I'm building a "SHED" and am about to start mixing concrete for the base. I've put down about 6" of hardcore and scalpings,
and have about 5" for the concrete. I will be storing the Locost in it when finished, along with my lathe. I'm trying to find out the best
ratio to use but am getting conflicting advice.
So far it's:
Cement : 1
Sand : 2
Gravel : 4
or:
Cement : 1
Sand : 1
Gravel : 2
Any advice would be great.
Regards, Ian.
5 ballast - 1 cement.
that what mine is.
Mix A: 1 part cement, 2 and a half parts damp sand and 4 parts coarse aggregate.
Alternatively 1 part cement to 5 parts mixed aggregate ( half inch to dust).
This mix is suitable for thicknesses of 3" and over, ie; drives, floor slabs and foundations.
Mix B: 1:2:3, cement, sand, aggregate or 1 part cement to 3and a half parts mixed aggregate. This is a stronger mix and is used paths and small
sections or slabs less than 3" thick.
If dry sand is used ( it is normally supplied damp), reduce the amount for mix A by 20% and mix B by 25%.
[Edited on 14/4/07 by Confused but excited.]
Don't forget to 'blind' the base hardcore with sand and put a layer of 250um polythene damp proofing membrane on top of the sand before
filling with concrete.
HTH
Mal
5:1 (3+2 or ballast as stated)
Cheers
Alex
Hi
My brother does this for a living (ground worker)
He says,
When I order readymix it's 1/3/6 for drives, floors, & footings.
1/2/4 for anything that requires reinforcing.
That's Portland cement / sand / stone.
(not masonry cement from DIY stores)
The stone makes no difference to the strength of the mix, but too much stone makes it harder to get a finish.
Hth
Paul G
I would not worry about the science that much, a standard small mixer takes 1/2 bag of dust then fill with ballast, around 10 shovels from memory.
The bags are sized to make it easy.
Regards Mark
You don't get as much cement on a shovel as you do ballast so it's all guesswork anyway unless you actually use buckets to load it in. I use
the plenty to one mix same as the builders round here
My Dad was a builder & he always told me 1:2:6. for drives, etc. Remember to use sharp sand for concrete.
As the mix ratio's are pretty much confirmed the best other bit of advice is here
quote:
You don't get as much cement on a shovel as you do ballast so it's all guesswork anyway unless you actually use buckets to load it in.
quote:
Originally posted by ecosse
5:1 (3+2 or ballast as stated)
Cheers
Alex
Thanks all.