"Blinding" with sand

[Lobster]

Hi I'm going to be using some bitumen-based damp-proof membrane on a wall soon; instructions on the tin say that after application I will need to 'blind' it with sand while still tacky; but doesn't go into any more detail. What exactly is involved in this? Do you just chuck dry sand at the wall so it will stick where there are any sticky areas? Presumably you don't use any form of implement to smooth the surface.

Thanks David

[BigWallop]

Blinding is like sprinkling carborundum onto stair treads to make them non slip. It's normally blown on with a wide hose thing. A bit like an upright vacuum cleaner but where the bag goes is where the sand is blown out.

[Mike Taylor]

You only need to give it a sand coating if you are going to apply a render over it. The sand gives it a key to help the render grip Usual way was to apply 2 coats synthaprufe or similar and as soon as the second one is applied throw river washed sand at it

[Bob Minchin]

Correct in every point. I assume you are plastering /rendering the wall afterwards? Otherwise there is no need to blind the surface.

Bob

[Lobster]

Thanks... well, it's actually in an outside workshop that I'll be doing this; so the only reason to render would be to protect the membrane from mechanical damage, which according to the tin can apparently happen easily. But I haven't a clue how readily damaged this stuff actually is; I'd really rather not render it unless absolutely necessary... anybody experienced with using it?

Thanks David