Tiling bathroom, to prime or not

[markwm]

There's a variety of surfaces to be tiled in our bathroom:

New Exterior Plywood
New unplastered plasterboard
Old plastered plasterboard
Old lime plaster


Our tiler mentioned he would PVA everything but I'm not going to let him do that. I have some BAL tile primer, am I better off slipping him this instead to use for everything?

 

[uppatree]

Don't prime wet areas with pva, if it comes in contact with moisture it can re-emulsify. Give your tiler the bal primer. SBR bonding agent from sovereign chemicals works well also...