Looking for a little advice on how to finish plasterboard

[DannyJM1]

Hi all. I'm new here, hoping I can get to learn a few things from the forum about diy around the house. I have lots of work to be done around the house and if I can save a great deal of money doing some work myself and learn some new skills in the process then I'm eager to learn. I'm looking for a bit of advice this evening on plasterboarding.

I have just about zero diy experience and have taken on the task of renovating my attic room. I recently had a roofer fit a new skylight after the old one was allowing in water - couldn't get it sorted right away so inevitably I ended up with some nasty damp issues which in the end completely ruined the walls which are... well were... constructed of lathe and plaster. I got some boards from B&Q, ripped the walls down and put board up, taped the joints and applied some filler. While I was at it I even replacing the old light and double socket and also set them into some drywall boxes for a nice clean and slim look. raised the socket about 120mm as anything I plugged in ended up with the flex pretty much digging into the carpet. Didn't seem so safe. Here is a couple of pics from my project so far. Still got one more wall and the ceiling to board. Third wall I will leave be and simply apply some filler to any knocks because the lathe and plaster is still in good condition there.



I'm pretty proud of the job I managed especially being my first real go at diy. Ok so I realised I've made a bit of a mistake after taping/filling. I've used square edge board but hear that the tapered stuff is better because you can properly load the joints up with filler and get it really smooth and the tape will be completely hidden (something I've not managed to do). But I plan to get around this by adding some heavy lining paper which I can paint onto, correct? No plans to skim so far...

So a couple of questions...
will lining paper get me a smooth finish to paint onto?
Do I need to apply any kind of primer or base coat to the plasterboard before applying a lining paper? I've heard of doing this when painting directly onto the board.. I'm guessing the same principle applies when using wallpaper paste?
(if necessary to do) will priming prevent tearing/damage of the boards should I ever need to remove the lining paper?

[steviejoiner74]

You can still feather the joints and sand smooth with easi fill to give you a finish ready to paint,no need for lining paper.
The tapered boards are only tapered lengthwise anyway and the square but joins still need taped and filled.
You’ll just need to feather the joints out 3-4 inches away from the join of the board and sand smooth.

[cotswold builders]

You need to go over the joints a couple more times, sanding inbetween and feather out.

You also need to seal the boards especially if painted over, although the wall will be flat, stripes will show through regarding painting on 2 different materials.