hopefully a quick and easy question regarding liquid DPM

Discussion in 'Builders' Talk' started by deanomc, Dec 9, 2016.

  1. deanomc

    deanomc Member

    Does my concrete floor also need liquid damp proof membrane adding before adding a self leveling compound if the floor already has a DPM sheet underneath it. Its a 75mm thick concrete that has been allowed to dry over 4 months.
     
  2. KIAB

    KIAB Super Member

    No, but I would use a primer on the floor before using leveling compound.
     
    deanomc likes this.
  3. deanomc

    deanomc Member

    Thanks KIAB. I was reading the manufacturer instructions on the leveling compound and it mentioned addind a Liquid Damp Proof so just I just wanted to make sure. It must have been referring to slab laid on top of soil without a sheet. Cheers.
     
  4. KIAB

    KIAB Super Member

    But, I can see the sense of the manufacturer instructions recommending a liquid dpm,it does gives you a second level of defence, if your dpm,unknowingly got punctured during installation, or the floor is old & there a risk or signs of old dpm failing, or your unsure there is one present.
     
  5. deanomc

    deanomc Member

    If I was being double sure..........Liquid DPM, then prime, then self leveling?
     
  6. sospan

    sospan Screwfix Select

    Unless you specifically need it, I would leave off the DPM. Some DPM products have aren't the best things to stick to even with a primer as they have some flex in the product and can have a greasy feel to them. Floor leveling compound can become flaky in places where it fails to adhere to floor surfaces.

    I had to fix leveling compound where it has failed to adhere in places and gone flaky and it is a real pain to put right, so I try and keep as few things to go wrong as possible.

    Where people have been walking over the floor, give it a quick rub over with a sander or angle grinder just to scuff up any ingrained dirt and grease
     
    deanomc likes this.
  7. deanomc

    deanomc Member

    I already have the liquid DPM so it wont cost me any more to do so
    I've been using Black Jack liquid DPM and have noticed it is in fact has a greasy finish. I'm going to take your advice on this on 'sospan' and keep it simple. Clean, prime then self level,

    Thanks as always
     

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