Need help for my project. working out cement/ballast

Discussion in 'Builders' Talk' started by turbo2015, Nov 24, 2017.

  1. turbo2015

    turbo2015 Member

    Hi needing help please

    for my project i need to lay down oversite.

    6m x 4m 100mm depth how do i calculate how much cement bags and how many 1 ton ballast bags.

  2. KIAB

    KIAB Super Member

    2.4 cubic metres, looking at ready mixed concrete, easier.
  3. stevie22

    stevie22 Screwfix Select

    Go for a mobile batcher rather than a "proper" readymix truck as no waste and more time.

    For oversite the lads with a big old mixer on the back of a tipper will be more than good enough.
  4. leesparkykent

    leesparkykent Well-Known Member

    1:2:4 mix

    768kg of cement
    1440kg of sharp
    2880kg of aggregate

    422 litres of water.
    KIAB likes this.
  5. KIAB

    KIAB Super Member

    Last edited: Nov 24, 2017
  6. Isitreally

    Isitreally Super Member

    How have you come up with the amount of water????

    You wouldn't have any idea how much moisture there is in the sand before you start, unless you are basing it on being bone dry.

    Any how for an over site, all in ballast is much easier the mix at a rate of 5.1.

    So about 4.25 tonnes of ballast and 1 tonne of cement (40 bags).

    But as said above, get someone like easy mix or the likes to mix it on site, you only pay for what you use and it wil be done in an hour or so as opposed to most of the day.
  7. yorkshireboy

    yorkshireboy Member

    Two or three inch is plenty for over site if you've got visqueen under it.Two ton of ballast mixes about a metre square if that is any help.
  8. turbo2015

    turbo2015 Member

    Guys your right will be going to readymix already saved a load on labour by doing most of it myself.

    The floor type is floating timber with insulation between joists . would 1 inch crushed concrete and 1.5inch concrete do the job for signoff. do i need to lay any dpm? before the pour?

    i have a soil pipe running down the extension do i just let the concrete bury the pipe?

    Thanks Again
  9. yorkshireboy

    yorkshireboy Member

    Get it roughly level,spread a thin layer of sand and lay your dpc membrane on the sand overlapping the joints.Cover this with at least 50mm of concrete roughly flattened with a shovel.Make sure there's at least 150mm between the concrete and the underside of your joists.Not sure what you mean about the pipe.

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