Damp-proof render
 

Hi all,

When we first moved into the current house, and before I'd read on
here about the nature of the damp-proofing industry, I got some damp
men in to do the usual - injection, hacking back to the brickwork
inside, then re-rendering and replastering. It's all been fine except
where I rather stupidly cut back through the render to put in a couple
of patresses for sockets. Around the sockets the emulsion is flaking
away where dampness is coming through. This suggests to me that the
injection is a load of baloney, and that what keeps the damp out is
the render they use.

The question is how best to fix it. I could get them back in under the
guarantee, but they'll just say it's my fault for putting the sockets
in. I guess that what I really need to do is to hack back and redo the
render around the areas in question, then replaster there. I guess I
would need to surface-mount the sockets so that the render remains
fully intact. Does this sound right? And can anyone tell me what ratio
of sand to cement they use and what the magic damp-proofing ingredient
is? Is this the right sort of stuff?
http://www.screwfix.com/prods/74136/...-Retarder-1Ltr

Cheers!

Martin