Painting cracked external render

Hi,
The external render on my house is well overdue for painting. The house is around 8 years old and I believe this will be the first time it has been painted since new.
There are a number of hairline settlement cracks in the render which presumably need to be filled before I paint it. Some of them are genuine hairlines, whilst others are possibly as much as half a millimetre wide.
The surface of the render has a sandy texture so I assume I can't just use the same "slap some polyfilla in and sand it down" technique that I would use on an internal wall..
Can anyone advise me as to what I should fill them with?
Picture at
http://www.rimfall.demon.co.uk/private/cracks.jpg
Thanks, Martin.
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Martin wrote:

Martin,
Have a look at this link -- http://www.sandtex.co.uk/ -- it will give you some good information.
As a matter of interest, Sandtex is possibly not the cheapest of materials, but I would recommend it, as when it is properly applied, it will last many years.
Remember that proper preparation, correct paint application and good quality materials is the secret of longevity - follow this advice and you shouldn't have to recoat the walls for at least 5 years.
Brian G
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Martin wrote:

You could use any exterior-grade filler; you just need to make sure there's no surplus remaining when it's dry; ie wipe it away when still wet as you can't sand it. But TBH I'm not sure I'd even bother: exterior masonry paint is pretty thick claggy stuff and I'd have thought would fill and cover at least the majority of your cracks perfectly well.
David
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Hi Martin, looking at the photo and perhaps someone in the trade could comment given its 8 year life but don't the cracks indicate perhaps a whole section of render is loosening off given the shape they take? If you tap the render is it starting to sound hollow behind at all ?
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Gio wrote:

Well, I had much worse cracks than than these my pebbledash render, below a downstairs window, and there was an area about 2' x 2' which was completely 'blown' as you describe, and causing damp inside the house. Rather than hacking off, I decided to try the bodge repair first: just filled the cracks with Tetrion filler and painted the whole wall with Sandtex.
This would be about 6-7 years ago. It now looks absolutely fine; the only sign of a problem is that you can hear it's hollow behind if you tap it, and all the dampness inside has gone.
David
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Masonry paint will cover the hairline ones. I'm painting my rendered house right now (Yes, yes, I'm typing on usenet...) and any bigger cracks I raked out with a triangular scraper, filled with vinyl frame sealer from Wicks and painted over. Any blown render should be removed and rerendered - we've already had a couple of sections done.
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I've recently started repainting the rendered half of my house, and found that Sandtex paint fills in the fine cracks quite nicely.
To go slightly off topic, why are houses built using render? The brick-faced half of my house doesn't seem to require any maintenance, but the rendered half (the top half of course) is going to need repainting every 5-10 years, with lots of ladder and scaffold hassle involved. Is render on top of ugly breeze blocks construction heaper than building with bricks?
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Hi,
Thanks for the opinions everyone, that's pretty much the sort of thing I was hoping to hear.
All the best, Martin.
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