I have a bathroom to tile where the old tiles are coming off the plaster leaving it in a good state. Should I prime or seal this plaster before re-tiling?

What tiles and adhesive will you be using

If the tiles are coming off and leaving the plaster in a 'good state' then there is something wrong with the way they were fixed initially.
So you are right to ask the question!
Answer Whitebeams post and see what happens!.

John.

what plaster is on the walls? is a gypsum or a sand/cement render?

if the plaster is in good condition and you are using tubbed adhesive there shouldn't be any need to prime!

Hi guys, thanks for all the replies.
I have BAL tubbed adhesive and ordinary ceramic tiles. I don't know when the existing tiles were put on but it was a long time ago and very DIY. This is in a residential care home (converted from big house) so I think the plaster is the usual domestic stuff. I will only be putting about 3-4 tiles high around the bath.

Hi susiequ.

Bal make an acrilic primer for plaster walls so prime your area first before tiling.
Has the old tiling been done on top of emulsion paint?
If so scratch it off before priming.
Keep in touch.

John.

Thanks John, no paint so far, but I do have a primer for painted walls if necessary.

Originally Posted by Susiequ

I have a bathroom to tile where the old tiles are coming off the plaster leaving it in a good state. Should I prime or seal this plaster before re-tiling?

You may find that when the old tiles were put on, either they didn't use a primer or they used PVA, which was common place in the older days (still is for the less informed tilers/plasterers/would-be tilers/etc). Over time, the adhesive bond to the wall can fail and the only thing keeping the tiles up is the grout...

Provided your chosen tile weight is ok for fixing to plaster, make sure the plaster is completely clean/free of old residue and then check the instructions of the adhesive you plan to use, because some may want the walls to be primed and others may not...

Originally Posted by Susiequ

Thanks John, no paint so far, but I do have a primer for painted walls if necessary.

far better to remove the paint SQ, if I can(remember)tomorrow I'll take a photie of the tool I use to remove paint