ceiling regs for kitchen re plasterboard?

[pmcx9]

i am about to embark on plasterboarding my ceiling in a new extension which will be a kitchen. Someone in passing has just said they think it will require double skinning with 12.5mm plasterboard. Is this correct?

It is a single storey extension with a flat roof that has been knocked through into a room in the main house, with 2x4" steel rsj's in place holding up the external wall. The roof is a warm deck with foil backed 76mm kingspan insulation. Can I single skin the ceiling if I clad the rsj's in a seperate skin of plasterboard?

cheers

 

[pieman]

check with your building control officer.

I think that the rsjs may need double skinning (they are supporting a wall and presumably that is supporting an upper floor) but the ceiling to the flat roofed single storey bit is probably ok with single skin.

but the buck stops with the bco - check with them!

Building regs approved documents here

 

[JerryD]

In my area a single skin ceiling is perfectly ok except in a garage with a bedroom above. (that does need double boarding)

The steel will have to be double clad though, with staggered joints and a plaster skim. This gives it the required fire protection.

Still check this with your bco as every district has their own interpretation of some of the rules i'm afraid.

 

[pmcx9]

thx for replies fellas. the steel is recessed up into the ceiling so very tricky to clad in plasterboard except the underside. i was gonna double skin the underside anyway,

 

[JerryD]

If the steel is within the joist space (i.e. not visible from above or below) then you don't need to provide separate fire protection for it.

There's no requirement to fire clad the steel beam unless it is below the ceiling line as a 'downstand'

 

[Prefix]

Sorry to butt in guys, but I just had an rsj fitted in my kitchen. It is supporting the staircase and the above floor. I have ripped out the kitchen, back to bare brick, battened and plasterboarded the walls and ceiling (incorporating recessed lighting). I also plasterboarded around the rsj, using wooden noggins and 'no nails'.

Could you tell me what 'double skinning' is and why it is needed? Have i done something wrong? Are there any regulations I should know about?

Cheers in advance guys..

 

[masona]

Could you tell me what 'double skinning' is and why it is needed?

Just that, double thickness, 12mm plasterboard is a 1/2 hour fire protection and 24mm is 1 hour.