How to repair cracks on fibre cement vertical walls?

[Bel789]

My house is clad in fibre cement large flat sheets. A crack has developed on the surface that is irregular in shape and not on a join, nor is it straight. 

Until I can afford to reclad, I need to repair this, so it hopefully lasts 2-5 years. 

Any advice appreciated! Thanks.

[MitchellMc]

Hi @Bel789,

It would be beneficial for our members when offering advice if they could see the crack that you're dealing with. That will give us a better idea of repair options.

You might like to read this helpful guide: How to repair a rendered wall. Much the same techniques will be used with your sheet cladding. If the crack is not too severe, you'd likely be able to effectively fill and repair it with Sikaflex 11FC. Simply apply caulk it into and over the crack to seal it. This isn't a structural repair, so the crack might continue until the underlying issue is resolved.

Please let me know if you have any questions.

Mitchell

[Bel789]

Thanks for your reply. These are the cracks. This photo is about 30cm high. It doesn't go very much further.

They are relatively fine so not sure if I need to make them a little wider before patching. It is only on one sheet.

I believe there is metal cladding underneath the fibre cement in this area which may have caused it - different expansion/contraction rates?? It is also the area that gets the most sun.

Just trying to buy some time before recladding in colorbond.

Thanks!

[EricL]

Hello @Bel789 

It is difficult to tell the cause of the expansion, it could be ground movement, thermal expansion or frame movement or a combination of all three. But let's hope that the area has settled down and that there are no further movements in the future. If the cracks are very fine, you should be able to just cover it with the Sikaflex 11FC.

Please keep us updated with your progress, we look forward to seeing your fibre cement repaired.

Eric