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Repairing fine cracks in render

Postby toplondonchef » Tue Jun 22, 2010 10:00 pm

Hi all and some top advice please;
Had a 2 storey extension added to the house a couple of years ago and hope to paint the outside walls this summer
Walls have been finished with smooth render coat which now has several hairline cracks due to settlement I assume
Before painting with a stabilising solution and masonary paint, do I repair these cracks as I would with an internal plastered wall,ie. rake out crack to enlarge - remove loose material - fill with external filler ?

When the extension was being built I asked the guys rendering about repairing future cracks and they said they use Ronnerfix mixed with cement powder for repairs

Is this a good method or can you suggest a better method / material to use

Also on rendering - why is the new render so soft compaired to original render on the house

When drilling holes for hanging baskets, lights, etc I've noticed that the drill goes through the new render with no effort at all but the original render is completely different and rock hard
Had area on front of house re-rendered by different builders to extension and again found new render much "softer" than original render
Rendering looks great and is still on wall after 2 1/2 years but just wondered why so soft ?

Thanks for any help with these questions
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Postby Masheded » Wed Jun 23, 2010 5:37 pm


sounds as if the render coat was mixed with too much sand, this would explain the difference in consitency. Please be aware i am a NOT a builder or renderer. However, again i would say to you, if the cracks are not too deep ( if they are, than fill out with external filler), i would take some of the paint u already have applied, mix it up with some coarse sand to the consitency of the render, and feather out with a wet brush. This is best tried by testing on a portion of wall thats not obviously visible until youre happy with it. Other than that, its a rerender. If you decide to fill these misses with render, its worth mixing some paint up with it, which will help in the final covering. This is a DIY trick, and buy no means a proffesional solution. As with anything, if you dont wanna spend the money, its worth a look.

Hope this helps
Atb Mash
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Postby toplondonchef » Mon Jun 28, 2010 10:45 am

Thanks Masheded for the advice..

Certainly not looking at re rendering the walls as only done 2 years ago and rendering job was perfect but now just have a few fine settlement cracks

Was wondering if anyone had used Ronnerfix for render repairs and if so, is it any good

If not will probably rack out cracks and fill with a quality outdoor filler, stabalise walls and then paint

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