as flameport above,
Steaming is a nonsense - why create a sludgy mess, and why radically disturb something thats potentially problematic.
In a word why make things worse.
Again as above,
simply board over, and then tape and skim.
OP,
given that the ceiling is to be boarded then all you have to do to find joist centres is to send a 2mm or 3mm drill bit up to hit a suspected joist.
Most joists are on 400mm centres - so, having found one joist, its simple enough to work out the joist centres in any ceiling.
Do not go lifting boards and causing disturbance in the room(s) above.
Do not go buying a "jumbo scraper" - running a paint scraper, an old steel trowel or even the cheeks of a hammer head will knockoff the "spikes".
Steaming is a nonsense - why create a sludgy mess, and why radically disturb something thats potentially problematic.
In a word why make things worse.
Again as above,
simply board over, and then tape and skim.
OP,
given that the ceiling is to be boarded then all you have to do to find joist centres is to send a 2mm or 3mm drill bit up to hit a suspected joist.
Most joists are on 400mm centres - so, having found one joist, its simple enough to work out the joist centres in any ceiling.
Do not go lifting boards and causing disturbance in the room(s) above.
Do not go buying a "jumbo scraper" - running a paint scraper, an old steel trowel or even the cheeks of a hammer head will knockoff the "spikes".
