How to Replace a Suspended Ceiling Using Plasterboard?

[Sweetpotato2]

I am looking for guidance in replacing suspended ceiling tiles with plasterboard fixed directly to wooden joists.
Currently we have cold flat roof, excellent condition with vents in soffits all around. However, the suspended ceiling is ugly and would like to replace it with plasterboard so it looks like a normal ceiling. The rock wool inuslation is above the joists and there is plenty of ventilation via the soffit vents.
Could you provide advice or a step-by-step guide for this process, considering the existing insulation and ventilation setup!

 

[Monkey Boy]

Selco do a suspending ceiling system called “MF CEILING SYSTEM”
Step by step guide on YouTube

 

[Sweetpotato2]

Selco do a suspending ceiling system called “MF CEILING SYSTEM”
Step by step guide on YouTube

Thanks, but I hope to have no suspended ceiling at all and replace it with plasterboard which will be screwed to the wooden joists.

 

[essexandy]

Thanks, but I hope to have no suspended ceiling at all and replace it with plasterboard which will be screwed to the wooden joists.

As an absolute minimum you need to remove the Rockwall from between the joists and replace it with Celotex, or similar. A lot depends on the depth of your joints. You need to maintain 50mm of airflow above the Celotex. You really want a total thickness of Celotex of around 150mm, to achieve this you fix sheets of Celotex to the underside of the joists before covering with plasterboard.

 

[paulf]

As an absolute minimum you need to remove the Rockwall from between the joists and replace it with Celotex, or similar. A lot depends on the depth of your joints. You need to maintain 50mm of airflow above the Celotex. You really want a total thickness of Celotex of around 150mm, to achieve this you fix sheets of Celotex to the underside of the joists before covering with plasterboard.

@The Advice Guru
What's your advice?

 

[Sweetpotato2]

Thanks guys! However, why would you need to remove the rockwall? One problem - not sure how to check if there is a 50mm gap with the existing rockwool above the joists, which has a clear plastic sheet layer underneath. I am not keen to puncture the plastic sheet or wrap just to measure inside. The airflow is below the insulation and flows out to vents in soffits.

 

[essexandy]

Thanks guys! However, why would you need to remove the rockwall? One problem - not sure how to check if there is a 50mm gap with the existing rockwool above the joists, which has a clear plastic sheet layer underneath. I am not keen to puncture the plastic sheet or wrap just to measure inside. The airflow is below the insulation and flows out to vents in soffits.

How is there Rockwall above the joists on a flat roof construction?
Rockwall doesn't have the thermal qualities of Celotex and the air gap has always been above the insulation on any construction I've seen, otherwise you've got cold air getting below the insulation.

 

[Monkey Boy]

Thanks guys! However, why would you need to remove the rockwall? One problem - not sure how to check if there is a 50mm gap with the existing rockwool above the joists, which has a clear plastic sheet layer underneath. I am not keen to puncture the plastic sheet or wrap just to measure inside. The airflow is below the insulation and flows out to vents in soffits.

To make an omelette ya gotta break some eggs

 

[ChrispyUK]

Thanks guys! However, why would you need to remove the rockwall? One problem - not sure how to check if there is a 50mm gap with the existing rockwool above the joists, which has a clear plastic sheet layer underneath. I am not keen to puncture the plastic sheet or wrap just to measure inside. The airflow is below the insulation and flows out to vents in soffits.

Sounds like a bit of a fudge. The air gap and ventilation should be above the insulation with the vapour barrier beneath.

From what you’ve mentioned, the insulation is probably doing very little, unless it’s got lost in translation

 

[essexandy]

Sounds like a bit of a fudge. The air gap and ventilation should be above the insulation with the vapour barrier beneath.

From what you’ve mentioned, the insulation is probably doing very little, unless it’s got lost in translation

Stop copying my answers you f**k**g chancer.

 

[ChrispyUK]

Stop copying my answers you f**k**g chancer.

Shut up