Advice -Need to cut square hole in plasterboard ceiling/repair?

[bilabonic]

Hi All

I have a leak in my ceiling and traced it back to the upstairs shower.
This is now repaired.

I now need to repair the ceiling as it’s damaged with hole where it was poked.

I have watched videos but it always comes up with USA based ones but I presume the process is the same?

I intend on cutting out a square that meets in the middle of the joists on sides and on the other two sides I cut I intend to fit a length of 2x1 roofing batten screwed from below through the board into the wood.
Leaving enough protruding to fix a new square piece in. So it will then be fully support on all sides.

Do I then need to cover the joints with scrim take?
If so what do I hold it in place with?
Them once it’s in place what plaster do I need to cover the patch/hole/new square if board.
I have seen patching plaster? Is that what I need?

I’m confused on the correct process.

I expect the new piece of board being fitted will be approximately 3t by 3.5ft.

Thanks

 

[motorbiking]

firstly have a good look around inside the hole for pipes, cables etc.
If the hole is big enough that it makes sense to cut back to both joists then do that.
then you can stick some CLS in both Sides and put a couple of screws in each, you now have a nice platform to attache the new plasterboard to.
Screw the new plaster board to the sister (CLS) joists and tape the edges (fibreglass tape).
Skim with top coat of patching plaster, scrape back or sand back and paint as usual.

take your time and it wont be noticeable.

If its a small hole then a piece of batten screwed to the firm plaster and then a new bit screwed to the batten, then as above. the other option is to use high grab adhesive and a bit of string with a weight to hold your batten in place, if you are worried about even more holes.