Which Plasterboard do I use

[moe100]

Hi all,
Just a question regarding the plasterboard type I should use for a single storey extension, used as a kitchen in order to meet Building control requirements.
I was about to order standard 8x4 12.5mm plasterboard for the kitchen ceiling and fire retardent plasterboard for the rsj but the guy said maybe all the boards needed to be fire retardent

anyway can someone please confirm the following for me

extension ceiling
do I use standard 12.5mm plasterboard or does it need to be fire retardent plasterboard.

RSJ fireproofing
to cover this, do I use a double skin of 12.5mm fire retardent plasterboard with stagered joints nailed to wooden soldiers

Thanx in advance

 

[noseall]

12.5mm plasterboards are suitable for virtually all fire regulations in a domestic scenario. fireline boards are usually used to protect a bedroom from a garage below.

i have known building control sanction the use of a single layer of 12.5mm boards and skim to box in steel beams too. i'm not 100% sure but i think 12.5mm skimmed boards offer 1/2 hour fire resistance. ask your building control officer and he will be glad to advise.

 

[Richard C]

Only thing I would add is to consider using foil back plasterboard for the ceilings; having used it to refurbish an old 60’s flat roof extension, it seems to have made a noticeable difference to heat loss. For the small extra cost involved, I would always use it in the future.

 

[moe100]

thanks chaps

Richardc,
Is foil back plaster still advisable if the flat roof is of a warm roof construction (Kingspan with integrated ply)


Noseall,
so standard 12.5mm plasterboard should be adequate for the whole job and double skinned for the steel.
not sure I feel safe using a single skin on the steel

 

[Richard C]

thanks chaps

Is foil back plaster still advisable if the flat roof is of a warm roof construction (Kingspan with integrated ply)

My flat roof is 1960's & cold construction with (now) 200mm of insulation between the joists & a ply/felt deck roof. I confess I can't answer your question as I am unfamiliar with the theories behind warm roof construction. Presumably this retains residual heat in the air gap within the roof space but you’ve got me thinking & I will have to bone up!

 

[markie]

1/2 " plaster boards offer 1/2 hour fire resistance, been putting them up for the past few days, and i'm pig sick of the sight of them

 

[^woody^]

The important thing with fire-lining steel beams, is that the fixing method is such that the plasterboard, or whatever is holding it, does not fall off in the heat of a fire.

Timber wedges are not good enough on their own - they should be secured with wire or bolts etc. Same for plaster dabs.

And structural beams require protection to a standard at least a good as the element it supports, so it can vary from 30 to 90 minutes.

 

[moe100]

Chaps, Can I use a single layer of 12.5mm fireline plasterboard then,

Woody, do you mean the noggins should be secured with chicken wire? Also, how do you secure the bottom board to the RSJ

 

[noseall]

thanks chaps


Is foil back plaster still advisable if the flat roof is of a warm roof construction (Kingspan with integrated ply)

yes, use foil back board below the roof.

as for fireproofing, ask either your bc officer or designers advice as to the fire rating value they need. i'm sure fireline boards will be fine.

 

[supernelly]

Building regulations are iregular from council to council.

If you use fireline on the steel and use the rest up on a ceiling then use normal 12 mill for the rest no one can complian really.


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[moe100]

Cheers all,
parts delivered.

single layer 12.5mm fireline for the steel and standard 12.5mm for the ceiling