Hi,
Our Baxi boiler has been playing up for a few weeks now.
I have to keep the water/radiators switched off because when i turn the switch to water only the radiators also come on hence why i turn it off as it'll cost me a fortune in heating. Also when i turn on the water the boiler...
didn't bond it. Put neat PVA on waited to go tacky and put a coat of multi finish, PVA again in the morning and put 2 coats of multi. Looked at the wall the other day after joiners had finished with skirtings etc and the wall looks fine
I would draw a level pencil line across the wall break off any plaster etc abount an inch below and then carefully hammer and bolster across the line to give a nice straight finish to make the new plaster to blend to.
i've just done a job recently in which the clients had wallpapered woodchip onto plasterboard, had to steam and scrap it off which did bring alot of the paper coat of the plasterboard. The boss told me just to PVA it put a coat of multi finish on and reskim as normal the next day.
you could either nail your bead on with plasterboard nails into the mortar joint also you could try dot and dab adhsive (tack with nails to hold it) but make sure you prop your bead underneath to hold it up and make sure it's all level
If not trowelmonkey1's idea you could try putting longer noggin's up the length of the stud wall, set it back the thickness of some plywood and then screw the ply to the noggin's so it is flush with the stud wall. This way when you attach your shower screen you don't have to worry about missing...
To be fair when we've used it neat we have never had any problems.
If your taught one way you tend to stick (parden the pun) with that unless someone else tells you any different. I think thats why so many peolpe get confussed or misslead when doing something