Sand/Cement render over Paint on Liquid Damp Proof Membrane

[markyuk]

Hello
this is my first post after reading a lot on the forum for a while now

just a quick question
i have a wall that i have painted Liquid Damp Proof Membrane (BlackJack type stuff)from a well know DIY Store on to the brickwork
i was going to render with sand and cerment mixed with bit of waterproofer as a 2nd barrier, but the can said only to plaster not render with S&C

Why is this, i was worried if i plastered and the Damp Proof Membrane paint didnt work propally the plaster would get wet and blister, thats why i was going to S&C render

what do you think

this is an internal wall in the kitchen and is a solid wall with no cavity

thanks very much

Mark

 

[tim00]

Hi, if you had researched on the Building Forum you would be aware of the various experiences with paint or spray on "waterproofing" agents. In brief, they cause endless further difficulties.
However, you've applied the stuff, so I'd suggest scratching on a couple of small patches of cement slurry made over with a little 1L:1C:4S mix, and seeing if they take to the background.
Come back after watching the experiment for say 48 hrs.

You cannot use browning or "plaster" in a damp situation, and it would pay you to find and eliminate the cause, or causes, of the damp.