Roughcast / pebble dash over cement boards

[colu]

Hi,
I'm currently struggling to sort out a suitable render finish for my timber frame extension that’s been built. It’s been clad in Shera Cement boards and needs a rough cast finish to match in with the rest of the house. Ideally this would be with a through colour render (white) to save on painting. I’ve been offered a couple of options so far:
1 Weber or Knauff base coat with fibre mesh and sand & cement top coat to match in with the existing house.
2 SBR slurry, either EML or fibre mesh, sand and cement base and top coat but no guarantee offered if it fails
The area is about 60-65sqm.
Any advice /help would be appreciated
Col U

 

[stevethespreader]

Never heard of them so I googled to see what would be best it says nothing about rendering on them only cladding and veneers ect http://www.sheraeu.com/mobile/Boards.html

 

[colu]

Hi,
I've spoken to the manufacturers and they are happy for render to go over them. Essentially they are cement boards similar to aquaboards.

 

[stevethespreader]

It don't say anything about render in the specs knauf give detailed instructions on how and what render to use with the aqua panels they also invite you to phone up and ask what render systems are compatable, if your boards are the same I would give them a call I'm not sure why they don't say anything like that with your boards, tbh I have never rendered over such boards but if asked to I would phone the manufacturer up and ask the what render to use ect , I was on a site 2 years ago and everything on site was knauf and aqua panels was used in the swimming pool area of a premiership club training ground and they used knaufs own render system

 

[stevethespreader]

It don't say anything about render in the specs knauf give detailed instructions on how and what render to use with the aqua panels they also invite you to phone up and ask what render systems are compatable, if your boards are the same I would give them a call I'm not sure why they don't say anything like that with your boards, tbh I have never rendered over such boards but if asked to I would phone the manufacturer up and ask the what render to use ect , I was on a site 2 years ago and everything on site was knauf and aqua panels was used in the swimming pool area of a premiership club training ground and they used knaufs own render system

Looking at it if the manufacturer of your boards do not have a render system to go with their boards I would see if I can go with option 1 knauf base coat with render topcoat but I would phone knauf first because the render may be heavier than the knauf base coat and may cause a problem so I would ring them and ask, there used to be a man on here called imperial complete solutions that could give u all the advice you need on such renders I don't think he's about anymore

 

[colu]

Thanks for the advise, so there would be any problem using a sand and cement top coat on something like knauf in terms of cracking or similar? The boards can take 40kg/m2.

 

[stevethespreader]

You did not read advice properly I said that the render could be to heavy for the knauf base coat so ring them and ask, you should have thought this through before using the boards you have but did you know k rend do a roughcast finish? Which is worth looking at? http://www.k-rend.co.uk/products/additional-proudcts/Silicone-roughcast-krend?

 

[colu]

Hi,

Understand now, I would be interested in using the roughcast k rend product but I've struggled to find anyone confident in using it.