Screed cracking and sounds hollow

Discussion in 'Subfloor Preparation' started by Weronika, Aug 17, 2022.

  1. Weronika

    Weronika Member

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    We had very uneven bitumen floors which we needed levelling to put floating engineereed wood floor in.

    The guy came in filled in the cracked off bitumen near the edges, installed a DPM(tremco ES100) which was sandwitched between screed layers (tilemaster Pro flow and boostic screedmaster SLC540). He said he also used a primer at some point-looked blue not sure what brand.

    A builder neighbour said he just about managed to level his floor but the subfloor is difficult to get anything to stick-whatever that means.

    After it has been poured there was minimal traffic in the house as it's empty. A couple of days after it has been pretty hot though (35C, but at the time work was taking place it was about 20-25C)

    It's been about a week since the floor has been poured but long hairline cracks started to show. When tapped it sounds hollow around the cracks and they feel a bit raised when hand is moved over the surrounding area. Also my partner jumped in a particularly cracked spot and there was a bit of movement in the floor...

    Has the screed blown/failed?

    Is there an appropriate time to wait before laying 3k floor down to make sure the cracks won't get worse, cause massive bumps and make the floor come up?
     

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  2. HC&F

    HC&F Well-Known Member

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    Wouldn’t of personally used this materials & would of wanted those thermoplastic tiles up (if that’s what I can make out)
     
  3. Weronika

    Weronika Member

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    Yeah that's what they suggested although they were pretty solid so we said to just leave it.

    What materials would you use?
     
  4. HC&F

    HC&F Well-Known Member

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    Would have definately had them up. I would have used an ardex system over it.
     
  5. Rugmunching

    Rugmunching Well-Known Member

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    That needs taking up as it will probably get worse.

    I would have used the ardex route also, done many without fail.
    It's a shame as it looks like he done a decent finish.

    What has he said about it?
     
  6. Weronika

    Weronika Member

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    And
    We've not mentioned it yet as he took any questions we've had very personally like we don't 'trust him'. He seems old school and like a good guy but very tempremental when questioned. We'll probably mention it next week and in the meantime see if it gets worse-he is supposed to be laying our floor too in a few weeks...
     
  7. Weronika

    Weronika Member

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    So ardtex never cracks? I've read online it's pretty common for screed to crack though...
     
  8. Rugmunching

    Rugmunching Well-Known Member

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    Any screed can crack if the correct method of prep in the subfloor isn't carried out correctly before you start pouring the screed.

    ....and don't wait for it to get worse and don't consider laying on it either, it has to be removed. Before you know it your new floor will sound like you are walking on broken glass!!

    If this guy is decent then he will sort it for you, no way can he think of laying your new floor on that and be a true professional at the same time o_O
     
  9. Rugmunching

    Rugmunching Well-Known Member

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    You get hairline cracks then you get full blown cracks....2 totally different scenarios ;)
     
  10. Weronika

    Weronika Member

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    So you wouldn't consider these hairline cracks? Or you're saying it will develop into proper cracks over time?
     
  11. Rugmunching

    Rugmunching Well-Known Member

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    You saying they move up and down points to blown screed, hairline can be caused sometimes when the screed is under heat whilst drying like I had on a job once where I had hairline cracks where the sun was shining through the sky lantern. Didn't cause the screed to blow or sound hollow, just a very faint line.

    Yours is a different ball game, if you can see the floor moving up and down and it sounds hollow then the screed is clearly not connected to the floor underneath it therefore blown. I bet if you tapped a flat head screwdriver down one of the cracks and pulled down on it, you'd see it move even more and literally come up in big clean pieces.

    Your new screed has failed!
     
  12. Rugmunching

    Rugmunching Well-Known Member

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    Your new engineered wood flooring will more than float, it will bounce and crack at first till eventually it all comes loose.
     
  13. Rugmunching

    Rugmunching Well-Known Member

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    Let us know what your fitter says, best to mention it straight the way to him so he can get things in motion :cool:
     
  14. merit

    merit Well-Known Member

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    How deep was the leveller poured? Pro flow is pretty good on bad subfloors but Bostik screed is terrible. Wouldn’t trust it to bond to anything. Sounds like he’s mixed all different products too. Why didn’t he just use the tilemaster system? If it’s gone over vinyl tiles they can lift.
     
  15. Weronika

    Weronika Member

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    It will be different thicknesses in different places. I would imagine where the worst cracks are (in the corridor which was probably trafficed the most) it's not too thick as other rooms were 'lower' but im not too sure.

    I think he might have used one on the bottom and the other on top of the dpm?

    As said before hes not the easiest to communicate with.
     
  16. Weronika

    Weronika Member

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    He said : 'it's normal mate don't worry about it'
     
  17. Spacey

    Spacey Super Moderator Staff Member

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    That is normal.......When you let a builder touch a floor !!!:rolleyes:

    It was doomed to fail from the start and will only get worse not better I wouldn't lay a carpet on that never mind a 3k worth of flooring. :(
     
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  18. Rugmunching

    Rugmunching Well-Known Member

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    Holy sh*t so he's still thinking he can lay on it?? :eek:
     
  19. Weronika

    Weronika Member

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    He's not a builder hah hes a wooden floor specialist.
     
  20. Weronika

    Weronika Member

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    Yup, what can I do if he's not willing to fix it thinking it's normal/acceptable? Take him to court for a refund? We've payed him already for the screed and don't really have the money to bin him off, dig it up and start again...
     

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