Screed help

Discussion in 'Vinyl / Impervious floor coverings' started by Brady2, Aug 5, 2021.

  1. Brady2

    Brady2 Member

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    Hi all,
    After recently re-roofing our garage (and having to demolish one wall and relay foundation) we decided to get the floor levelled to tidy it up.

    The builders measured and noted a 4cm drop in one corner.
    They recommended 80 bags of cempolay ultra strong to make it level. Garage is 7.5m by 3.5m

    We agreed on 40 as it was a tidy up, didn't need to be perfect.

    The builders mixed the first 30 bags as per manu instructions of 1 bag to 5 litres of water and the last 10 bags they did 1.5 bags to 10 litres...

    Because of the dip in the floor it went in a bit thicker in places. Possibly UpTo 25-30mm.

    The screed is still wet after nearly a week and this stuff is meant to set with a few hours.

    Will this screed eventually dry?
    There's the odd hairline crack and bit of powder but final finish is rubber based tiles so not too bothered as long as it can take a very heavy car...

    Is this drying time ok?
     
  2. Rugmunching

    Rugmunching Well-Known Member

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    Dry time a few hrs yes if at a standard coat ie.3-4mm but the deeper you lay it then it will take longer to dry out. Anything over 20mm with that stuff is supposed to be mixed/supported with extra sand or fine gravel.

    Did your builder not mix it with anything to bulk it up for the deeper section?

    Is the while screed slow to dry or just the deeper section?

    Supposed to if its over 20mm really and temperature has a lot to do with dry times as well.
     
  3. Rugmunching

    Rugmunching Well-Known Member

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    *whole screed
     
  4. Brady2

    Brady2 Member

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    He didn't mix it with anything.
    It's set where it either wasn't as thick or where it didn't need to run to level. The more watery last few mixes are what's still like clay/putty.

    Aslong as it'll eventually set hard enough I'm all good.. not worried about the finish and the concrete underneath is about a meter thick across the whole slab...
     
  5. Rugmunching

    Rugmunching Well-Known Member

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    Too much water
     
  6. merit

    merit Well-Known Member

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    Too much water


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  7. merit

    merit Well-Known Member

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    You could try to force dry it with heaters. It will always be weak now tho. Could also crack more


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  8. Brady2

    Brady2 Member

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    When you say weak.. it'll crack when driven on?
    Is there anything that can be done rather than pulling it all up? I.e. can we put more ultrastrong Cempolay no top?

    The plan is to have the floor covered with PVC or Rubber mat, so appearance of the screed isn't a concern.
     
  9. Rugmunching

    Rugmunching Well-Known Member

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    I'd say it'll sink in the soft areas and the rest will crack of its been over watered...

    No good putting another coat over it. The floor will be as strong as what's supporting it.....and by sounds of it putty won't hold it

    Appearance isn't the issue we talking about, it's the strength you need
     
  10. Rugmunching

    Rugmunching Well-Known Member

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  11. Jason Sheehan

    Jason Sheehan Well-Known Member

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    Another customer successfully depressed LOL
     
  12. Rugmunching

    Rugmunching Well-Known Member

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    I blame these tradesmen and their horses :D
     
  13. merit

    merit Well-Known Member

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    All I hear is depressed customers. They want a quick, cheap job what will last a long time. Doesn’t exist


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  14. Brady2

    Brady2 Member

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    Hey hey, this was by no means a cheap job. We paid nearly £2k just to lay the self levelling screed.
    The builders were in and out in less than half a day.

    I've no problem paying for quality work, but your replies and what I can see in the garage makes me think this isn't quality work. We seem to have a lack of good trades people around here, regardless of the price paid.
     
  15. Rugmunching

    Rugmunching Well-Known Member

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    Should have been bulked up really.

    How is it now? Has it got worse?
    Still soft in places?
     
  16. tarkett85

    tarkett85 Well-Known Member

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    I just checked the screed it’s not suitable for use in a garage, you need a minimum compressive strength of 28n/mm2 after 28 days Cempolay is only 20n/mm2 after 28 days sorry for the bad news you shouldn’t park anything on it.


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  17. tarkett85

    tarkett85 Well-Known Member

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    And I hope they did a Rh% reading because it’s not moisture tolerant.


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  18. Jason Sheehan

    Jason Sheehan Well-Known Member

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    Brady2.. this is very good news. The latex is not fit for use and also seems to done wrong also.. you should seek full refund plus cost of removing their poor work also. You'll need a report if they refuse and has to goto small claims court.
     
  19. merit

    merit Well-Known Member

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    Sorry. That comment wasn’t aimed at you personally. Just commenting on my own experiences


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  20. LKAB Gypsol Alan Jackson

    LKAB Gypsol Alan Jackson Well-Known Member

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    Sorry to butt in but that's incorrect. The minimum strength for a concrete to be used in a domestic garage in the UK is a Gen3 concrete. This offers a minimum characteristic strength of C20/16 so a typical strength of C20 or 20N/mm2 and a cylinder strength if 16n/mm2

    Note: A standard land rover defender offers a loading of just 0.26n/mm2 per wheel (equivalent to 38psi tyre pressures). Weighing 2.4 tonnes if you jacked it up on four Jack'sone at each corner, each Jack would put down approx 6.6N/mm2
     

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