How to calculate amount of concrete required?

[jainlal]

Hi Mitch

Mate, using that concrete calculator for area [1.41m x 0.51m x 130mm] L X W X D repairing driveway cutout, it stated that i need least 11 x 20kg bags.

My question is based on what I've read in your previous reply to another customer, 1 Concrete, 2 Sand & 3 Gravel, how do you input those into this calculation [volume], do i divide these by factor 2 or 3 now as Sand and Gravel will take that volumetric space and say i will only need 4 bags now.

[MitchellMc]

Welcome to the Bunnings Workshop community @jainlal. It's brilliant to have you join us, and many thanks for your question about concrete quantities and ratios.

If you need eleven bags of concrete for the area, I suspect you'd be very close to needing two cement, four sand and six gravel for the same volume. However, for the sake of not having to run back to the store mid-pour, I'd grab three cement, five sand and seven gravel, just to be safe.

Please let me know if you have any questions.

Mitchell
 

[jainlal]

Thanks Mate, will do that.