laybond rapid DPM

Discussion in 'Subfloor Preparation' started by doidgey, Mar 14, 2012.

  1. doidgey

    doidgey Well-Known Member

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    Been using this to day did as read on the label one coat wait 30 min till dry then another coat rolling the opposite way wait 1 hour till dry prime and then screed as i was screeding it kept pulling off the floor in small bits stuck to my boots and knees, its crap have you used it anybody.

    Steve.
     
  2. dazlight

    dazlight Super Moderator

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    I've used it on quite a few jobs mate and like it.
    I was told by the laybond rep not to prime it though if your screeding it same day.
    So I do 1st coat 20 min wait
    2nd coat wait a hour
    Then screed.
    Found it works mate as not had a call back. I've done about 5 jobs with it.
    I hate the Screedmaster trade though as had 10 bags of that. Never using it again.
     
  3. Matt

    Matt Well-Known Member Staff Member

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    nice.

    what state is the subfloor in ? is it very dusty?


    have you used Mapei 1k turbo? if so would you think you would have had the same issue?
     
  4. doidgey

    doidgey Well-Known Member

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    No Matt not dusty never used 1k turbo, as daz says don't prime but why on the tub it says prime before screeding which does make it a bit tacky.

    Steve
     
  5. doidgey

    doidgey Well-Known Member

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    Thats the screed iv been using its what the shop give me and is crap dry's a bit dusty so i prime it after, wish id know about not priming the dpm.

    Steve
     
  6. Matt

    Matt Well-Known Member Staff Member

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    just to note,

    The lack of primer. Your sticking screed to a impervious material (the dpm)

    They may say you dont need to prime if you install withing 12 hours etc maybe? if it goes longer then you need to prime.

    So bare in mind the above, lets say it does go wrong and they ask where is the proof of primer. Well there is no primer as you laid on it as instructed within the time period. PROVE IT !

    Lot of fitters coming into trouble with these 'no need to prime' systems. Cant name any names as a court case etc going on, but this is a regular thing we see.
     
  7. Robroy

    Robroy Well-Known Member

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    Is this the dpm which they say can used over a floor with no phisical dpm ?
     
  8. dazlight

    dazlight Super Moderator

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    No mate it's not.
    This can only be used on a floor with a existing dpm.
    If no dpm and not sky high damp reading then I do below , but it's not guaranteed.
    If using laybond -
    If bit of old adhesive down or rough floor, screed with ultimate , no primer.
    Then 2 coats of one coat membrane
    Prime & screed.
     
  9. Robroy

    Robroy Well-Known Member

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    Will check but one of my suppliers are advertising this wrongly then !
     
  10. Matt

    Matt Well-Known Member Staff Member

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    Trust me, there is not a surface dpm out there than can go over a floor with rising damp. You maybe lucky and get away with it. The water table for the house will make a big difference on if it will go wrong or not.


    Tell a lie, there is surface dpm systems like asphalt that can be used. But this uses its own weight to hold it self down. A painted on product has no weight behind it.
     
  11. tarkett85

    tarkett85 Well-Known Member

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    or use Uzins NC 194 Turbo, sets quickly and built in DPM. ;) then prime and use NC 174 or NC 145 over the top.
     
  12. Robroy

    Robroy Well-Known Member

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    Yes I remember what you told me on the course , so I was suprised when I saw them advertising it as such
     
  13. Matt

    Matt Well-Known Member Staff Member

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    if you use the product and it blows off the floor it will normally pull a fine layer of the subfloor up with it. So it is actually the subfloor that fails and not the DPM. So that is why some say you can do it. Its the subfloor that fails and not there product.

    Most manufactures save you the hassle by simply telling you not to use it as they know there will be issues.
     
  14. Matt

    Matt Well-Known Member Staff Member

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    Do they say that can be used over rising damp ? At what thickness? 25mm + if bonded maybe?
     
  15. tarkett85

    tarkett85 Well-Known Member

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    Either bond with a slurry wet on wet 25mm thick screed, or use sheet dpm with 35mm thick screed.
     
  16. Matt

    Matt Well-Known Member Staff Member

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    top of my head i thought minimum unbonded (onto sheet) was 55 mm? cant remember so will look it up.
     
  17. tarkett85

    tarkett85 Well-Known Member

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    Do they say that can be used over rising damp ? At what thickness? 25mm + if bonded maybe?[/quote]

    Either bond with a slurry wet on wet 25mm thick screed, or use sheet dpm with 35mm thick screed.[/quote]


    top of my head i thought minimum unbonded (onto sheet) was 55 mm? cant remember so will look it up.[/quote]

    35mm is what the tech PDF says, but i'm with you on doing 55mm
     
  18. Matt

    Matt Well-Known Member Staff Member

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    do you have the PDF mate? what product are you talking about?

    just so i know we are talking about the same thing here !
     
  19. tarkett85

    tarkett85 Well-Known Member

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    i meant NC 190 http://www.uzin.co.uk/uploads/tx_dddownloadmatrix/6574_01.pdf
     

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