How To Form and Pour A Large Concrete Slab for a Barn
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- čas přidán 18. 02. 2023
- #EverythingAboutConcrete #MikeDayConcrete
This video is about the most difficult forming and pouring concrete slab we had to do in 2022.
It was a 70 foot by 40 foot six inch thick concrete slab with the edges thickened to 16 inches.
The sub-base was sand, thus making it difficult for our stakes / pins to hold the forms in place.
The taller & thicker edges put a lot of pressure on the forms when the concrete is poured in place.
The forms want to move outwards so we have to install a lot of braces holding the forms straight.
The sand isn't compacted enough, like good gravel would be, to hold the braces so the forms want to bow out.
Using the sand for the sub-base made our jobs forming and pouring this slab more than twice as difficult than it should have been.
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I,ve done tons of slabs like that here in MI by Lake Michigan, with the beach sand it is pretty loose , but we compacted it anyway. Around the perimeter you need to backfill 3/4 of the way up the form with sand and you will not have a problem, it is more work, but it doesn’t move then.
I could see there was a bit more stress than your normal pour, but you guys spotted the problems before they were big, fixed them to the best fo your ability and still made it look easy. No blowouts and stellar results once complete. Amazing job Mike and crew, true professionals!
Admire the coolness of your crew no shouting or drama just laying it down…. Top job ☘️
A true artist....never been disappointed watching one of his videos.
This is the typical conditions for the area we pour, I'm on the longbeach peninsula in the state of Washington which is a mile wide and 22 miles long in essence it is just a big sand bar. Our typical slab has a footing that is 12" wide by 18" deep and in order to keep the forms straight we backfill the forms with the sand and use kickers on the inside to keep forms straight until the mud is poured and the maximum slump we pour is a 5 as the pressure from a more fluid mix makes things move, the 5" slump is the sweet spot. Watching the videos in the past I have been envious of how you guys could use the fluid reducers without any issues. Same with the steel stakes, the only time we can use them is if we are over an old driveway.
Looks like a great finish !!
Haven’t seen one of your videos for a while but I like your intro and the work that you showcase in it is gorgeous!
Welcome back!
@@MikeDayConcrete Thanks Mike!
Calm, cool, collected while delivering a quality product. In other words......professional.
Been there Mike make it arder than it needs to be ,great job getting her done it's what the good ones do
Great work right here. All of em really. Concrete work is hard work. Very gratifying when accomplished. You guys are all masters at what you do. Great videos showing how to get it all done. Very professional. Hats off to everyone, great job, much respect.
On thick edge slabs on grade like this, we cut 3’ or so stakes out of 2x4s, just enough to stake up each end of your forms. Then nail up the 2x12s to your floor height and tack your shorter forms underneath those. It’s easier to run your braces/kickers against a taller, more rigid form like the 2x12 imo. Just how we do it. Nice work though!
spoken like a true PRO. tacking that 2x4 on top is silly and leaves and unsightly seam!
He said they didn't expect such deep sides, so they didn't have their 2x12's with them.
Dang Darin! Showin' us how its done. Good job guys.
Hey Mike, when we run into problems like loose fill we run tie wire threw our forms every couple of feet to hold the braces from bowing out and it works quite well.
Mike, im very impressed how you 4 people can finish this big slab, me in california i will use 8 finishers, Great Work!👏
They don’t finish like we do. In many areas back east they seem to have excessive fines. After a broom finish there is a gritty loose sand.
Great team !!!
Very nice!
Good grief, those forms look touch and go for that volume, you are so calm!
It's a pleasure watching a well-oiled machine like you and your crew.
Way to go Daren!
NICE JOB!!!
Thanks!
Thanks for showing some cleanup, great trick him scrubbing the screed with his boot before spraying.
so glad Tea workin wit u still guaranteed those nerds at the college ain't teaching her work like this for sure
We have a lot of sand issues like that here in Florida. What’s even worse is sugar-sand, which is the same thing only super fine grain.
What we likely would have done there, is - about 3 feet out from the forms, run a continuous 2x4 flat on top of the dirt and steel stake the heck out of it. Then run your kickers back to the top of the 2x4 and nail them off.
Something else we would do is - if you have access, before the slab dirt is trucked in, run a continuous #5 rebar all the way around, about 5 feet inside the slab and wrap perforated steel banding around it, going back out to the outside of the forms. Then bury it with your slab fill. Nail the banding back to the bottom of the forms. The last resort was backfilling the forms but that sucks when you have to dig your forms back out. If you’ve got a machine to dig out, it’s not too bad.
I take pride in knowing all I know, but concrete is not one of those things. I'd like to find a crew in northern Ohio to labor for this summer on my free days and learn all I can. It's definitely an art and something I have to know. Concrete work is no joke, but when it's done by professionals, this is what you get. I enjoyed the video, and I plan on soaking up all the knowledge I can. Great job 👏🏽 👍🏽 great crew and great video. Good luck with everything you do.
Excellent kids!!!
So much talent...........Very impressive !! Not sure how I got here, but you got a thumbs up from me !!
Showed your experience, expertise, and professionalism. Great job 👏 👍
Thanks 👍
I normally dig the bottom off the brace in the ground and on need to used steel pins just berry the end and run a plate compactor over it .some ground I use a jack hammer to drive steel in works very well with less effort.
Luke and Darren are employees that dreams are made of.
This the first vid of yours that I've watched where I see stress in the faces of your people.
The sand for a sub-base made this a stressful pour. Poor choice, should have used gravel. That part of the slab install is out of my hands. It's between the excavator and GC.
Got the camera on his head like victory!
Yes, for sure
You guys won the battle, not surprised! I'm in the process of selling my custom concrete company, it's been one hell of a ride!I'll be 65 in August & have to think about life after concrete, is there such a thing?
That'll be an adjustment for sure. Let me know how it goes.
A few tips Mike: perimeter rebar should be a thicker, placed and pre-tied before the pour.
When the form bows out, never hit the brace with a sledge trying push back in, use the tip of a shovel to pry down against the stake over the brace. this eliminates the risk of slippage and aggravating the situation. I find it incredulous that you stripped and sawcut the same day, but had to go back to drill anchors the next day- just put them in while finishing you had enough people there .
3-4' 2x4 wood stakes with kickers. 2x12 at the top and stack down.
You use the hook to pull up the 6x6 reinforcement wire to save buying concrete dobies. Code calls to support the reinforcement to hold it in the middle to upper third of the slab. Then your guys walk it to the bottom of the slab while placing the concrete. The only place the reinforcement wire is even in the concrete is in the beams, it is resting on the plastic everywhere else.
Good job with the frame I thought I'd see a leak or two from the sand? What a weird choice for a substrate almost makes me think it was an old volleyball court?
It's always a real fire drill when you ain't got a good base for bracing. Great you have a crew that notices that and takes action, letting you know something is wrong. I saw a bow once in a long leg, the guy watchin that side had no idea! Somebody's nephew was "hired" for the summer. He thought that was normal. 🤐
Great job as always. Should have a clause in the contract about NOT using beach sand as a sub base. What a headache I bet..
In Florida where I am a GC, we always engage soil engineers to approve the type of sand for proper compaction; and density testing before spray and pour. Do you guys also follow these principles? Thanks for the vids.
On commercial jobs they test the soil for compaction, not many residential jobs do that here.
Man that kind of pour gives me anxiety! My very first pour ever as a contractor had 16" turned down edges and it was a similar struggle.
Is there an advantage of sawing the joints instead of pushing them in when wet?
the water like consistency you run sure makes screeding look so much easier with that lol is there a standard/ measurement per yard of the plasticizer that you use to get that consistency? What do you tell dispatch when ordering and requesting the water reducer? I'm curious to try that
I’m in a similar weather pattern as you, how do you stop frost heaving on driveways
Should have compacted it and put crushed rock we have done that with job sites like that works alright
That’s a hell of a lot Crete. 70 yards @ $130/per + pump truck = that bill had to be $15k or more for just materials and equipment. Good lawd.
I do about 20 to 30 mono slabs a year. It's what i specialize in. there's plenty you did wrong here but as long as it sold on to the next one.
We did something almost identical last summer. 40x70 full service monopour with 2.5 ft deep edges in sand. 100 plus degree weather, no shade and hot wind. We did it in 2 pours since there's only 2 of us. Sand sucks, had the footer collapsing constantly, and had to run 2 ft kickers out every 2 ft and underpinned with plywood. Fun times.
Rock Hard Concrete & Construc. - In the heat like that Your Only Asking for Big Trouble with only 2 Guys. People like you never learn, why Hurt Yourselves?
@@johnruth4311 Nobody wants to work, people are unreliable and steal stuff, very few have an understanding of the quality of product we must put out, etc. Trust me, I wish I had a bunch of employees. Also, I live in a state with a very high minimum wage so even laborers have to be paid a lot of money.
@@rockhardconcreteandconstru9258 I’m Sorry what your going Through. I didn’t mean to be so hard on you, I didn’t know your situation.I spent 30 years as a Union Cement Mason but had to retire cause I got sick.I wish I could come and help you, is there a OPCMIA Local where your at? I had a Residential Contractor that would call me when he needed guys, maybe a Saturday but we loved making the extra money. Maybe Your local Union Hall could help you out, it’s just a thought but when you need guys you have to do something. I hate you Killing yourselves, especially in 100 degree heat. I feel bad you can’t find good reliable help. You take care my Friend.
@@johnruth4311 Unfortunately union guys around here are expecting to make 40+/hr and they are usually only good at 1 thing. Small custom residential non union workers (the very few of us) have to know how to do everything while keeping a very strict quality control. We have dealt with "20 year experience" union guys that can't do anything right, except for the 1 job they had whilst in the union. The big, rich established companies that can afford to overpay an unskilled finisher really make it hard. Thanks for the kind words, hopefully I can find a couple of guys like you this year.
@@rockhardconcreteandconstru9258 I’ll be Thinking of You Guys, I’ve always Respected You Guys that Have The Guts to Run Your your Business, there ain’t nothing easy about Concrete but What a Great Trade to be in. Hope you pick up Some Good Help this Year, Bless You My Friend
I’m just putting a foundation in so you can put the 2 inch Rigid foam under the foundation wall. Will the weight of the building collapse it. I am an amateur at this, so I am just ask that question.
Do you add setting retarders on a large slab like that to early trucks to even out the set across the whole thing?
Should I’ve poured it a lot stiffer
You needed a 2x4 cross brace with 12' long 2x4s bracing it from the solid ground outside the sand. Yep, more labor. A cross brace 2x4 on edge, you know, is a good brace for this kind of plywood form.
It was mud outside the sand.
What is the tablet on the dash of the truck for?
That would never pass for a slab on grade for us were standard 16” edge with four #4 rebar in footing 2’ on center for floor alway formed with turn buckles to straighten if needed, glad you got it straight lots of mistakes made there.
I think this is one of those occasions when you use a stiffer 4” slump around the edge, and then screed off with 7” topping ?
Yeah looks like also the rain water the night before was just one more thing to make a little more of a wet mix than would have been optimum.
@@tomruth9487 Hi Tom, You Doing Good?
I have about 400 wood stakes pre cut in bins. Ready to rollll
22:28 was the best part.
What's the mix design please?
Can't believe the base met code.
if that sand won't hold the pins or stakes or form....how is it going to support concrete?
Hmm I have a slab prepped for my house with sand though at least it's drained and dry and well compacted. Would backing form boards up with timbers and backfill prevent the problem?
It might help. Sand doesn't hold the pressure well.
Im wondering if you can still use foam under the concrete on a machine shop where you will have heavy machines sitting on the concrete. It seems to me that the weight would mash the foam down flat.
It depends on the foam. EPS300 can support 14psi with a 2% deflection. 14psi doesn't sound like much, but you could drive a loaded pickup truck on it. The truck tyres are pumped to 35-40 psi, but the weight on the foam is spread out over a greater area than the tyre contact area by the concrete and reinforcement. Machines will usually be installed with spreader plates to spread the load. If you need higher loads, Owens Corning Foamglas goes all the way up to 75 psi which (with the right thickness of concrete on top) would have the same bearing strenght the best soil you can find.
Was that sand from a ocean or a fresh water beach?
No spray cure?
Strange seeing the concrete guy laying out anchor bolts. Always good to have framer layout the bolt spacing so as to not interfere with studs and add bolts wherever sill plates join.
Don't like that style of anchor bolt much - very easy to spall the edge when tightened, especially with green concrete. Much prefer epoxy-anchored bolts. A bit more expensive, a bit more labor, but no worries about spalling.
Maybe if you use 2+4 stakes and you wouldn’t had all the pushing problems especially on the end of your kickers.
ended up very tidy ...
I am building a I have a question for should my footings be 12 inches deep and wide no deeper or wider than 12 in please let me know thank you
That kind of depends on what code is in your area, what you're building on the slab, what's under the slab. In general, 12" to 16" edges is good for most residential garages, single story residential buildings as long as there's a good, hard compacted sub-base & a couple rows of rebar in the edge.
I find it interesting the use of rebar versus WWF differs by region. Also the practice of lifting the WWF during placement rather than placing it on dobies. Out of all the slabs I have seen demo'd with the WWF sitting at the bottom of the slab against the subgrade, how is this still an accepted practice? What keeps the fabric off the subgrade as the concrete is screeded? Especially with the almost self leveling mud.
They raise the wiremwsh with the hook and then proceed to walk all over it, what do you think happens to the mesh, it goes back to the bottom. So basically there is no reinforcment
@@johnkunz6004 Good point.
They have stated when you pull up the WWM (wire welded mesh) it does not go down to the bottom, it gets stopped by the rock in the concrete.
I’d put you up against West Coast any day👍
👍🏼🔥
Wow , fundamental issues with the form work. Braces should be close to top and be anchored to a we’ll anchored ledger.
I bought the Milwaukee sds hammer drill and it’s literally the best tool I have invested in so far! Besides my mechanics tools that is my favorite tool.
🤯
Is this why out west they run tension cables thru the concrete?
No that's a clay soil issue.
Why not under hang the form instead of adding the form board to the top
Need to pay you to fly to Seattle and do some work. :)
That could be possible!
@@MikeDayConcrete I'd be afraid to even ask what you'd charge for that.
Why don't
Use board or studs for spiking down in the ground instead of pins if you have this kind of sand to work in.
Just curious: why dont you place anchor bolts before you pour?
It's easier to place them afterwards
@@MikeDayConcrete And more accurate. No chance of them getting bumped or sagging or anything. If the engineer says the hold-down and sheer strength is sufficient, you’re gold.
How is sand going to support the slab? Won’t it sink in spots and break open that slab in a matter of just a few years? I’ve never seen sand use as a base only…
Everything is poured on top of sand in Florida. As long as there aren’t any serious erosion issues and the engineer is happy with the compaction it achieves, it’s fine.
Steel forms don't bow out like wood 🥃😎
Still gotta brace them. Just spaced further apart.
Can you give me a good suggestion for concrete drill bits? The ones I have found are trash.
Bosch or Hilti make good masonary bits. It’s really all about your hammer drill though. If you’re trying to drill concrete without a hammer function on the drill, it’s gonna take forever and you’ll burn through bits butter and likely a couple drills as well.
Hilti all day long
you only get one shot. when the forms start to bow and your profit for the week is heading out the window.
For sand that soft you'd need 2x4 stakes but since you guys would never need them again it would be a huge waste of money.
I realize you didn't do the sand base and were hired to do this job, gotta pay the bills and building practices are different all over but I would have got back in the truck and said Hell No! Fire is hot, water is wet and "You CANNOT pack sand" I don't care what anyone says. I sincerely hope when the slab fails they don't try blaming you.
How long do you have to let the slab sit before you start to walk on it to finish working on it
Depends on the slump, how hot it is outside, etc…. But when you can push your fingers in the concrete 1/4 an inch it is ready. Or when you can walk on the concrete.
@@jackwilliams7738 ok sweet. Thanks
1.5 - 2 hours is about all it needs to be able to walk on it. Unless you’ve got retarder in the mix for some reason.
@@jackwilliams7738 I Think a 1/4 inch is too Wet, 1/8 inch is better, won’t be so Sloppy and You’ll have a Flatter Floor.
On Christ the sold Rock I stand. All other ground is sinking sand.
I guess be thankful your not a concrete contractor in Perth Western Australia.
The entire city of 2 million people with I guess 1 million homes is built on the Swan River Coastal Plain, which is essentially beach sand just like this job.
City’s about 120 miles long and 40 miles wide & every house pad of the million or so + homes is like this pour.
That’s just a normal day at work for grano workers (concrete contractors) here! 🇦🇺😜😂😂😉👍👍👍
Better charge them more
You still bull float behind the screed demon?
I’ve noticed lately people are not bull floating after a power screed, ACI says to always bull float after because it drives the heavy aggregate down and pulls the fines to the surface, makes the surface harder and denser
Why would any one use sand? Suitable compatible fill only.. sands good for utilities but not pads 😂
Hope you charged big bucks for there mistake!
Think you should have used 2x4 steaks with kickers every 3’. Instead of plywood on top a 2x6 would have worked better without bowing out. Why not just wet set J bolts the day you pour? Looks like way too much extra work. 😂
Your basement slabs don't look 4 inches thick, here in Wisconsin minimum is 4"
Beach sand ain’t no good. Field sand is what we use. I’m guess y’all
Don’t have that in your area.
Beach sand is horrible to form in. It sucks packing too and if you laser screed it the screed will ruin the grade. It’s a battle for sure.
Not sure why you didn’t just walk off that job. If it’s not right it’s not right. I don’t think it was worth all your extra efforts and hopefully you got paid for that extra work they created.
Cheapest fill they could find.
Jesus said something about this, building your house on a foundation of sand.
Why wouldn’t you drill your anchor bolts right through plate and then pound them in? I can’t watch you amateurs anymore.
You would have to first drill with a wooden drill bit, then a concrete drill bit. Obviously you're a couch contractor.
Sand is actually really good with footings and slab on grade type deals for compaction but yeah sucks to form haha....I work on an island so I know 😅
Could have back filled edges