Concreting calculations

[Specialized29er]

Hi Guys, I'm looking to buy a 1/2 decent cement mixer instead of hiring one because at our new property I'd like a couple of 7 x 4m slabs and footings concreted and I'm trying to work out whether a 4 or an 8 cu ft mixer would do. Depending on the price compared to the amount of loads required with a couple of labourers helping.
I'm trying to convert 4cu ft to meters and have googled it and I keep getting 0.11 meters but 1/10 of a meter doesn't look right.
Would anyone know how to go about doing the conversion.

8 cu ft 18.jpg $2,600 4 cu ft 7.jpg$470

[Picko]

0.1132672 cu m

[aldav]

1,000 (1 metre) / 304.8 (1 foot in mm) = ANSWER (1 metre expressed in feet)
ANSWER x ANSWER x ANSWER = a cubic metre in cubic feet
4 cf / a cubic metre in cubic feet = the proportion 4 cf is of a cubic metre

[Wrongwayfirst]

Yep you got it, it might not look right because one may list max fill level and the other mixer may list total volume.
A 200 litre drum = 44 gal so 1/2 of a 44 looks about right for a cement mixer

us gallon = 3.3 litres
uk (aus) gallon = 4.5 litres
1 cu ft = approx 28 litres = 6 aus gallons

28 x 4 = 112 = 0.11 cubic metres

cheers

[Bushmiller]

Specialized

In deciding the size to go for I am making an assumption that you will be tipping the concrete into a wheelbarrow. I had always worked on the assumption that a builders barrow held 5ft³ with some concreters barrows (they are longer and narrower ta aid in pouring) at 6ft³ . However a quick Google search indicates a builders barrow is between 85l (3ft³ and 120l ( 4.24ft³). 120l of concrete weighs close to 250Kg. Just some figures to toy with.

Your slab will require about three and a half tonnes of aggregate and around twenty five bags of cement (20Kg bags) and maybe 400l of water. The reason I know some of this is that I have just poured a slightly smaller slab for an oversize lawn locker at 7.6m x 2.3m. If you are doing it by yourself (not recommended) the smaller concrete mixer will be adequate! Be sure to start at first light.

P1070737 (Medium).JPG

My mixer is very old, but will overflow a "builder's barrow." (larger size)

P1070731 (Medium).JPG

There was a time when it could be towed on the road behind your vehicle, but I have never done that on the open road.

P1070735 (Medium).JPG


Good luck with the pours. Young fit help is of the essence.

Regards
Paul

[Beardy]

I don’t if it is feasible to consider readymixed concrete in your location but it saves a lot of heartache and a better opportunity to get a consistent finish on the slab

[Specialized29er]

Thanks for the help guys and no the nearest readymix is 160klms away and the transport costs are crazy so while in the city yesterday I bought a Wel-Bilt 4 cubic foot mixer and got the Honda petrol motor one at a bargain price.