Rendering onto ICF using Sand and Cement

[Shark i]

We are considering the possibilties of using a galvanised mesh screwed onto the ICF (just for the retaining walls of the houses) to then use traditional sand and cement render instead of the Parex / silicone EWI renders that are much more expensive. Any thoughts on this? I suppose there is a possibility that it would come away from the surface of the ICF however wouldnt it bond to the mesh layer ? thanks

[Russell griffiths]

Why. 
don’t do it crazy idea 

the correct thin coat system will be cheaper, by the time you factor in the stainless mesh and the screws, then the labour to fix it, then you need a good team to render it flat. 
 

the thin coat systems are really flat and accurate and have been purposely designed for eps. 
 

sorry silliest idea I’ve heard this week. 

[TommoUK]

...ditto.  

 

...you would have to fix the mesh back to the ICF core to carry the weight of the sand & cement.  thats a lot of fixings, stainless steel to prevent rust etc , then you have to pay someone to paint it

 

..with the thin coat you will go straight on to th eps, have a better finish and no decorating

[Shark i]

Just costing up different systems is all since initally looked at the thin coat systems and was like 30 per m2 in materials obviously sand and cement cheaper there however taking into account the labour for fixing mesh and decorating after probs stacks up and considering its correct method :) do you lads generally scarify or prep the ICF before base coat with the thin coat systems? , thinking Parex at the moment

[Russell griffiths]

Get an eps rasp, big flat thing that you rub all over the joins to flatten them, then a stiff broom to take of the loose bits. 
the base render sticks like shit to a blanket. ,I have actually tried to rip sections off by grabbing the fibre glass mesh, very hard to pull off. 
 

if I was building an icf house again I would render the entire house, including window reveals, everything, even areas under cladding, just to protect the eps from stuf and to allow tapes and glue to stick to it.