone else wasted a whole day on a tool problem that wasn't even the tool?

25

martin.vera•19d ago

Tried steel trowel vs. Mag float for a big warehouse floor last week

I've always used a magnesium float for my initial passes, thinking it was the standard. But I had a 12,000 square foot warehouse job last Tuesday and ran out of Mag floats. Borrowed a steel trowel from a guy I work with. The finish came out way smoother with less bullshit. Less ghosting and the hard trowel stage was easier. Has anyone else had better luck with steel for big flatwork?

2

patricia_wells•19d ago

Rant: I always thought fly ash was just a cheap filler until I looked at the numbers

Was reading through some old ACI papers last week and found a study that showed mixes with 20-25% fly ash actually had BETTER long term strength after 90 days than straight portland cement. Everyone I work with says fly ash is just the cheap stuff you use when you're trying to save a buck. But the numbers from that 2019 DOT field test in Colorado are pretty clear. Has anyone else seen different results on actual job sites?

12

robin_wright•21d ago

Debate: Hit 10,000 square feet of concrete in one day and I'm split on whether it's impressive or a red flag

Last Tuesday my crew and I poured and finished a 10,000 square foot warehouse floor in suburban Detroit, which was way bigger than our usual 3,000 foot jobs. The pace was crazy fast and we finished on time, but I'm worried the quality took a hit because we rushed the bull float pass on the far corner. Is hitting a massive square footage number a flex that shows you can handle big work, or does it mean you cut corners somewhere to get there?

22

oliver_mitchell•21d ago

6 month old driveway in Nashville finally showed its true color after a good rain

I poured a small residential driveway back in March and the owner was a bit disappointed with how light it looked. Honestly I was too, thought I messed up the mix or the coloring. Well we got a solid rain last week and the whole thing darkened up perfectly, exactly the shade we were going for. The water brings out the integral color way better than any sealer I've tried. Anybody else see a big difference after a rain on their jobs?

2

stone.jesse•23d ago

Watched a slab cure completely different after I switched from wet burlap to curing compound

Did a 4000 sq ft warehouse floor in Denver last spring, used wet burlap on half and a spray-on compound on the other half just to test, and after 28 days the compound side was way harder and had almost no surface dust. Anyone else notice a big difference between curing methods on big pours?

26

charles_coleman•26d ago

Just ran the numbers on a job I did last month and I'm still mad

I was punching up some bids for a driveway in Austin and decided to check my actual costs from a patio pour I did back in September. Turns out I was 14% over on materials because I didn't account for waste on the mix design I used. Found it buried in a spreadsheet my foreman kept, and now I'm kicking myself for not catching it sooner. Anybody else ever realize they've been losing money on a certain mix for months without knowing?

28

jordancoleman•26d ago

Took me 5 hours to fix a low spot I should have caught in 20 minutes

Last week on a garage floor pour in Toledo, I missed a low spot near the control joint by about a quarter inch. By the time I caught it, the concrete was already starting to set and I had to grind it down with a cup wheel. That little mistake turned a half day job into a full day messing with patching compound and dust. Any of you guys have a trick for catching low spots faster before the mix stiffens up?

25

the_oliver•27d ago

Hot take: Too many finishers skip the curing step on flatwork

I was on a job site last week in Denver helping a buddy pour a 40x60 garage slab. The crew finished it smooth, got their lines in, and then just walked off. No wet cure, no curing compound, nothing. Three days later it had hairline cracks all over the north side where the sun hit it hardest. Am I the only one who thinks this is a lazy shortcut that costs everyone down the line? How do you guys handle curing when the weather is dry like that?

4

fiona_sullivan29•27d ago

The one time I didn't bleed my air line before a big slab pour

Had this 30-yard driveway pour in Phoenix last July and my finish looked terrible, all pockmarked. Turned out my compressor had been building up moisture for weeks and I never cracked the drain valve before hooking up my tools. Anyone else learn that kind of basic upkeep lesson the hard way?

21

tessa394•28d ago

Hit my first solo 100 yard driveway pour this Labor Day

Been finishing concrete for about 3 years now, mostly doing small patios and walkways. I graduated last year from a 2 year trade program at a community college near Cleveland. This was the first time my boss let me run a whole driveway solo with just one helper. We did 100 linear feet, about 10 feet wide with a slight curve near the garage. Took us 6 hours from pour to broom finish and I only had to fix one small edge that chipped. Felt pretty good actually, like all that practice finally paid off. Anyone else remember their first big solo job and how it went?

13

martin.vera•1mo ago

Always thought power trowels were overkill for small slabs until I helped a guy finish a 300 sq ft patio in 20 minutes flat

Ngl I was the guy pushing a hand float for years on every job under 500 sq ft, but watching that thing spin out a glass-smooth finish in a quarter of the time made me rethink my whole setup - anyone else switch sides on a tool you swore you'd never use?

18

the_dylan•1mo ago

Learned a trick for broom finish lines on a big driveway job in Ohio last fall

We were doing a 2,400 square foot driveway outside Columbus and the weather was changing fast. The sun was coming out from behind clouds and it was drying the concrete way quicker than we planned. I started my broom lines from the far end and worked backwards toward the street, which saved me from having to walk over already finished sections. Has anyone else had to adjust their order of operations last minute like that?

5

milar46•1mo ago

Saw a guy use a magic trowel at a job site in Denver and it changed my finish game

I was working a sidewalk pour last Tuesday over by the old courthouse and this older finisher pulls out this beat up trowel that looked like it had been through a war. He did his final passes with it and the surface came out glass smooth without any of the chatter marks I usually fight with. I asked him what kind of trowel it was and he just said it's a 36 inch magnesium with the edges worn down from years of use. So I grabbed an old trowel from my truck and spent an hour sanding the edges down with 80 grit paper. Next day I tried it on a garage apron and the finish was way better than anything I ever got with a brand new trowel. Has anyone else ever filed or sanded down their trowel edges to get that smooth float effect?

31

tyler176•1mo ago

Changed my mind about using accelerators in hot weather

For years I swore by calcium chloride accelerators no matter what the thermometer said. Last August we had a 97 degree day on a driveway job outside Austin. I mixed in my usual dose and that concrete went off in like 15 minutes. We were scrambling just trying to get it screeded and the finish turned out rough with a bunch of cold joints. My partner Mike said why not just let the heat do the work next time. So this spring I tried a batch with nothing added on a 90 degree afternoon and it gave me a solid 40 minutes of work time. The finish came out way smoother and I didn't have to panic the whole time. Has anyone else made the switch off accelerators when it gets hot?

16

victorb51•1mo ago

Tried using a power trowel on a small patio slab - big mistake

Last weekend I figured I'd speed things up on a 10x12 patio in my backyard by using my 36-inch power trowel instead of hand finishing. Ended up digging into the mix and throwing mud all over the edges, plus I got a wavy surface that took me an hour to grind flat. Learned the hard way that power trowels are for big open floors, not tight spaces where you need to feel the concrete. Any of you guys use a power trowel on small jobs and regret it too?

22

kim_nelson•1mo ago

Watching my neighbor try to fix his sidewalk slab made me realize something about curing

He poured a patch last Tuesday and started walking on it the next day because it felt hard. I told him to give it at least a week, but he said it was fine. Now it's all dusty and the edges are crumbling because the surface dried way too fast. How do you guys explain proper curing time to homeowners without sounding like you're just stalling?

10

lopez.brooke•1mo ago

I was burning through magnesium floats for years until a guy in Boise set me straight

I was working a big patio pour in Boise last summer and my float was just dragging, leaving marks. This older finisher on the crew saw me struggling and said, 'Kid, you're pressing down like you're trying to bury it.' He showed me how to let the weight of the tool do the work, just guiding it. I'd been using way too much arm force the whole time, which is why my floats wore out so fast. Anyone else have a simple trick that saved them a ton of effort and cash?

20

janac59•1mo ago

Spent $800 on a laser screed attachment and it just gathers dust in my trailer.

Everyone on the crew said it would cut our setup time in half for big pours like the warehouse floor we did in Boise, but the learning curve killed our rhythm and we ended up behind. Has anyone else bought a tool that sounded great but just didn't fit how you actually work?

29

aaron_ellis42•1mo ago

The week we poured that 40-yard basement slab in a January thaw

We had three days of 50-degree weather in Chicago, which let us get the pour done and cured without a single heater or blanket. Anyone else remember a winter job that just went perfectly against the odds?

16

angelac63•1mo ago

Serious question, I was finishing a patio in Spokane and the homeowner pointed out a weird shadow line.

I'd been using a 14-foot magnesium bull float for years, thinking the longer reach was always better. The customer showed me how the afternoon sun caught a slight dip I'd made on the pull back, creating a visible line across the whole slab. What's the best way you've found to check for flatness in different light before the final set?

15

dakota_singh39•1mo ago

Finished a 4000 square foot slab solo for the first time last week

It was for a new warehouse floor in Boise, and the crew was short. I had to handle the pour, bull float, and finish by myself. I was sure I'd see cracks or waves, but the owner called today and said it was the flattest floor he's ever had. Has anyone else had a big solo job turn out better than expected?