Plasterboard thickness

[Hitch]

So todays question... which plasterboard thickness to use...?
Is there a rule of thumb as to when 9.5 is better than the 12.5...?

Doing a bungalow loft conversion, hallway needs overbording... already has 12.5 boards and artex on most of it...

Bathroom ceiling, same as hallway, small room, 1.7x2m...
New joists above these two are at 300c/c...

Main part of the loft conversion is 12.5+25 insulated board, but the internal studwork, eg from new landing to rooms...

[aeromech3]

Good question, in Thailand I used 7mm foil backed for a suspended ceiling and have used inset downlighting but the cut out edges do crumble easily; I imagine for walls I would prefer thicker!!

[cotswold builders]

12.5 all the time, unless matching into 9.5

[steviejoiner74]

I’ve never used anything thinner than 12.5 in over 25 years unless it’s matching or patching existing.

[Hitch]

Thanks men... i'll just use 12.5 all over then

[fin]

my dads obsessed with using handi boards. they are absolute rubbish. board a ceiling with them and there is too much flex.

ive slowly managed to steer him towards using big 12.5mm boards but its taken bloody ages. he still whinges about them being too heavy like