Rendering exterior walls of a brick house

[nick41711]

What's the best mix for rendering an exterior wall and how do I work out how much I need to buy of materials ?
Thanks Nick

[Grumpy46]

On a exterior wall make sure the wall if dust free & no rising damp, then apply a coat of exterior PVA.
A mix of 4 sand to 1 cement a 25Kg of sand would cover around 1sqm subject to the thickness of the rendering
So if you have a lot of rendering to do get a jumbo bag and work out how many 25kg you would get from one of these.
You would need around 8-10 bags of cement for a jumbo bag.
You would need to paint the new rendering when dry of add a water resistant additive in with the mix

[buildersmate]

Soft sand, not sharp sand.
Render is usually around 13mm thick in total, applied in 2 coats.