Crumbling plaster crown moulding (or coving) and tape & plaster falling from ceiling

[enkc]

I have a small leak in the corner of my shower (due to failed silcone) that doesn't seem to have impacted the ceiling below, but when I was investigating, I accientally pushed a little too hard on the plaster in the crown moulding which cracked and fell out. There's a also a crack to the edge along the crown molding - but only if I apply pressure to it.

For context, I only moved into the property a few months ago and know there was previously a leak in the bathroom which lead to a large chunk of the ceiling being replaced. I don't know whether anywork was done to try and repair the molding previously as part of this so suspect it might be crumbling because of historical water damage (or it's just old, property was built in later 1980s)

The area behind the crown molding seem to be hollow, with quite a bit of rubble / debris behind it (see photos). ChatGPT is suggesting this is quite common for builds in the 1980s (?), I also noticed the plaster board ceiling doesn't go all the way to the wall, and the crown molding is used to disguise the gaps.

As a secondary issue, I also have plaster fallig off the ceiling (around 1-2mm thick), I took out a large chunk today and now can see tape exposed.

Question 1: Could I repair the hole myself with some tape and plaster? Or does it present a bigger risk / issue that needs professional help? I have no idea what I need to do to fix it yet but am fairly handy with the correct instructions (these forums have been a great help with other issues)

Question 2: what's the best way to repair the ceiling? And can it be done DYI?

Appreciate your help.

 

[Wayners]

First picture I can see mesh tape at the edge so that's been repaired but the skimming filler has not stuck.
That's green bump was a poorly repaired water damage area. The plaster board is rotten.
I can't see any crown moulding?

 

[enkc]

The 2nd image is the coving (sorry I think i used the wrong terminology), and the 3rd and 4th is what is behind the hole.

 

[Wayners]

Oh yeah. Sorry. My mistake. I didn't look closely enough..
I guess that's 127mm gyproc coving.
Measure tight to curve top to bottom. Should be 127mm but might be 120mm if a different brand..

 

[enkc]

yes problem is I can't take the coving off without losing half the ceiling, would it be terrible to just patch it? It's cosmetic only right?

I did take more of the loose paint off the ceiling and it has revealed a patched area that has gaps, mesh falling off. I've taken as much of the tape off that wasn't sticking. Can I apply PVA solution, fill the gap, apply more mesh and then plaster over it?

 

[Wayners]

Cut out damaged plasterboard and replace with new.
Sometimes it better to remove coving on that wall and fit new.