I Got The Concrete Quantity Wrong

But it worked out! This is how you calculate your concrete quantities...!

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[SketchyRacer]

Don't under estimate how much variation from the concrete suppliers too. It's measured by weight which means that additional water (think a sloppy mix for pumping) will change the wet density and then the calculated volume by mass. I had a pretty decent argument with my concrete guy about this as I was filling 1m3 forms so knew exactly how much I needed per form and under supplied by 30%. I told them I don't care about the density difference as they sell it per m3 so if I order 4m3 I expect a minimum of 4m3.

[adrian]

Did you ever think the concrete guys short changed you, your maths over estimated your volume substantially. You should have had plenty left over!

[DebacleWhimsical]

Always a pleasure watching the Casey Neistat of builders doing his thing! Almost therapeutic for some reason.
Wish the episodes were longer and per project.

[GoodNeighborJon]

Wow Scott! I don’t know how they taught you in NZ, but in America, it’s pi times the radius squared, times the depth of the hole. I always get the exact right amount. Don’t subtract the post volume, and add only 10% waste. Been doing this almost 30 years now and haven’t screwed it up, yet.
Cheers, mate!

[Matt_OG]

Amazing to me that these uploads go live at 4:30am but im still awake to watch whenever i get the beautiful notification! Loved the video.

[bar]

Maybe I missed something, but I'm surprised you came out short, because you calculated volume for a cuboid instead of a cylinder (square vs circular base), so your example calculation is off by 0.07 m3 more concrete (about 27% more concrete on every hole).
So either wastage was much higher than you estimated or there was other error I can't see.

[NRG]

Ya live, ya learn. It's awesome that you can admit when you are wrong. Not many people can do that in this day and age, especially on social media.

[robohjhonson]

Hey Scott man I’m 13 and from Australia SA, keep up the great content and I love your style your so good at carpentry and it inspires me to get some sort trade.ps I want to eat chef paerous food I’m sorry if I spelt that wrong haha

[soccovitch]

The Chef would have said, "Bro, recken we are a bit tight on the concrete, ya, bro?...but she be right, bro...all good." Great vid man.

[jackthomson]

Hi mate. 20 years exp in fencing in outback Queensland and a rule of thumb we used for ordering concrete for round holes was divide the square cube amount by 14 and x x 11. Add 10% and round up to next .2. Never ran out in 20 years and normally little wastage. Overall congrats on a great job 👍Cheers. Jack and Mandy from Mount Isa

[xqq]

My concrete pump guy suggest all holes size add 30-50mm to the hole size. When the digger pulls the auger out off the holes, it creates the holes bigger. Small jobs will not be a problem, but at a job, I ordered 18.5m and it used 24m at the end. The 50mm extra dimension makes a huge difference. It works every time. Good video! Well done!👍

[MsElijah]

Throw in some old pieces of concrete or bricks to bring the concrete level up a bit.

[lemonadetycoon]

Watching you do the concrete calcs and there i was sitting on my dining chair screaming MATE!!!! DON'T DO IT!"

[alexosullivan]

Hi Scott love the videos. In England we have lorries that mix the concrete on site so you only pay for what you use. Very handy when it’s difficult to add up volumes. Not sure if you have them in New Zealand but I’d highly recommend

[chrisdonnellybuilder]

I've found concrete plants get quantities wrong, won't mention any names, one year we were short by a whole truckload, according to the supplier, but the thing was our slab, even though it was a random shape it was consistently built and the volume was calculated from the 3d drawing, so to say we were a truck short didn't stack up. Also a year later same company, we were about half a meter short on a not very big pour, really simple to measure when it's an oblong. The truck driver got angry when he was sent back to top it up. the truck drivers were doing the batching themselves, found out through a workmate on another job same truck driver was short for them, and again simple oblong shapes, always adding a wastage percent too. But on a POSITIVE :) we always have a competition who can guess the amount the closest before its measured. Some just make a guess others use the "eyecrometer" to guess, always fun :) good work, the retaining wall mission is almost done huh?

[David-xuyk]

I've always wondered how you figure out how much concrete you need. You explained it nice and clearly!

[anAwesomeFilipino]

One of the reasons why I’m leaving my architecture job and joining the trade! Thanks, Scott (and Paeru)!

[MrXxing]

Not many people will pump the water in these day. Great Job Scott.

[markcarter]

Expected to see Pi in the calc somewhere. Radius squared x Pi x depth = volume of cylindrical hole. Pi is approx 3.142 😮

[SebastiaanMollema]

As always a great and enjoyable video! Is there not an concrete strength issue because there is no plastic lining (for instance) between the dirt and the poured concrete? Here in NL it is always good practice because the wet season makes the concrete to wet and dry season to dry. And doesn’t the concrete crack under the tension of the wood wet/dry contractions? Here it does with that size of pine timber posts but for fences and other esthetic structures that does not matter much.