Dot and dab - newbie advice please

Discussion in 'Builders' Talk' started by diymostthings, Aug 11, 2018.

  1. diymostthings

    diymostthings Well-Known Member

    Will soon be having my first go at dot and dab dry lining. To make it easy for you experts, my 4 questions have a simple Y/N answer!

    Q1: Should I/could I use quick setting cement in the mortar?
    Q2: Should I use cement plasticiser (e.g. fairy liquid)?
    Q3: Substrate is fairly uneven but sound plastered masonry (bit of paint here and there). Should I use latex PVA in the mortar mix and/or on the plastered surface (where the blobs will be, until tacky).
    Q4: Do I need to leave a small gap between the floor and the bottom edge of each board?

    Thanks in advance for any Yes/No answers (or a few more words if you have the time!)

    diymostthings
     
  2. Q1, Dot & DAB, cement in the mortar?
    Q2, No cement in board adhesive?
    Q3, Still confused.
    Q4, Yes.

    Hope it helps, been D&Bing all day....
     
  3. Magicspark

    Magicspark Active Member

  4. fillyboy

    fillyboy Well-Known Member

    1. Eh?
    2. Eh?
    3. Eh?
    4. Yes

    You don't use mortar for dry lining, use board adhesive, mix as directed, 1 bag should do 2 full size boards. Leave the fairy liquid in the kitchen.
     
    blarblarblarblar likes this.
  5. stevie22

    stevie22 Active Member

    You use drywall adhesive not cement mortar. Plenty of how to vids on you tube.

    make sure you have a good straight length of 4x2 to gently beat it into line
     
  6. diymostthings

    diymostthings Well-Known Member

    Ah - i fell at the first hurdle - I thought the "adhesive" was mortar!
     
  7. diymostthings

    diymostthings Well-Known Member

  8. diymostthings

    diymostthings Well-Known Member

    OK thank you!
     
  9. No mate, nothing like it. More like filler tbh. Sticks to everything and goes rock hard once dry, mix it by the bucket load. I tend to use 1 bag on roughly 1 and half sheets, don’t quite manage two sheets as I like to make sure it’s pretty solid.

    Good luck with.
     
  10. Magicspark

    Magicspark Active Member

    How many boards you got to stick?
     
  11. fillyboy

    fillyboy Well-Known Member

    I've never tried the foam, how do peeps find it to use compared to normal adhesive?, I would imagine it needs a gentler approach.
     
  12. sospan

    sospan Well-Known Member

    As well as big piece of timber to persuade it into place, you need a long spirit level to make sure the board is plumb (vertical)

    You will also find it quite difficult to mix in a bucket with a stick - you will need a strong drill and a paddle mixer attachment
     
  13. diymostthings

    diymostthings Well-Known Member

    Thanks - I think I need it!
     
  14. diymostthings

    diymostthings Well-Known Member

    well its not plasterboard as such - its "Jackoboard" with waterproof faces and foam interior. its for a shower room with three external walls (so I needed the insulation core). But the instructions say "dot and dab" in place. Which is why I asked the questions. Thanks for your reply. Much appreciated.
     
  15. diymostthings

    diymostthings Well-Known Member

    I have got a paddle mixer for my Dewalt drill and have used this successfully to mix up "multi". Thanks for the tips.
     
  16. sospan

    sospan Well-Known Member

    Jackoboard normally requires a rapid setting single part flexible (SPF) cement tile adhesive, which again is different from dot and dab adhesive. I would also add fix into the wall with good quality wall plugs and screws.
     
  17. diymostthings

    diymostthings Well-Known Member

    Thanks for that- yes I have some of the special plastic "washers" for screw fixing and will now look into that SPF adhesive.
     
  18. chippie244

    chippie244 Well-Known Member

    Pink foam is excellent.
     
  19. diymostthings

    diymostthings Well-Known Member

    Do you mean the polyurethane foam which expands on application? I can't see how I could get the boards flat and in line if the adhesive is expanding...?

    Thanks Chippie
     
  20. Magicspark

    Magicspark Active Member

    He means the same thing I linked to earlier.
     

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