Tiling over new skimed plaster

[Marksim]

Hey I'm having my bathroom plasterd 3 of the walls the plasterer is going to skim over the old plaster as it is firm and 1 wall he is dot and dabing plasterboard on to then skiming this. How long do I need to leave the plaster skim to dry before I can tile? Thanks so any info.

[toplondonchef]

Hi Marksim

Plaster skim coat is pretty thin, approx 3mm so will ususally be fully dry in 2-3 days
Keep the bathroom door open to aid airflow, the window slightly open during the day to allow water vapour to escape and I'm guessing that the heating will be on in the house, again helping the drying time
You can see the plaster drying out over time and change in colour from dark and damp looking to an even light pink colour

Just wondered why your having the walls skimed if your then going to tile ?
Are you tiling just half way up the wall or full hight

Hope that this helps
Regards

[chris_on_tour2002]

if you do it according to the textbook the you'd leave the plaster for 28 days to fully cure before tiling. up to your conscience though in reality most people tile as soon as the plaster is dry. NEVER be tempted to tile on wet plaster.

personally though i wouldn't skim the plasterboard where you are tiling. you'll get a stronger bond if tiling directly onto the plasterboard and have the advantage that no sealing will be required.

the plaster skim simply adds an extra unnecessary layer and a needless potential failure point. also the skim will be able to bear less weight per sqm than the plasterboard alone. i forget the exact numbers but plasterboard will take something like 20kg/sqm with no skim. this drops if skimmed.

[Marksim]

his skiming the other walls as the plaster is quite uneven as it had tiles on before. Thanks for the advice. Do I need to prime the plaster with anything? I've never done when I've tiled plaster before, but read some people do.

[chris_on_tour2002]

you do need to seal the plaster with a tiler's primer if you don't want them to fall off.

use an acrylic or latex primer available from any tile shop. don't use PVA.