Just checking concrete slab calculations.

[duke666]

I am pouring a concrete slab for a new shed in a few weeks time and just want to check I'll be ordering enough materials.

The slab is 3700mm x 1860mm x 150mm and I'm ordering 2 off 850kg bags of all in one ballast and 14 bags of cement.

Scalpings are already in place to 75mm.

Thanks.

 

[Alastairreid]

http://source4me.co.uk/calculate_concrete_mix.php

 

[Andyc84]

Assuming you are mixing in batches on site, it may well be best to get a few more bags of the cement, which can then be returned if not used, that way you will have sufficient supply and can take account of variations in the ratio as needed.

 

[duke666]

@alastairreid, thanks, turns out my original calculations were spot on, may be a little too spot on....

it may well be best to get a few more bags of the cement, which can then be returned if not used

Good idea, I think I'll be getting a few cement and ballast just in case.

Thanks for the replies.

 

[duke666]

One other quickie, does my slab actually need to be 150mm thick? It's having a 12 x 6 wood shed on it and and I'm also adding a piece of A142, so I'm thinking 150mm may not be necessary???

 

[Alastairreid]

100mm would plenty for a shed.

 

[duke666]

Thanks.