Scrape off.
Old emulsion under. Bit powdery?
Here we use gardz to penetrate as and bind surface.
Make good with filler and paint.
Get up in loft and add more insulation so the ceiling dont get cold which will reduce or even stop condensation forming on the surface.
Or fit plastic panels to ceiling
Internal plaster?
Options...
Plastering mesh 100m x 1m rolls. Used along with multi finish plaster.
Fibre fuse rolls layed over sprayed on plaster covering walls.
Wallrock lining paper 1m wide run horizontal I have done it with smaller roll along the top.
Only 2 joins to deal with that way
Check outside drain gully. Rain water can get through cracks in drain capture and get under the house.
Make sure all the water in all the drains goes down and away as it should
Never put panels at the back of a wardrobe because the wall doesn't get air movement and heat from the house and condensation forms behind.
Could be that.
Cut a hole and look behind side panel to confirm
Sound travels through solids.
If you had foam with metal sheet then foam suspended in the air then sound won't get through as the metal will move in between the foam canceling out the noise.
Foam don't block noise but allow the solid to move (plasterboard) which will create a sound barrier.
If...
Board foam.
Proper way is resilient bars. Don't let board touch edges like the floor or walls.
When fixed fill edges with acoustic mastic. Plaster.
If you go with foam don't let boards touch edges again.
Go deep enough to hit solid ground and bigger at the bottom of hole than the top. That's way it won't pull out.
Around ¾ of a bag per hole if you don't dig it too big. Keep it narrow and deep.
The swing legs don't need to be deep just held in concrete
They are recommending 6 days to cure in the open air then you would apply rocktop.
Good drying at the moment so 3+ days it would probably be fine.
Depends if your in a hurry