Do I need to re-plaster before I re-tile? Ask your questions and find answers on many subjects relating to plastering and dry lining

[twowheeledboy]

I have just discovered that my shower has slowly been leaking through the grout in the tiles and then behind the plaster in my bathroom. It looks like it has been happening for sometime and is now showing signs behind the plaster downstairs under the bathroom.

I have removed some of the tiles and with them has come much of the surface plaster.

The house is about 200 years old and therefore has no cavity walls and is built of old stones, the wall behind the plaster isn't the old stones but looks like render.

I will remove all of the damp surface plaster and let everything dry out but do I need to replaster over, what looks like, the render or can I just tile over the top? Do I need to apply a sealant before re-tiling and how long should I give everything to dry out before re-tiling?

Any help that anyone could give would be very much appreciated! Thank you.

[chris_on_tour2002]

you can tile straight on top of the render, you don't necessarily need to replaster - you're only adding another layer and potential failure point.

however you will need an even and flat surface so it might be that you will need to build up to level if you are going to try to replace only a few tiles into existing.

how long you need to leave to dry, well it takes as long as it takes, depends on how sound the render is how damp the walls are how warm and humid the room is etc. a dehumidifier will speed up the drying process.

you will need to check the render for soundness, give it a tap once dry, if it sounds hollow you will need to remove and reapply otherwise your render will fall off bringing the tiles with it.

and yes you will need to seal first - use a tiler's primer acrylic or latex based. any tile shop should sell it, don't use PVA.