How big is a bag of ballast?

[camerart]

Hi,

In case someone is estimating ballast and cement for a concrete mix.

I ordered a large bag of ballast from Travis Perkins, thinking it was 1ton, plus 10 bags of cement which would give me 4:1 mix. Not so it measured .8 x.8 x.8mtr, which calculates 1/2 mtr. I needed extra small bags of ballast to give 4:1. I think they should have noticed the amount of cement I had ordered and advised me.

Next B&Q. As I went in, I asked someone in the trade department how many bags of cement to one of their un-marked 'large' bags. He said 4:1 mix needs 4 of ballast to 1 of cement. Again, not so. I needed extra ballast to make it up. I think the ballast is 20Kg.

P.S. One the B&q bags it says buy 10 or more for a reduced price, I got 16P reduction for 16 bags.

All very annoying. (I hope I have given correct information, so don't sue me )

cheers, Camerart

 

[Watshot]

A 'tonne', or large bag, is generally 850kg, they won't list it as a tonne for that reason. The equivalent in small bags would be in the region of 35 for the same weight.

To be fair, it's not their job to second guess what your project is, or whether you are mixing at 4:1 6:1 or any other figure. You may have had plenty of cement left over from a previous job. Far too many scenarios for them to be questioning every order.

 

[jeds]

A 4:1 mix is measured by volume - not weight.

 

[camerart]

A 4:1 mix is measured by volume - not weight.

I did say that the Travis Perkins ballast bag was app 1/2 Mtr, and I did try the B&q bags in a container comparing ballast with cement, before mixing.

It's all not very clear with big bags, large bags, 20Kg and 25Kg mixed together, and like most people, we want to get on with it, not weigh and measure stuff.

C.