Render mix

Discussion in 'Builders' Talk' started by pete12, Jan 26, 2006.

  1. pete12

    pete12 New Member

    Is there any reason why I should NOT put Lime into a render mix that contains a Waterproofing/plasticiser additive?
    Any advise appreciated.
     
  2. nicknuv

    nicknuv New Member

    Basically, lime is a time served plasticiser but has been largely replaced by modern additives and admixture particularly the liquid form. Although the mortar is very workable, lime leaves a particularly porous finish and is not recommended for use in exposed renders. The modern plasticisers are are entraining agents which causes the formation of millions of tiny bubbles that act as shock absorbers to the aggregate causing a more 'plastic' mix, hence the regulation washing up liquid when brickies do privates. The difference is, the chemical caused bubbles dont evaporate upon curing and therefore leave the face sealed and weathertight. Lime does the opposite.

    And remember, a waterproofer acts as a plasticiser, but a plasticiser does not act as a waterproofer; and washing-up liquid was designed specifically for washing up.

    Nuv
     
  3. slapiton

    slapiton New Member

    for a half bag mix in a small mixer add one cup full of waterproof and one cupful of placticiser to a bucket of water.put your water in the mixer and then add a shovel of lime ,let it mix up for a minute and add 6 shovels of sand, half a bag of extra special cement and another 6 shovels of sand. you will then have a render mix that is workable and can breath when cured. use washing up liquid to clean the cups.
     
  4. nicknuv

    nicknuv New Member

    Slap, you a Delia Smith fan..lol?
     
  5. nearnwales

    nearnwales Member

    I always put lime in render ! more so in when am pebble dashing black and white makes the backing more lighter. Am from north wales but in cardiff where am living now they use just sand and cement and plastersizer in the scratch coat and in the top coat sand cement and lime with water proofer 4 -1 -1 .
     
  6. slapiton

    slapiton New Member

    nick have you actualy done any rendering ?
     
  7. nicknuv

    nicknuv New Member

    Done plenty mate...have you?
     
  8. If you actually had nicknuv then you would know the blooody difference between a mix with and without lime in it and would not need to try and impress with some garbled theoretical clap trap lifted from a DIY weekly publication.
    Yes put lime in.
     
  9. nicknuv

    nicknuv New Member

    Robbo, I've never read a DIY mag in my life mate. You obviously have, given you know the content.

    I'm fully aware of the benefits of lime..but to use lime, plasticiser and waterproofer together...hmmm...nice one...let's chuck in some retarder and some frostproofer too...oh...and some dye...yes, yes. oohh yes.

    Lime shouldn't be used for exposed areas...I never said don't use the two, but I do believe it's unecessary..and a waterproofer acts as a plasticiser. But, theory or otherwise, you've made up your mind. Never saw your answer to the question come to think of it...;-)
     
  10. nicknuv

    nicknuv New Member

    Pete, have a look at this description from a plasticiser tech sheet:

    'Mortar admix (25ltr) is an air entraining plasticiser that <u>replaces lime</u> in the mix to provide an easy to work "butter like" consistency to the mortar and prevent shrinking, cracking during the setting process. For use in brick laying and plastering mortars. Provides a degree of frost resistance and long term resistance to freeze-thaw cycles when set.'

    More claptrap I'm afraid, but Robbo's 'Yes put lime in' instruction will be a waste of time.

    All the best

    Nick
     
  11. nearnwales

    nearnwales Member

    but we also put lime in the mix to help with the suction for the next coat not just for the "butter like" consistency. We don't put it in just for the hell of it !
     
  12. layiton

    layiton New Member

    use lime if ya gonna tyrolean after rendering, as said above it helps with the suction!
     
  13. **** if you quote the complexeties of chemical attributes and processes then it helps to actually understand in some fashion what you copy word for word. considering you are struggling to comprehend the full detail of a most simple thread from the original poster then could you kindly explain in concise and lucid terms why where I live (Eire)it is obligatory to add hydrated lime to an external render gauge. Considering that almost universally, within 80 to 90,000 new builds per annum, the external covering is a rendered/dashed/harled/napped finish, which contains a lime additive as a matter of course through specification, this clearly makes you wrong. On the other hand perhaps a whole country, and hundreds of thousands of homes, with a climate that explicitly meets the conditions that you expressly assert "lime " should not be employed within are completely inaccurate.........Hmmmm I wonder who is wrong?
    Dont try and outsmart me, its not possible. Though it would be amusing to humilliate you further should you wish to endeavour.

    [Edited by: forum admin]
     
  14. nicknuv

    nicknuv New Member

    Wow, two replies the same...and I'm half witted...

    I wasn't talking about complexities of chemical blah, blah, blah. This is England, and lime and plasticiser together are superfluous; hence, plasticisers replace lime...personally, I prefer lime...but then I'm a half wit.

    Now, no need for insults is there?

    All the best,

    Nickpuff...x
     
  15. nearnwales

    nearnwales Member

    lime isn't used as a plastics now days its use for suction and to make the backing coat lighter . we have liquid plastics now.
     
  16. Hoskie

    Hoskie New Member

    Come on boys lets get it on!!! You cant beat a good old cyber fight ding ding round two
     
  17. nearnwales

    nearnwales Member

    meant to say plasteriser :]
     
  18. nicknuv

    nicknuv New Member

    NNW, that's my point, lime, plasticiser and waterproofer...too much going on, objectives defeated etc. I know, throw in a few bricks and dispense with the bricklayer...bit of latex and they'll lay themselves...self levelling, plasticising, waterproofing, bricklaying compound...saves hundreds on bricklayers...

    As for Robbie, I must admit, he's twice as intelligent as anyone else...he can even write the same post, word-for-word twice...and - get this - post them both. The sausage...

    He even knows what's contained in DIY magazines...

    And I'm illiterate...someone wrote this for me...

    Trdffyhrl annd therre plastizzzr...

    That was the real Nick

    [Edited by: forum admin]
     
  19. pete12

    pete12 New Member

    Just want to say "thank you" to one and all for the time and trouble you have taken to answer my query. I am sorry it has turned out to be somewhat contentious.
     
  20. mudhut

    mudhut New Member

    pete, there`s you starting a fight over render mixes, troublemaker!! this forum is usually streamlined concensus and mutual respect, `till someone comes round asking questions `bout contentious issues.....splitter!

    but seriously, try asking which way round your plasterboard should go, then you`ll see the sparks fly.

    i think the strict answer to your original post must be no, there is no reason why lime should not be added. i personally did 25 sqm of render onto flaky brickwork last summer. before starting i sought the advice of posters here and got all the answers i wanted, mainly from robbo who demonstrated a thorough knowledge of the task. the render is still up and looks fab, so i can vouch for robbo`s knowledge here. and i found that the mix with lime was even easier to finish than the scratch coat i did with opc/sand/plasticiser, and yes i measured the plasticiser which was specifically supplied for rendering.
     

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