i'am putting up green back plasterboard in my bathroom. before painting it would i have to seal the plasterborad or skim or can i paint staright on top ??

You mean green 'faced' moisture resistant plasterboard? You should be ok painting straight on top of these,joints can be filled first with easi-fill joint cement & sanded flat.(paper tape can be used on tapered edge boards) If you skim them you are taking away the whole point of them being moisture resistant and because MR boards contain silicone,you will need to prep them first with a plaster bonding agent such as Thistle Bond-It or Febond Blue-Grit,Wickes PBA etc....to give the boards a 'key' as plaster doesn't really like silicone. This is in accordance with British Gypsum guidelines. I would just fill & sand the joints and paint them & any areas to be tiled can go straight onto the board. Carl.

Hi , i pretty much agree with Carl,but id go with Toupret and Toupret extra fine scrim,abrade and paint with a Clixtone paint to compliment the boards, this paint will add to the protection and not take anything away from the boards job.

The vet areas should be tiled and other areas could be tape and jointed then painted.