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Rendering Breeze Block Retaining Wall

Discussion in 'Building' started by humble_beginnings, 14 Jul 2006.

This topic originated from the How to page called Rendering.

  1. humble_beginnings

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    Hi,

    I have constructed a rather sizeable retaining wall out of the 4" high-density breeze blocks one can buy. I have also built 2 flower beds and a garden wall out of said blocks.

    With regards to the retaining wall and flower beds, is there any point in rendering them - I am worried about moisture blowing off the render come the frosts... I have the option of putting a PVC membrane behind the walls for the flower beds, but not the retaining wall.

    What would be the best way to render the garden wall - mixtures, techniques etc?

    Cheers

    Tim
     
  2. Static

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    Is why you dont build retaining walls out of blockwork. Its too light and susceptible to frost. How much soil is it retaining? and have you backfilled behind it yet?
     
  3. humble_beginnings

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    Is a fair bit of earth to be fair. It appears to be solid for the moment, so that's good :) The blocks I have used are far from "light" though, or do you mean something else by that?

    I will elaborate. I have a long garden which has a bit of a gradient on it. It already had 2 terraces on it, but there was still a section that sloped heavily. I decided to terrace this bit also. I built a wall and anchored it at either end, with one end having steps built into it. Infront of the wall are the remaining steps down to the level below and one of the flower beds. All in all, I would say the top of the wall is about 4' higher than the top of the flower bed. Behind the wall is mainly clay with about a 12-18" of top soil.

    Is that enough of a description?
     
  4. Static

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    Depends on the type of block i suppose.. a normal "standard" block is about 1/3rd the density of a brick thus 1/3rd the weight. Only high density blocks come close to brickwork on weight.
    4' tall built in masonry is quite large, i hope you increased the thickness of the wall close to the base and put in a fair size footing.

    Youve pretty much 2 options on damp proofing.. either you let water leach through the wall or you put a membrane/tanking layer behind the wall. Leached water will bring a residue with it that will stain the wall over time. Weepholes/drainage at rear of the wall can help slow this.
     
  5. noseall

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    did you use high density 7 newton concrete blocks?
     
  6. humble_beginnings

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    Thanks for the replies. I did use the high density blocks yes and bloody heavy they are too! Def not the lighter ones...

    WRT to rendering then... Given my situation what do people advise? I don't think the standalone wall will give too much trouble, but what mix to use and how to apply? I am most concerned aboutt he retaining wall tho - is it worth even attempting to slap a render on? If so - how would be best to attack this?

    Cheers

    Tim
     
  7. andytheotter

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    I'm new here...but what else are you likely to build your retaining wall out of?!?
    As for the concrete breeze blocks they're fine for retaining...if using 4" jobbies they should be laid block on flat...6" blocks are fine upright.
    Render mixes, down here we use holm sand with normal cement in about a 5:1 ration...a scratch coat first then a finish top coat. Don't forget to use some sbr or plasticiser.
    Hope this is of some help.
    Andy.
     

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