Currently doing fence posts and some small concrete pads around the house so I need to self mix the concrete

I keep searching for this type of thing on the internet:

Here is a good example of what is required from Boral’s Site

From my learnings:

1 Cement 2 Sand 3 Aggregate (gravel) is too strong. 16bags (costly)

1 Cement 2.5 Sand 4 Aggregate is OK for fence posts. 13bags of cement per cubic metre.

The more cement the more costly of course so don’t over do it.

**Note:** These are 20kg bags of General Purpose cement.

Can you assist by confirming how many 40kg bags of cement do I need per cubic metre volume?

Thanks

If itโs 13 bags of cement for 20kg bags it will be 6.5 bags of cement for 40kg bags.

Are you sure that’s 20 kg of cement per bag james?

I’m not sure if I understand exactly what you mean, but in Australia the standard weigh for a bag of cement is 20kg.

How many 20kg general purpose ready mixed concrete bags do i need for .56 cubic metres

If it’s 13 bags of cement for 20kg bags it will be 7.5 bags of cement for 40kg bags.

I found from Boral 1m3 of cement you need 108 20kg bags (54-40kg) premix bags or For a one 20 kg bag equals 0.01m3.

This should be easier to understand.

Great thanks Jarod

How many bags of concrete do I need for a 3.1m x 3.1m x 110mm slab?

C’mon Allan – thats just lazy ?

3.1 x 3.1 = 9.61m2 x 0.11 = 1.05m3

James’ estimates for 1cubic meter will be close enough for your slab.

Thanks Drew ๐