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External render mix

Discussion in 'Plastering and Rendering' started by johnscts, 13 Sep 2020.

  1. johnscts

    johnscts

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    I have previously asked about the mix required, I have only about 3 metre of rendering to complete (picture to show how much of an area) I have purchased 1 mtr of Bellcast beading In preparation. I have the following materials
    I have bag of Sharp sand, bag of builders sand, SBR liquid, Waterproofer, and cement.
    What is the mix ratio:
    1: Can I mix sharp sand with builders sand ( ratio if I go that way)
    I have taken off as much of the previous cement. So am going to put a final coat on.
    2: I had a plasterer in last year to do one side; but he has gone into retirement and left the area. So I am on my Jack no, and try and blend in the remaining side. To show the area I will
    again attach a pic 5F73F957-48FD-4254-9C2A-4ED2751AD5EA.jpeg
     
  2. bennymultifinish

    bennymultifinish

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    the previous reply i gave still stands.
    you don’t need the bellcast bead and you can’t mix sharp and building sand in the same mix for rendering.
     
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  4. johnscts

    johnscts

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    Yes I remember I get so many different answers. So I suppose it has to be 6 plaster sand and 1 cement - with nothing else ( by that I mean waterproof or SBR). This is the final coat
     
  5. bennymultifinish

    bennymultifinish

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    you intend plastering it flat?
    if so the surface looks as if the finish will be proud of the dash. also your scratch coat wont provide adequate key.
    this isn’t good and will transport rainwater into the wall.
    ideally you need to remove the scratch coat too and redo the section in one coat, so the finish level is not proud of the dash.
    builders sand with a ratio of 4 1/2 sand 1 cement and 1/2 lime.
    or 4 1/2 sand 1 cement and waterproofer in the mix.
    6:1 is too weak imo.
    5:1 would do.
     
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  7. johnscts

    johnscts

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    Thank you that is what I will do. I think I have not been very clear; I have been asking questions on the conservatory brick work (plaster mix and the amount of mix ) then finishing with a finishing plaster.

    And then the outside render mixes ( the confusion for me on the outside was > what sand and I am happy to go for the 4 and a half mix with splash of waterproof.

    kind regards. John
     
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