1 Coat plastering - reasons not to?

Discussion in 'Builders' Talk' started by Paul2978, Sep 13, 2019.

  1. Paul2978

    Paul2978 New Member


    I maybe opening a can of worms here, but why do we have to do 2 coats of plaster?

    All the youtube videos show 2, but I have seen the occasional one where they only do one coat?

    As a DIY plasterer I am sure I have missed a few bits on the second coat - but I have never noticed any difference between them?

    Can I not just lay it on a little thicker and flatten it in? If I only did one coat and it looks fine is it all going to fall off in 6 months? There is a lot of information out there and a lot of opinions but in reality what can or would happen?

  2. mcooper2406

    mcooper2406 Active Member

    I'm only DIY myself but have only ever used 2 coats on old walls i.e not dot and dab walls.

    With plasterboard 1 coat is usually pretty perfect after a spot of filling and sanding back, with an older wall the first one usually looks like porridge and the second fixes it up.

    Again though, I'm just DIY.
  3. Hfs

    Hfs Active Member

    One thick coat (the same thickness as two coats) Refina spatula and a medium course sponge float.

  4. Paul2978

    Paul2978 New Member

    Yes thats what I'm thinking why do so many people do 2 coats seems so much easier to have 1 thick coat?
  5. Hfs

    Hfs Active Member

    Because that’s the traditional way to do it. The plasterer I use sponge floats and it’s immaculate...A lot of old school spreads don’t like it though, they don’t seem to have any good reasons behind it though.
  6. Wayners

    Wayners Screwfix Select

    First one can pick up grit or have varying thickness so a little uneven setting, making it hard to get good finish. The second coat beds on top a treat and gives a nice finish so is always preferred method.

    I sometimes bang on a thick first coat, then wet sponge and finish off as its quicker, but not so good as 2 coats for best finish.

    To sponge or not to sponge is another topic.
  7. CGN

    CGN Screwfix Select

    First coat roughs it out, and also helps give more even suction. Thinner 2nd coat to get the imperfections on the first.

    This is a tried and tested method. If you’re learning plastering, then stick with 2 coats and perfect the method...it works.

    One coat and spongeing is fine in certain situations, but your timing has to be spot on.
    Get the wrong timing and all you’ll do is pull all the grit in the plaster to the surface.
  8. ajohn

    ajohn Screwfix Select

    As I found via a 1 coat plasterer - to my cost. Walls were not flat and a bit wavy. Net result plaster in places way to thin so fractured and lifted as soon as a mist coat went one. There seems to be a lot about who just put the minimum on and one coat.

  9. masterdiy

    masterdiy Screwfix Select

    I have always ever done 1 coat. After that my shoulder goes & I'm knackered.
    But I'm only DIY, then wallpaper or lining paper, does a good job.
    Never ever had any plaster lift or crack.
    Wallpaper keeps it all in place. :)
  10. CGN

    CGN Screwfix Select

    There is only so much you can ‘level’ with skim. If needs be, wall can be bonded out first. 2 coat is the proper way to apply multi finish. One coating is generally only used by spreads working on new builds/plaster board.
  11. gadget man

    gadget man Screwfix Select

    One coat plaster is fine for patchwork etc
  12. Wayners

    Wayners Screwfix Select

    I use Halftime plaster accelerator added to first skim then get the second on sometimes if I need to crack on.

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