Patching hole in ceiling

[chilluk]

I have had to cut out a hole in the plasterboard in my kitchen ceiling due to damage from an old leak. Hole size is just under 2 x 3 ft.

I have trimmed back to the nearest joists so I have something to fix to, and secured new edges of existing plasterboard. I have also taken off the plaster skim surrounding the hole for about and inch and a quarter, with the intention of having a sort of rebate for taping the joint.

Existing plasterboard seems to be 12mm (12.5?).

When screwing new piece of plasterboard back up should I also batten along the unfixed edges and mechanically fix to existing plasterboard?

What length screws - 35 or 50mm?

When taping I think I will be better with the type of paper tape that is used with jointing compound rather then self adhesive scrim type tape - reason being that where I have to make the rebate isn't 100% smooth all round - is that OK?

And then to finishing the repair and blending it in with the surroundings - do I need to prime the plasterboard with anything?

The jointing compound I was looking at seemed to suggest it was for finishing too. Can I use that to skim the new piece of plasterboard? Or do I need to get some sort of finishing plaster instead? For such a small area can I use a ready mix product?

Thanks

 

[foxhole]

Battening loose edges is not essential , 35mm screw is fine, scrim and fill, this is easy to use and sands down well.

Gyproc Easifill 60 Filler

If you're looking to repair interior walls or fill plasterboard joints quickly and easily, you'll love this Gyproc Easifill 60 filler. It has a set time of just one hour, giving you a faster finish and helping you get more done.EasiFill 60 combines setting and air-drying, so can be used for both...

www.toolstation.com

 

[chilluk]

Thanks for that. Sorry a few follow up questions.

What's the best tool to smooth it out, is it better to get some sort of straight edge that is a little wider than the overall hole width so I can follow the existing ceiling?

Do I need to seal the plasterboard before applying?

Looking at the existing skim it's about 3 or 4mm thick. Will I have to apply in several goes to build up to that?

Cheers

 

[Scally-Ho]

If you are looking for spot on straight edge, then IMO a 4ft plasterer's derby definitely fills that role. £20 well invested

Aluminium Plasterers Darby

Lightweight and strong aluminium plasterers darby with wooden handle.

www.toolstation.com

 

[foxhole]

Thanks for that. Sorry a few follow up questions.

What's the best tool to smooth it out, is it better to get some sort of straight edge that is a little wider than the overall hole width so I can follow the existing ceiling?

Do I need to seal the plasterboard before applying?

Looking at the existing skim it's about 3 or 4mm thick. Will I have to apply in several goes to build up to that?

Cheers

You can apply in one coat , sands easily, no priming required ( though some might suggest pva first).
Many items can be used for straight edge , level, have used metal threshold bar in past or section of Ali angle .

 

[Wayners]

I'd use plaster with half time in then skim over. Watch... on the trowel....on YouTube for patching.

You can use easyfill but keep mixing a new batch every 30mins. Keep applying a fresh mix over a set mix as going over damp filler is no problem.
When filler dries it's horrible to fill over.
Fill all joints before you apply tape.

Fix wood all the way around opening. Screws all the way around.
Fibre fuse is the best tape IMO.
Paper is not easy to use.
You might get on better with 30% thinner mesh tape and easier to source. It's called Gyproc FibaTape Perfect finish