Covering pebble dashing

Discussion in 'Builders' Talk' started by Tinderstick, Apr 21, 2006.

  1. Tinderstick

    Tinderstick New Member

    Can anybody recommend the best way to cover external pebble-dashed walls - altho' its more like grit-dashed with pieces of small sharp stone... looks c**p anyway!

    Hopefully, I'd like a smooth finish which I can then paint white. Can I just use standard undercoat and finishing plasters over the existing grit finish, or do I need something specifically for external use?

    And... would a coat of PVA on the grit help?

    Thanks guys!
  2. xr3i_alloys

    xr3i_alloys New Member

    You either need to knock it all off and render the wall or render over the dash to get a smooth finish

    Render with sand and cement or another external product not plaster

    Depending which method you choose you will need to PVA before application
  3. dj.

    dj. New Member

    don't put pva on it before rendering, it is not suitable for external use. only a dim dipshiyte would coat it with pva before rendering.
  4. xr3i_alloys

    xr3i_alloys New Member

    Are you joking

    If you have ever had problems putting PVA on an external wall then i'd say the problem lies with you and not with the PVA
  5. dj.

    dj. New Member

    like i said, a total dipshyte
  6. xr3i_alloys

    xr3i_alloys New Member

    Get off your band wagon and accept PVA does the job and like i said it's your poor skills if your work failed not the PVA which is being used for the job it is designated and has been used for decades
  7. dj.

    dj. New Member

    my work hasn't failed because i don't use pva dipshiyte.
    pva is a water based substrate and when in contact with water it "comes back" which can cause an outside application to fail, hence, don't use it outside it isn't needed.
    get back in your xr3 pikey and f uck off.
  8. vipa2000

    vipa2000 New Member

    I think tinderstick is looking for a constructive answer. I have never seen a forum like this for people been aggressive. Some people make what they believe at the time to be a good answer. If there is a better way to do it then put it across in a constructive a manner. Between you two you look like you might have the answer, but what about the spec for the sand and cement render?

    regards vipa
  9. dj.

    dj. New Member

    you are right vipa, i shouldn't rise to the bad advice i see here.
  10. vipa2000

    vipa2000 New Member

    No problem. Is it worth putting a plasticiser in to aid application. Also is there anything you could do enhance waterproofing. I have bought a farm house, actually i think it was a pig sty! I have a rendered gable end and i think i have soft spots that could do with replacing.
  11. dj.

    dj. New Member

    vipa, in your application you should always be using plasticiser anyway. scratch coat then your top coat add your waterproofer.
  12. vipa2000

    vipa2000 New Member

    Thanks for that, I am assuming a 4-1 mix? Tinderstick, if you get it wrong after this then you will be in trouble!
  13. dj.

    dj. New Member

    i would do 5:1 scratch coat and 6:1 top coat, just make sure your top is slightly weaker than your scratch coat.
  14. vipa2000

    vipa2000 New Member

    Of course hadn't thought of that. Obvious when you think about it. Just like light weight blocks and people making the mix too strong.

    Do you know anything about pointing? If so i will start a new thread.
  15. dj.

    dj. New Member

  16. NEVER use pva externally. This one has been done to death but dj as allways is spot on. Without reiterating what has been said many times over, simply look at the back of a tub of pva and you will see that it says "Not suitable for external applications" on most, or certainly on any manufacturers web sites.
  17. Tinderstick

    Tinderstick New Member

    Right I think I got the best bits out of that...

    I'm not plastering at all - nor using PVA!

    Sand and cement at 5:1 scratch coat followed by a 6:1 top coat.

    Then I can get an external paint straight on that???
  18. xr3i_alloys

    xr3i_alloys New Member

    You show me a website that says don't use PVA because i can't find one, infact don't bother, continue in your little bubble world where everything you think is right is right.

    Pointing if you are pointing brick 2 silver - 2 building - 1 cement if the mix is too claggy add more building sand ratio to silver.

    render - add a shovel of hydrated lime with your 5:1/6:1 top coat and get it even and you wont have to paint the wall afterwards it will set white plus for the time of year it will speed up setting time

    dj SHOCKINGLY i don't have an xr3 sorry to disappoint you as you are knocking one out looking at the screwfix catalogue
  19. Bob Property

    Bob Property New Member

  20. yorkshireboy

    yorkshireboy Member

    Don't listen to the scaremongers xr3i
    The likes of Robbo and dj. spend a lot of time worrying about what could happen in a worst case scenario which they have probably read on a website/back of a tub.
    I very much doubt wether dj has seen a render fail because it had pva under it
    To say it is water based so it will fail is missleading,exterior masonry paint is water based,roof sealing emulsion is water based etc etc.
    I have seen the manufacturers reccomend pva as a render admixture before
    The pva is not reccomended for outdoor use as it can degrade if subject to constant wetting
    These conditions DO NOT occur under two coats of render,if they did the render would fail anyway
    Is it possible that xr3i touched a raw nerve.You bodged a render or dashing job and blamed it on pva ;)

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice