# acceptable concrete overage



## jmacd (Jul 14, 2009)

We do the prep work, the GC pays for the concrete and hires a slab contractor.

On one project last month we were 2% over on a 150 yard pour, pretty good I thought. 

We prepped for a 90 yard pour yesterday and they poured the slab today. Two more to go same size to complete. We were 4.5% over according to the GC's numbers. The prep work was gravel not crusher run or stone so my grading box had a harder time with the larger stones. We spent a lot of time checking grades.

The GC complained of course so just wondering what is a industry standard. Looked in spec book and it is not specified. 

I don't think it will rise to back charges or anything like that. Just wondering what you guys think is reasonable.


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## Dan_Watson (Mar 1, 2008)

Who calculates the amount of concrete ordered?


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## cdkyle (Jul 12, 2009)

Sounds pretty good to me. Do you ever have a call back or come up short?


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## griz (Nov 26, 2009)

Sounds like pretty tight numbers to me.

I'd be more concerned & thankful that nothing blew out and the slab met tolerance.

Sounds like the GC has his panties in a bunch because he was low bidder.


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## jmacd (Jul 14, 2009)

Dan_Watson said:


> Who calculates the amount of concrete ordered?


GC calculates. I did my own by square footage and came up with 89 yards then add a 5% waste so 93.45 they said they used 95 and should 90.


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## jmacd (Jul 14, 2009)

griz said:


> Sounds like pretty tight numbers to me.
> 
> I'd be more concerned & thankful that nothing blew out and the slab met tolerance.
> 
> Sounds like the GC has his panties in a bunch because he was low bidder.


The slab was 5" slab and our grades were dead on graded with a laser grading box. The more I think about it the more I think he was complaining about nothing. We do not place or Finnish just the prep work.


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## jmacd (Jul 14, 2009)

cdkyle said:


> Sounds pretty good to me. Do you ever have a call back or come up short?


No call backs on our work in a very long time and many floor preps and parking lot preps for asphalt. I try to not hand over the work to the next guy until we all agree the elevations or grades are correct. That way I try to cover my but.


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## backhoe1 (Mar 30, 2007)

Exactly the reason I won't do concrete or slab prep.


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## Calidecks (Nov 19, 2011)

I was a Laborer for several years as a young buck for a commercial GC, that was my job to make sure the backhoe didn't dig too deep and finish grade was spot on. It was a fire-able offense to phuck that up. It adds up on huge commercial buildings.


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## shanewreckd (Oct 2, 2014)

Californiadecks said:


> I was a Laborer for several years as a young buck for a commercial GC, that was my job to make sure the backhoe didn't dig too deep and finish grade was spot on. It was a fire-able offense to phuck that up. It adds up on huge commercial buildings.


Chit I still have to do that and I'm a journeyman carpenter and a lead hand. Depends on the dirt crew we have with us, or how well the labourers do. Couldn't tell you about a set number for overages but to me, you seem to be pretty bang on for a 90+ yard pour. Guys just being cheap :laughing:


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## cdkyle (Jul 12, 2009)

jmacd said:


> No call backs on our work in a very long time and many floor preps and parking lot preps for asphalt. I try to not hand over the work to the next guy until we all agree the elevations or grades are correct. That way I try to cover my but.


I think you missed my point. When I say call back, I mean the clean up load to finish the job. 

Say for instance the redi-mix supplier has 9 yd trucks. The job figures 48 cy. You order 45+ cy. The remaining 3 yards would be ordered at that time. That is the call back or clean up load. Instead of just ordering 54 cy, which of course would be 6 cy over. 

Sounds to me like you done your job correctly. Just sounds like the builder's/GC's concrete guys are over ordering. :thumbsup:


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## muskoka guy (Nov 16, 2013)

I would say if the gc accepts your work as is, its his problem after that. Its like the painter complaining about the drywall after he has painted it. The other factor you cannot account for is the rip off factor from the concrete company. I have had many pours come up short when you know you have calculated correctly. We did a school years ago and the concrete company owner would come and look at ever pour before he shipped the concete. We were always short. One time he didn't come to see what we were pouring and we were a metre short on a square box form on a footing. When he came over after words and did the math himself, he said the batcher must have made a mistake and didn't make us pay for the balance. You can only take their word for it when they say there is 9 yards in the truck.


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## jhark123 (Aug 26, 2008)

This guy is either a newb or and azz hole, either way don't sweat it. 5 yards on a 90 yard pour is fine. If this guy doesn't allow waste in his bids he won't be in business long.


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## superseal (Feb 4, 2009)

I'll figure in 10 percent overages on every pour I do,...doesn't matter if it's 2 yards or 200 yards.


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## shaper (Apr 24, 2006)

I own a laser box blade and have done several commercial floor subgrades. A few of them were over 100,000 square feet. The GC and myself would set up the rod on the agreed to benchmark. At the end of the day after prepping around 40,000 square feet we would both check several dozen spots. Most times the laser box would get +/- one hundredth of a foot or .01 which is equivalent to 1/8" This can vary depending on the size of the material used. So with those tight tolerances that would be an extra 14 cubic yards of concrete over 40,000 square feet. Not sure but I bet the concrete finishers can't get their tolerances and tighter than what the laser box can. I would take some readings on their finished floor


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## ajbackhoe (Nov 26, 2006)

If it calls for a 4" slab I set my laser to grade for a 3.5 or 3.75 slab. The GC is always happy and impressed when he saves money on concrete and never complains that his slab is not thick enough.


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## pizalm (Mar 27, 2009)

ajbackhoe said:


> If it calls for a 4" slab I set my laser to grade for a 3.5 or 3.75 slab. The GC is always happy and impressed when he saves money on concrete and never complains that his slab is not thick enough.



And you can save money on rebar going up a spacing. 16"'isn't needed, go to 24" o/c....


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## dayexco (Mar 4, 2006)

pizalm said:


> And you can save money on rebar going up a spacing. 16"'isn't needed, go to 24" o/c....
> 
> 
> Sent from my iPad using Tapatalk


rebar spacing would all depend on what the engineer/architect spec'd. all site prep jobs i did...i had the GC do a walk through with me, he'd either accept/sign off...or point out the deficiencies in the grade..we made it how he wanted it, from that second on, it was his. i didn't care how much concrete it took.


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## jmacd (Jul 14, 2009)

dayexco said:


> rebar spacing would all depend on what the engineer/architect spec'd. all site prep jobs i did...i had the GC do a walk through with me, he'd either accept/sign off...or point out the deficiencies in the grade..we made it how he wanted it, from that second on, it was his. i didn't care how much concrete it took.


Thanks for all of the reply's. 

First off I would never prep for 3.75 when it calls for 4". My goal is to get the prep work as close as possible. I do prep 1/2" to 1" high depending on base material for compaction though. You can loose a 1" easy after compaction. 

On asphalt work I have witnessed the testing company core drill the parking lot to determine if the thickness of the asphalt and sub base was thick enough. On all of my concrete slab preps the testing company is there measuring slab thickness so would not want that either. 

As far as having the GC check grades I have always made that a must do before we move on, so what Dayexco wrote is exactly what we do.

They pored another 100 yards today and we were less than 3% over. The GC was like an old friend today :laughing: 
I think the GC was having a bad day and needed someone to complain to and I guess it was my turn. So I made more out of it than I should of. 

I am just not used to hearing complaints on this type of work we do because of the investment I made for the LevelBest grading box I bought. Like said already it gets you closer, faster than any method I have used prior.:thumbup:


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## pizalm (Mar 27, 2009)

dayexco said:


> rebar spacing would all depend on what the engineer/architect spec'd. all site prep jobs i did...i had the GC do a walk through with me, he'd either accept/sign off...or point out the deficiencies in the grade..we made it how he wanted it, from that second on, it was his. i didn't care how much concrete it took.



It was sarcasm to go with him saving the GC money by selling a 3.5" slab as a 4" slab. 


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## Jay hole (Nov 12, 2013)

I've always wanted to build a box that will hold exactly 3 yards of concrete, and order three yards just to see how close they are....


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## Calidecks (Nov 19, 2011)

Jay hole said:


> I've always wanted to build a box that will hold exactly 3 yards of concrete, and order three yards just to see how close they are....


This is a great point. When I've ordered 6 yrds. How do I really know they sent six yards? There's been times I swear they short the load.


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## Walraven (Jan 24, 2014)

Californiadecks said:


> This is a great point. When I've ordered 6 yrds. How do I really know they sent six yards? There's been times I swear they short the load.


We had that to definatly shorted us was a terrible load runny as pump mix and sort by a metre at least, then the driver tells us there'ssomething broken at the plant an their mixing by the scoop instead of weight


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## CConcreteEx (Oct 19, 2010)

Jay hole said:


> I've always wanted to build a box that will hold exactly 3 yards of concrete, and order three yards just to see how close they are....





Californiadecks said:


> This is a great point. When I've ordered 6 yrds. How do I really know they sent six yards? There's been times I swear they short the load.


Two things, tell them you want the batch weights sent with you ticket. After reviewing them for a few weeks you'll start to see whats normal target and whats not. Also, if you get your concrete tested that day, tell them to do a yield test. The tester can figure this out with the batch weights and will tell you if your load is on target, over yielding or under yielding.


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## Nac (Apr 16, 2006)

We where doing a underpinning job once had to call a different supplier be cause everybody was busy. It was a short load company with these little trucks 3cy mixers. I need 3cy it was formed in a timber lagging 3'x3'x9' exactly 3 cy. we poured and it was 1/2 cy short. I checked the ticket it was batched as 3 cy called the plant and he said that 3x3x9 is not 3 cy when he checked on his slide ruler. Last time I ever used them.


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## tgeb (Feb 9, 2006)

I work with a guy that owned a company that did residential tract homes, and they would do many of the exact same home model/design each year.

This particular foundation would take X number of yards of concrete, no more no less, darn if every now and then they would be heavy enough to run a yard or so in the next footing, but sometimes they would come up short.....same foundation, same forms, same crew....


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## fjn (Aug 17, 2011)

Batching concrete is very subjective to say the least. Order a load the day after a heavy rain,you will come up short every time,water weight of sand and stone.


I have a rather large steel precast table 10' x 40'. I have formed panels using 2" x 10" s and figured a full 10" (when in reality it is not) rounded the volume to next highest yard and still came up short. Called the dispatcher hot as a firecracker,he said your grade is off I said cut the B.S grab your best tape and come to job site. I will buy your whole plant lunch if I'M wrong. He comes over and said I guess we screwed up.:laughing:


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## fjn (Aug 17, 2011)

Jay hole said:


> I've always wanted to build a box that will hold exactly 3 yards of concrete, and order three yards just to see how close they are....





I guaranty it will be different every time !


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## HardWorks (Aug 6, 2014)

We measure my cubic volume they batch it by weight. Did a power house job back in 1999-2000. I had a little pour at the start it was dead on 9 yards ordered 10 and still came up short. Figured it was going to cost us about $300,000 over at that rate. LOL

Went to the plant, (south Philly) it was like stepping into the Godfathers office. I came away with two Tonka concrete trucks painted like the companies trucks. I set them down on the PM's desk and said each one of these trucks is worth $150,000. LMAO

It the part of the game. If a GC said anything to me about 5 yards on a 90 yard pour, I'd tell him to go pound sand. 

I never ever come up short because I order more... always. It is cheaper to pay the extra yard than it is to pay the OT waiting for the clean up of coming up short. Short load, the wait, the man power and the chance of a cold joint. Not worth it. 10% over no matter what the amount is.


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## Little (Jul 22, 2006)

5% overage is completely acceptable. Just think of how much more time you would have to spend on a large building floor pour to get it tighter. Especially on clean stone like 3/4" where it moves soo much when grading. And as stated before, know your material and how much it will compact so you can adjust initial grade accordingly.


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