Mortar and render not adhering to external brick wall

I have low garden wall which has been painted over the years. I used a wire brush and PVA on the surface prior to adding a mortar . The end product was that it was very bumpy. The next day I brushed down the wall and hosed it down before adding the render which was 4 parts sharp sand and 1 part cement and 1 part lime. The result was that it did not stick and fell off. Can someone advise where I went wrong .

10 Answers

First of all using sharp sand is not good for the cement to bond as it does not spread as good as building sand. And the walls require r.s.b blue gritt as it has a stronger pva mix to stop moisture and loose mortar from coming through.
20th Sep 2018
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Mix should be gauged 3parts building sand 1part sharp 1part cement and surface should be dust free and pva applied before scratch coat
21st Sep 2018
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either garden wall to dirty for second coat or to much water in in retaining wall or possible to much feb/waterproofer in first mix.hope that helps a little.
20th Sep 2018
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Daniel Soos
11 Reviews, 100% Positive
Good afternoon
Please post the job on website and attach photo
Someone will be able to do the job right.
Also need to see it before.
Thank you
Daniel
18th Oct 2018
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SPF LINCOLN LTD
3 Reviews, 100% Positive
Did you use some sbr in your mix it helps the mix to go fluffy. If I was you I would put a thin coat on first and then scratch it then put your second coat on after.
9th Oct 2018
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Beenrecommended
31 Reviews, 100% Positive
dont use pva use a morter adhesive and you should be fine
24th Oct 2018
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Harpersandsons
5 Reviews, 80% Positive
I think it was still wet and Maybe another coat of pva on top of your first coat
29th Oct 2018
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oakham plastering & property care
1 Reviews, 100% Positive
The render will not stick to painted brick work try getting all the paint off rake all the joints back to get a good key then 3/1/1 mix and top with a 5/1/1 mix.
8th Nov 2018
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Pm plasterers
1 Reviews, 100% Positive
First off you went wrong with using sharp sand for rending also using sand and cement over paint work it doesnt stick and just becomes blown render the best way to tackle something like is give it a key if its solid or if blown take the blown render off if not use a splits mix which is 1 soft wash sand and 1 cement paste it on and gives it a good solid key to render over the top
22nd Nov 2018
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Try a sbr stabiliser this will seal any dust damp etc and will act like a pva adhesives.
30th Nov 2018
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