A very simple question I suspect, but if I am in the middle of a full refurb and plan to wallpaper all the ceilings in the house as opposed to having them skimmed, is it best to use the tapered edge boards as opposed to the square edge? And if I am papering over it do I still need to tape to the joints?
I was thinking of using 12.5mm foil backed boards, is there a specific screw size that I should be using. Oh and should I leave slight gaps between the boards or butt them tightly together?
If your plans are not to skim ceiling this is what you should do!
Tapered edged boards 2400X1200X12.5, i'd suggest 40mm screws as wiring regs request cables to be at least 50mm when run through joist to prevent mechanical damage therefore 40mm to prevent contact with cable. Butt boards up, you can leave slight gap nothing more than a couple of millimeters and stagger joints on the 1200 width.
Joints need taping to finish job right. Use tape jointing compound (I use easyfill, there are others) and self adhesive scrim/joint tape like a thin nylon mesh on a roll.
Tapes up first then mix joint compound to a wet paste and fill out joint, this will need a couple of application sanding them down after both applications. If done correctly there sound be nice smooth level area, where tapered edge was. The angles need doing to this should be done so tape is folded in middle length ways so in contact with wall and ceiling, then meet up in the corners of room. Same application as befor with joint compound.
When everything is sanded down nice and smooth be good idea to seal with a primer before papering.
Hope explained well enough to understand and info usefull.
Regards and good look.
Remember to stay safe near electrics, safe isolation and use googles and dust mask when sanding, compound applied using trowel.
one thing that could also help you to do the job is a taping knife to fill the joint .It has a wide blade that spans the joint which directs the filler where you want it to go . you can get them from a good diy store