Repairing external render

11 Jun 2009
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United Kingdom
Hi there

My house is brick-built, with a layer of external cement render covering the bricks up to a depth of about an inch.

During recent bathroom works I've had to push some now-defunct pipes out through the external wall. This has pulled off the external render, which I want to repair.

From what I've been told the render mix should be 1 part portland cement to 5 parts sharp sand. Is this correct, because there is some contradictory information out there about render mixes...

Any replies much appreciated
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I would make sure the hole is dust free and wet it down, give it coat of 4:1 , filling it out to maybe 6-8 mm behind your finished surface, and scrathed.. Then after at least a day , a 5:1 mix filled out and finished wiil be fine. A fine sharp sand(3mm down) will be better than sharp , but if they are only small holes, any sand should be okay if you can blend it in
The hole in the brickwork is about 3cm diameter, with the hole in the render spreading out to about 80mm on the outside wall.

As an alternative, would some ready-mixed mortar do the trick? Wickes do a 'mix and go mortar repair' bag that looks just the ticket if it's appropriate.
I can't add anything else to what Micilin has recommended.
"Mix and Go Mortar Repair" from Wickes ?? no thanks,, not for me. I would sooner mix my own. I'm sure you can get 2 or 3 shovels of fine plastering sand and drop of cement from a local builder/friend,, for all you'll need,,, just add a "little drop" of plasticiser to the mixing water,,,, Fairy Liquid!!!! who said that??? :LOL: Don't make the mix too wet though, and as Micilin said, fill the hole out three quarters on one day, scratch it,, and bring it out flush the day after,, blending in the edge of the patch, neat and flush with the original render. Give it a light rub over with a piece of sponge when it's ready,, and that's it.

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I'm a bit confused now... If I get a bag of 'plastering sand' is that a fine sharp sand then? Or would I be using sharp sand for the 4:1 and the plastering sand for the 5:1?

Sorry, I've never mixed my own cement/mortar/render before...

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