Workshop Ceiling Query

[Popshw]

I'm looking to install a plasterboard ceiling in the workshop purely for aesthetics. Will be painted and will install some LED panel type lighting.

Aside from installing the plasterboard and taping etc. What else do I need to consider, insulation?, vapour barrier? ventilation?

Some extra information, the space isn't heated, haven't had any issues with damp or rusting of tools, there is a playroom come spare bedroom above which is rarely used but may be used more frequently in the future. Attached are some pictures of what I'm dealing with.

Any advice would be much appreciated.

TIA

 

[Sideways]

In my unheated, flat roof garage, I put up four sheets of one side bitumen (?) coated chipboard. I left space around the edge for air circulation and find it handy to be able to screw hangers into the ceiling as needed. It was good protection for the contents of the garage when, inevitably, the flat roof needed to be re-covered,
Your situation s quite different but I wonder if fire retardent MDF board or some such with greater physical strength might be a better choice than plasterboard.

Other thought, consider running dust extraction pipes in the space above before you fix the boards. Same for a compressed air pipe. It can be handy to have a hose dropping down from above the workbench or table saw, piped to a vac that doesn't need to move around so much. Same for a compressor and even a power socket hanging from a chain. Overhead services reduce trip hazards.

 

[Old.bodger]

I suspect the text book answer is that you should check building regs!
To be more helpful. Two layers of 12mm fire board (the pink plaster board) will get you in the right direction. Stagger the joints on the two layers.
Insulation optional. I don’t think you really need a vapour barrier in this use. You will need to sort that cable, don’t pinch it under the boards. Best in a drilled hole at joist centre, this avoids weakening the joist and the risk of nailing into the cable.

 

[Popshw]

Am I likely to incur any issues with condensation forming between the plasterboard and the area between the joists?

 

[Old.bodger]

Tell us more, is this an integral garage that you are converting?

 

[Popshw]

Stand alone garage, a 'cosmetic refresh' on current setup, nothing major

 

[Old.bodger]

I think damp unlikely in this set up. Firstly if well sealed from the room below any moist air won’t get into the void. You are not planning to heat the space so not increasing the moisture carrying ability of the workshop space air in relation to the void or the room above.
I’m sure someone with more building experience than mine will be along to offer advice, but I would proceed as above. My thinking was mostly ‘fire protection’ from what could be considered ‘habitable space’ above.

 

[mikej460]

Yes you should insulate between the roof covering and the ceiling - install as much as you can and can afford, and then fix a vapour barrier over the insulated rafters before you fix the plasterboard. This will prevent condensation.

Capital Valley Plastics Ltd Vapour Barrier Green 300ga 20 x 2.5m | Membranes & Barriers | Screwfix.com

 

[Old.bodger]

It’s not a roof void - there is a room above.

 

[mikej460]

Same applies as the above room is unheated and rarely used so safe to assume it will be colder.

 

[Steve_Scott]

Am I likely to incur any issues with condensation forming between the plasterboard and the area between the joists?

An architect once told me… “think insulation, think condensation, think ventilation”.
In this application you are removing the inherently ventilated space and likely reducing the temperature too (meaning it will hold less vapour). I wouldn’t have thought you’ll need vapour barriers and the like but it wouldn’t hurt to ventilate the space to allow it to breathe.

what’s the roof construction?

 

[Popshw]

Ceiling construction in room above is a form of chipboard by the looks of it as pictured below.
How would you go about ventilating the space, joists are at 400mm centres, would each section require ventilation.

 

[RichardG]

Too be honest if you want to class the space above as living space then for peace of mind I would treat it as an integral garage and would suggest insulation and a fire-boarded ceiling.