quarry tile floor with no phisical dpm

Discussion in 'Subfloor Preparation' started by Robroy, Sep 6, 2012.

  1. Robroy

    Robroy Well-Known Member

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    Got a quarry tile floor in an old cottage, where about a year ago I screeded and laid a vinyl which has bubbled :oops:
    ( screed was fine Latexplan trade)
    I have put my meter on it and its reading 96 rh, I was told by the laybond rep to scrape up existing screed, put double the amount of their one coat on the quarryies then re prime and re latex afterwards.
    whats the chance on this being successful bearing in mind there wouldnt be a phisical dpm under the concrete??
    The estate I do jobs for own stacks of cottages, over a year we might have one vinyl that fails due to moisture, its always a sheet vinyl thats fitted.
     
  2. dazlight

    dazlight Super Moderator

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    Do that with ardex NA mate and dpm 1c. Only dpm that has a guarantee over floors with no dpm under the sub floor. The ardex rep said that on sunday to the nicf.
     
  3. Robroy

    Robroy Well-Known Member

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    This laybond stuff does say you can use it over no phisical dpm, but I know what Matt will say !
     
  4. merit

    merit Well-Known Member

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    If the screeds ok can you use an isolator sheet?
     
  5. Matt

    Matt Well-Known Member Staff Member

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    yes you can
     
  6. dazlight

    dazlight Super Moderator

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    Really they should be dug up but if not then go for a surface dpm.
    Had a laybond one fail on me. Will be posting pictures in a month.
     
  7. Matt

    Matt Well-Known Member Staff Member

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    When i questioned the ardex rep about the quote with the question - "if your dpm comes up but has a thin layer of the subfloor attached to it, well is that guaranteed? "

    ANSWER- "No, the subfloor has failed"



    DPM's dont fail. The subfloor they attached to does.
     
  8. dazlight

    dazlight Super Moderator

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    So the dpm has worked then
     
  9. Matt

    Matt Well-Known Member Staff Member

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    Epoxy DPM itself (the actual product epoxy) wont fail once set.

    What the DPM is attached to can fail. As you are always relying on the subfloor surface strength you are always at risk if there is no sheet DPM under the floor as it will be under pressure.

    Hence we always say DONT apply a surface dpm to a subfloor subject to rising damp.
     
  10. Robroy

    Robroy Well-Known Member

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    Tell me more ?
     
  11. Matt

    Matt Well-Known Member Staff Member

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  12. dazlight

    dazlight Super Moderator

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    It's a gamble Matt but as you said before its all about the water table.
    I check the water table now before I do it. But had no problems using f.ball F75 or ardex dpm1c.
    If you get me some mapei epoxy I will try that mate
     
  13. merit

    merit Well-Known Member

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    I had a similar job, another firm put down vinyl twice because of bubbling and charged for Dpm the second time but used latex. When I lifted the vinyl the screed was sound so I put down a isolator sheet and put new vinyl down. Been fine 6 months
     
  14. bournemouth

    bournemouth Super Moderator

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    Remember to wear long sleeves and gloves the bastard stuff itches like hell and lay at 45 degrees to sheet if you have joins
     
  15. merit

    merit Well-Known Member

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    That's what I used, good stuff and really easy to fit. Just make sure you order the tape as well cos they won't send it out with the sheet otherwise :/
     
  16. bournemouth

    bournemouth Super Moderator

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    Whats the mapei tape like does it show through the vinyl like others do
     
  17. Matt

    Matt Well-Known Member Staff Member

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    yep, its a gamble. I have done loads in the past without issues. I also see many failed floors as well.

    The mapei stuff is no different to others. A epoxy is a epoxy. Well i say that but mapei is slightly different. It has less fillers in it so tends to sink in a little deeper. Dought you would notice any difference between mapei and fballs.
     
  18. Robroy

    Robroy Well-Known Member

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  19. Matt

    Matt Well-Known Member Staff Member

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    i dont actually think mapei have a tape?
     
  20. Matt

    Matt Well-Known Member Staff Member

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    yes mate.

    It has its down sides tho. It dont cope well with point loading. So stuff like bar stools with small feet and it dont like 'heavy' wheeled traffic (shouldnt be a issue in domestic)
     

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