We've been told that we have standing water behind our kitchen units due to dodgy rendering/plastering in the past, resulting in the backs of the units getting ruined with damp. Can anyone suggest how to correct this mess? We're replacing the units and don't want this to happen again. We've been told to knock all the existing render/plaster off and leave the walls to dry out, but then we need to know what to do next. How do we make the walls good again?
It's not quite that easy to explain how to render and plaster, and even harder to master, if you have never done this before? Takes more than one application.
I'd suggest that you get an expert in, the time they will save and the assurances that the job has been done correctly is well worth it.
Its very unlikely indeed that any damp behind units is due to plastering, bad or atherwise. Plastering is simply a way of providing a surface to decorate, not to hold water back or provide damp proofing of any kind. Plastering which is intended to hold back water is a very specialist field indeed and requires much more than a couple of bags of plaster. If the cause has been identified as bad rendering on the outside of the building it may need to be replaced but if you have been told to "leave the walls to dry out" it sounds like the internal plaster.
The root of the damp needs to be found first so you can deal with cause, not effect. Our projects section contains many projects on damp and damp proofing and when the cause is identified and remedied (see also our project on condensation which can happen very easily behind units and wardrobes) you can look at the projects we have on base coat plastering and top coat plastering.