making sure existing plaster is sound?

[elmsoft]

I am re-tiling an old bathroom and the existing tiles have come off really easy - worryingly easy- leaving traces of the original adhesive. The wall surface is plaster on brick and probably original ( Victorian). The plaster seems securely bonded to the brick.
What is the best surface preparation to make sure that the next lot of tiles are fixed more securely?

 

[tpt]

sounds like the plaster wasn't primed properly - its quite common. use an acrylic bonding agent and then a quality adhesive (not diy shed c**p) such as bal, granfix, weber, ardex. make sure you use a notched trowel - dont dot and dab the adhesive.

you can check the plaster easily by knocking it with your knuckle and checking for a hollow sound. in general though, if you have just chopped tiles off and the plaster is intact it sounds pretty good.

 

[elmsoft]

Thanks for such a helpful and quick reply.
Only ever used PVA as a sealant and gather a bad idea for wet areas
So a google search found Granfix acrylic bonding agent. That the stuff you mean?

thanks again

 

[tpt]

yeah pva used to be the way. these days avoid it for anything tile based.

Yep granfix acrylic is a good brand.