Crazing Render

[DonVin]

Hi everyone,

I would really appreciate some advice on this.

I had the front wall of our house rendered in April 2009. As far as I understand it was a cement/lime mix applied in two coats (scratch and float?) and painted.

I was very pleased with the finish however it started showing hairline cracks a couple of months later. They were easily painted in so I was not too concerned. However these have continued and it now looks like crazing (it has worsened with the warm weather).

On the lower part of the wall the cracks are very fine but closer together (say 30cm), on the upper part of the wall the cracks are more visible and slightly wider but further apart (say 1m). Some parts of the wall show no signs of cracking at all.

I have called the contractor back a couple of times and they have basically said that render is prone to cracking.

My question really is - what can be done to repair the cracks? If they are filled and painted over, will the cracks just re-appear?

The render appears sound and solid.

Cheers.

 

[external]

there are many reasons render will crack,maybe the render was to strong for the background as this will bring the kind of thing you describe,it may be solid now but unless you deal with the cracks you will get water ingress that will blow in the end,consider an acrylic primer then an acrylic texture,myself i have never seen it crack as long as the background is sound,the trick is a few coats of primer which should fill small cracks.

 

[DonVin]

Hi external, thanks for the response.

So will the acrylic primer and paint give a different finish or is it still relatively smooth? Can you recommend a product?

Also would it be best to leave it a while to see if more cracks appear? I am worried that I will repaint, only to find more cracks appear after.

Whatever I do, I will need to repaint with the same masonry paint as the rest of the house (only the front wall is rendered) after.

Thanks again.

 

[external]

acrylic textures are floated so give a smooth finnish,if the rest of the house is painted and the colour is to british standard weatherby will be able to match with thier range of heck siliconharzputz,theve got their own tint machine.

 

[DonVin]

Thanks again external, I will look into this. Sounds expensive though especially as I have not long paid for the job. Perhaps just an DIY acrylic paint job for now?

 

[external]

the mats work out to about £12 m2 which aint to bad mate all things considered

 

[DonVin]

the mats work out to about £12 m2 which aint to bad mate all things considered

That's doesn't sound too bad but would still be over £1,000. I will look into it and consider in a year or two once the extent of the probelm is clear.

For the time being I think I will just seal the cracks to protect from water ingress and re-paint towards the end of teh summer.

I was thinking some kind of paint on liquid sealant. The cracks are too fine to fill with anything else. Any suggestions on what I could use? Maybe external grade PVA?