How much concrete?

Discussion in 'Builders' Talk' started by Martin Joiner, Apr 23, 2010.

  1. Martin Joiner

    Martin Joiner New Member

    Ok, so i've got 2 concrete slabs to lay, one is 5.4m x 5.4m and the other is 5m x 5m, both 4" thick.

    Q1. how much concrete will i need, i get it to around 3 cube per room.

    Q2 this is the killer, because of where i'm doing this we can't get a premix in so it's got to be done by hand so how much sand, stone and cement am i gonna need.

    Q3 where can i get a new back from when i've done all this mixing lol


  2. ian anderson

    ian anderson New Member

    Have you thought about using a concrete pump?

    It is a smallish job for them, but if times are a bit slack it might be worth getting a quote.

    Sure save a lot of mixin!

    Otherwise, I used to allow about (35 CWT) appx (1.5 tons) of ballast per M cube. Then divide the total depending on what mix you need (1:6) for a slab. So 35 divided by 7 (6+1) means that you need 5x50kgs of cement and now of course we have baby bags so its around 10 bags.

    If you end up with cement over its because no one EVER puts the same size cement shovels in as ballast, resulting in a weaker ratio!

    Heap that cement up!
    Good luck
    Most days you can find me pottering about at <u>Flip Over Saw Stuff</u>,
    part of <u></u>.
    Come on in, I'll go and put the kettle on......
  3. Measure2cut1

    Measure2cut1 New Member

    There are various companies which mix concrete on site and barrow it in for you. Mix a mate is one example.
  4. ÜÜ­

    ÜÜ­ New Member

    Only a complete dipstick mixes their own concrete nowadays, especially 6 cu/m. Get Mixamate or one of the other 'mix on site' trucks. Look in Yellow Pages, there's loads of them. About £95 per cu/m, 20 minutes allowed per cu/m. No waste, never short, no mess. Have exactly what you need to the nearest barrow full and only pay for what you have.

    No brainer.
  5. Martin Joiner

    Martin Joiner New Member

    Thanks i'm gonna need it lol
  6. Martin Joiner

    Martin Joiner New Member

    No brainer.

    For starters i'm not a dipstick.

    The job is in France, access for anything wider than 7 foot stops 100 yards away from the house, materials can be delivered from local builder on a small van, hence i'm doing it by hand.

    I have the time.
  7. ÜÜ­

    ÜÜ­ New Member

  8. Martin Joiner

    Martin Joiner New Member

    err cost
    err time
    err lets block the village for a day
  9. hallbeck

    hallbeck New Member

    Rent 3 muck trucks (powered wheel barrows)

    Should have it done in a couple of hours
  10. doing a bit

    doing a bit New Member

    well its 2.5m and 2.9m , what ratio are you looking at ? 1:3:4 ??
  11. ÜÜ­

    ÜÜ­ New Member

    err....You seem to know it all but can't work out how much material to buy.

  12. mcmuck

    mcmuck New Member

    UU UU, UU UU, you some kind of seal. If you have nothing positive to say why not just not bother at all. I do not get the time to worry about grammar, paragraphs and the queens english. Unlike peasants like U, UU, UU, UU!
  13. ÜÜ­­

    ÜÜ­­ New Member

  14. the old un

    the old un New Member

    Martin, Let me try to answer your question for you.
    I do not think you are a dipstick in batching on site. Aprox 50% of the concrete we lay, we batch on site, either for practical reasons or from cost analysts. Any one who states that nobody batches on site these days, clearly has no knowledge of the heavy side of the industry.
    Your first post quite clearly states that your can not use a volumetric mixer or capacity drum mixer.
    We assume that you are laying two concrete oversites to two rooms either in new build or a refurb to existing.
    You require approx 5.5 m3 mixed concrete to place. you require 1-2-4 mix for oversite concrete.
    As I do not know how they sell aggregates in France I will list your materials as follow,
    Cement approx1750kg. 70no 25kg bags.
    Grit sand (concrete sand) approx 3500kg.
    Stone (gravel) 38mm down to 10mm, approx 6500kg.
    Or if they sell all in ballast in France.
    Then all in ballast 10 tonne.
    You may be a couple of bags dust short or a couple of barrows short at the death, due to the material volume loss after mixing. Depends on what mixer you are using.
    Note!!! I have not used the word jumbo bag, bulk bag etc, as so many people call these tonne bags, but in fact they are not. 9 out of 10 jumbo bags, etc, hold 850kg. This is the minimum weight that the suppliers have to put in them to comply with the TDA. The tonne description is the assumed weight for lifting and carriage purposes only.
    Hope this helps. Guidance only.
    old un.
  15. mcmuck

    mcmuck New Member

  16. ian anderson

    ian anderson New Member

    Martin, I agree with the 'old un' I have also lost count of how much hand mixed concrete we have mixed on tight access period jobs.

    Also agree that 9 or 10 Tons (1000kgs) will do it (my calcs came out at 8.7 tons all in ballast). I get a few bags less at 66 x 25kgs.

    Neither here nor there, plus or minus 10%, it all depends on how accurate the prepped base is! Are you laying over polystyrene?


    p.s. I also don't see the point in 'mud' slingin on here, if your bored go and do something else!
  17. ian anderson

    ian anderson New Member

    Sorry, that should read as 9 or 10 TIMES 1000kgs so getting on for 10,000kgs in total.
  18. 2bsure

    2bsure New Member

    martin, just go to your local tout faire, give them the floor size and slab thickness and they'll sort it all out for you. all-in ballast is readily available. cement comes in 25 or 35 kg bags. the 35kg bags work out way cheaper. also you'll probably find that they'll base their price on using lafarge classic cement. nowt wrong with it, just a bit pricey. they ALWAYS carry a stock of cheaper cement for artisans, still made by lafarge but can be 60-70 cents a bag cheaper. for the amount of gear you'll be needing youre looking at 2 lorry loads and a 3.5t flatbed, so you're going to need to 'discuss' the delivery charges.
  19. wiggy

    wiggy Screwfix Select

  20. Martin Joiner

    Martin Joiner New Member

    Thanks for the help and advice guys, worked the costs out on a french site and will come to around 750 euros, have also recently been given info about a company that will deliver premix for 85 euros a cube, just need to speak to them about the access now.


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