About to lay a concrete slab for a shed base and just wanted to know if a ton bag of mixed aggregate (sand & 20mm gravel ? ) will be enough for a 10ft x 6ft x 3ins depth - also how much cement will I get thro for a 5-1 mix ? Apologies but not so good at the maths :-( Probably someone here has done a similar size & can advise etc. Cheers
Quickie Question on material amount
Mar 26, 2008
4 Replies
That's just over 0.4 of a cubic metre of concrete, so a tonne of ballast should just about do it.
Our old friend Cormaic has handy calculators for working out quantities of concrete and its ingredients at
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a C20 mix (1:2:4) he reckons you'll need 130 kg or so of cement, so get 5 or 6 bags.
3m x 1.8m x 0.1m = 0.555 m2 so he'd need another half-bag to be safe (unless you're relying on the cement to make up the difference?).
Sure, but the OP did say 3 in. thickness, not 4 in. / 100 mm. Sounds a bit thin, but it is only a shed base and if it's well supported on compacted hardcore it might be OK.
Cement fills the interstices between the particles of aggregate and does not significantly bulk out the volume.
Thanks for replies Its one of those metal type sheds ( no floor ) so I thought 3ins depth would be sufficient ? Thought about putting hardcore layer down first ( 20mm aggregatecompacted ) Any advice on laying a damp proofing membrane ....
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