Any builder members know how long concrete..

Discussion in 'OT (OFF Topic) Forums' started by HughJarse, Dec 20, 2008.

  1. HughJarse

    HughJarse Hardcore MB Enthusiast

    Messages:
    1,035
    Joined:
    Sep 13, 2006
    Location:
    North East
    Car:
    c250
    ...takes to dry out?

    Just had a conservatory built and Im not sure how long concrete takes to dry before you can floor over it ??
     
  2. Spinal

    Spinal Hardcore MB Enthusiast

    Messages:
    4,793
    Joined:
    Sep 14, 2004
    Location:
    Uxbridge
    Car:
    Smart, S320 and C180 with 3-pointed stars amongst others
    I may be wrong, but from what I remember (and this was a good 10+ years ago when my father had a few warehouses built) the concrete took about a week to dry, but was kept constantly wet to "cure" it...
    M.
     
  3. The G.F.P

    The G.F.P Hardcore MB Enthusiast

    Messages:
    1,292
    Joined:
    Jun 9, 2008
    Location:
    Cambridgeshire
    i though concrete had a half life of around 6 billion years

    by which time the earth will have been eaten up by the sun going super nova

    or was it about a week

    i always get them two mixed up
     
  4. whitenemesis

    whitenemesis MB Club Veteran

    Messages:
    15,807
    Joined:
    May 7, 2007
    Car:
    Lexus RC300h F-Sport 2019
    Only sure way to know is to place a piece of polythene over it and when there is no more condensation underneath, it's cured ... Or was that for rising damp??
     
  5. The G.F.P

    The G.F.P Hardcore MB Enthusiast

    Messages:
    1,292
    Joined:
    Jun 9, 2008
    Location:
    Cambridgeshire
    i think thats for atheletes foot/feet
     
  6. whitenemesis

    whitenemesis MB Club Veteran

    Messages:
    15,807
    Joined:
    May 7, 2007
    Car:
    Lexus RC300h F-Sport 2019
    :eek: BIG feet!!
     
  7. grober

    grober MB Club Veteran

    Messages:
    26,487
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
  8. Darrell

    Darrell Hardcore MB Enthusiast

    Messages:
    3,562
    Joined:
    Dec 15, 2006
    Location:
    Back in Mill Hill but sometimes in Skiathos
    Car:
    A Jaaaaag, 2016 Dacia Duster and a 2004 Carrera (996)
    Normally we would leave a concrete floor for 3 to 4 days then screed it.We would then leave the screed for about a week, then it was ready for tiling or a laminate floor.

    In laymans terms,the concrete was the stuff that came out of the mixer (hand or pumped) and levelled pretty well.The plasterers or screeders would then cover that with betwen 50-75mm of screed.This is made up of course sharp sand/cement and can be levelled to within a mm.This is the best surface to put tiles onto.If you are building your conservatory to building regs then your district surveyor will advise you.
     
  9. miro

    miro Hardcore MB Enthusiast

    Messages:
    3,444
    Joined:
    Mar 1, 2004
    Location:
    Sydney NSW Australia
    Car:
    W203 slightly modified
    Concrete takes about 3 years to cure. 90% of which is achieved in several hours. The curing time is also affected by the moisture level in the first 3 days.
     
  10. miro

    miro Hardcore MB Enthusiast

    Messages:
    3,444
    Joined:
    Mar 1, 2004
    Location:
    Sydney NSW Australia
    Car:
    W203 slightly modified
    The floor levelling product from 3M is very expensive but does all the levelling itself.
     
  11. Mudster

    Mudster Hardcore MB Enthusiast

    Messages:
    2,509
    Joined:
    Sep 4, 2006
    Location:
    Surrey
    Car:
    2008 A150 SE Classic, 2007 Saab 9-3 Sportwagon
    Sand/cement screed should be allowed to dry for 5 weeks before tiling (building regs). In reality, 3 is usually enough, they are usuakky still shrinking for the first 2-3 weeks

    Concrete pads, depends on thickness....
     
  12. miro

    miro Hardcore MB Enthusiast

    Messages:
    3,444
    Joined:
    Mar 1, 2004
    Location:
    Sydney NSW Australia
    Car:
    W203 slightly modified
    Is that a sand and lime based method ? I saw it being used in "eco-homes" where they went back to traditional methods. It starts off as chalk and gradually turns into stone.

    Ok now I understand why the 3M product is so popular. It only takes a few days.
     
  13. Uberwagon

    Uberwagon Hardcore MB Enthusiast

    Messages:
    753
    Joined:
    Jul 29, 2006
    Car:
    1991 500E
    When we install a generator (big ones) the base is left for 4 weeks before any work is done on it.

    Dave!
     
  14. rf065

    rf065 Hardcore MB Enthusiast

    Messages:
    3,624
    Joined:
    Jun 8, 2007
    Location:
    Grossbritannien
    Car:
    SLC300 - C250d Estate 4 Matic & Z900rs
    The Hoover Dam was completed in 1935 & the concrete is still curing to this day! They calculated that if it was poured in one go, it would take 125 years to cure. Best wait a while before walking on your new floor :rolleyes:

    Russ
     
  15. OP
    OP
    HughJarse

    HughJarse Hardcore MB Enthusiast

    Messages:
    1,035
    Joined:
    Sep 13, 2006
    Location:
    North East
    Car:
    c250
    Lots of good answers, not sure Im any further forward. As for waiting hundreds of years....:crazy:
     
  16. Howard

    Howard MB Club Veteran

    Messages:
    18,624
    Joined:
    Apr 23, 2004
    Location:
    Toad Hall
    Car:
    CLS 500 / A 150
    The Hoover Dam had thousands of pipes inlaid into the concrete ( still there ) that water was pumped through to speed the curing process. Saw a programme on Discovery about it.

    The first concrete was placed into the dam on June 6, 1933. Since no structure of the magnitude of the Hoover Dam had been constructed, many of the procedures used in construction of the dam were untried. Since concrete heats up and contracts as it cures, uneven cooling and contraction of the concrete posed a serious problem. The Bureau of Reclamation engineers calculated that if the dam were built in a single continuous pour, the concrete would have taken 125 years to cool to ambient temperature. The resulting stresses would have caused the dam to crack and crumble. To solve this problem the dam was built in a series of interlocking trapezoidal columns. Each pour was no more than six inches deep. Because of this depth it is extremely unlikely that construction workers were accidentally buried alive in the concrete, contrary to popular folklore. To further cool the concrete each form contained cooling coils of 1 inch (25.4 mm) thin-walled steel pipe. River water was circulated through these pipes to help dissipate the heat from the curing concrete. After this, chilled water from a refrigeration plant on the lower cofferdam was circulated through the coils to further cool the concrete. After each layer had sufficiently cooled the cooling coils were cut off and pressure grouted by pneumatic grout guns. The concrete is still curing and gaining in strength as time goes on.

    There is enough concrete in the dam to pave a two-lane highway from San Francisco to New York.
     
  17. RodgerDodger

    RodgerDodger Hardcore MB Enthusiast

    Messages:
    170
    Joined:
    Jun 8, 2008
    Location:
    Scotland
    Car:
    99 - E300 TD - W210
    I presume you are interested in strenght - rather than wetness/drying-out

    Concrete goes thru several 'hydation' and curing processes

    Crushing strength increases are measured in 7, 14, and 28 day strength.

    Generally speaking it will achieve 80-90 % of its strength after 28 days - it will continue gain further srength through time - in years - its an asymtotic curve

    It actual strength will differ on the mix (a significant factor is the w/c ratio - i.e., water/cement ratio should be 0.45 for optimum strength) and is dependant on many other factors

    The Concrete mix can be 'prescribed' or 'designed' . Generally speaking- after 4-7 days reinforced concrete should have sufficient strength - for striking (removing the shutters) i.e., be strong enough to support its own mass only - for floors 'on hard' (not simply suported) you would be able to walk on the first pour (no screed) after say two days - however it is still curing and is suseptable to shrinkage therefore for example, tiling would have to wait.
     
  18. Will

    Will MB Club Veteran

    Messages:
    11,050
    Joined:
    Jan 21, 2003
    Location:
    Surrey
    Car:
    GL63 AMG / S211 E55K AMG / 190E 2.3-16 / 190E 2.5-16 / Porsche 911
    I'd wait a few weeks before tiling it. The basically-correct answer seems to be leave it as long as you can. In all seriousness, although concrete continues to 'cure' for years, I doubt you'd notice much difference from one month to the next when you're talking years...

    I know if you're laying a proper wood floor, you need to leave it several months for a floor to be thorougly stable in terms of moisture etc.

    Silly question, but who built the base and did they suggest anything?

    Will
     
  19. cidersurfer

    cidersurfer Hardcore MB Enthusiast

    Messages:
    100
    Joined:
    Oct 7, 2006
    What flooring are you putting on it? Will is right, it's the moisture content of the concrete that will be the deciding factor...
     
  20. whitenemesis

    whitenemesis MB Club Veteran

    Messages:
    15,807
    Joined:
    May 7, 2007
    Car:
    Lexus RC300h F-Sport 2019
    And so, back to post #4 :)
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.