Fireproofing RSJs in ceiling

[kingandy2nd]

Hi folks,

I have RSJs in the ceiling under which I plan to fit a flush ceiling in plasterboard.

Do I need to box the RSJs with fireproof plasterboard put up the sides too, or can I just put it across the bottom in line with the ceiling?

If it’s the latter, does the whole ceiling need to be FP plasterboard or can I centre the 1.2m side of the plasterboard so that there’s a width of 450mm of pink plasterboard either side of the RSJ?

I found this thread but seems to be a bit conflicted, so any help gratefully received.

https://www.diynot.com/diy/threads/fireproofing-rsj-in-ceiling.506498/

Thanks
Andy

 

[^woody^]

The ceiling is the fire protection - 30 minutes

 

[kingandy2nd]

The ceiling is the fire protection - 30 minutes

Thanks woody, but for clarity are you saying the whole ceiling needs to be done in the fireproof plasterboard?

 

[^woody^]

Normal 12.5 board and skin gives 30 minutes, so as long as that is what's used on the ceiling that protects the beam too

 

[kingandy2nd]

Ah ok thanks, I have plenty of 12.5mm PB and it will be plastered, so I’ll run with that. Thanks again