When damp-proofing and specialist plastering works are completed it can be tempting to rush out and buy paint to redecorate. However, a little patience and planning can ensure you don’t have to decorate twice.
How long should I wait to decorate?
If you apply paint to walls too quickly following work, you are likely to find that the paint bubbles as the moisture from the plaster attempts to escape. We advise waiting 4 – 6 weeks following rendering/plastering and using a vapour permeable water based microporous emulsion. Wall papers and lining paper shouldn’t be used for at least 12 months as residual moisture can take up to a year to leave the plasterwork. Walls should not be force dried with dehumidifiers, space heaters or any other artificial form of heating as this may cause the plaster to shrink and crack as well as potentially causing specialist renders to de-bond.
What type of paint do you recommend?
We don’t recommend a specific brand of paint, but we can give some advice on types that are suitable. Vinyl Silks and glosses should be avoided as they will trap moisture: some of the emulsion paints such as egg-shell texture state that they are vapour permeable, however they may not be as permeable as typical water based matt emulsion.
What should I do if small cracks appear?
Small shrinkage cracks do sometimes appear in the set/finish plaster and this isn’t down to an issue with the render or its application. These occur because the render plaster underneath has a denser nature so the drying time between the render and set coat are different. The hairline cracks can be filled with a fine filler during preparation for redecoration.
What do I do if a white, fluffy deposit appears on the surface of the plaster?
This soft, fluffy deposit on the surface of the plaster is called efflorescence and is caused by sulphate salts which are soluble but not hygroscopic. They appear where water evaporates, leaving salt deposits behind. Where this does occur, then redecoration should be postponed until the efflorescence stops appearing and the salts should be brushed off lightly.
Is there any specific advice regarding redecoration where work has been below ground level?
Where work has been carried out in a basement or below ground level it is important to discuss this with the Surveyor involved as he will be aware of site conditions and what type of system has been used.