DIY Doctor UK DIY Forums

Hi, need a little help with my basement conversion.

Got the cavity drain membrane in and floor is all sorted (50mm kingspan and chipboard on top)

Am about to start drylining the place and I've never done it before.


Ceiling:


My first questions are about the ceiling; I'm thinking of double boarding with 12.5mm boards.

1. Should I use tapered or straight edge boards?
2. Do I need to tape and fill the joints on first layer of boards before putting the second layer up?
3. When I'm putting up the second lot of boards do I stagger the joints in relation to the first set or do I just put them up straight over the first set?
4. Would 40mm screws for the first boards and 70mm for the second lot be appropriate?

Thanks for your help!

James

Plasterboard is used because it provides a 30 minute fire break.
There is no point in using thick or two layers unless you intend to keep something that is inflammable down there.
As warm air rises you may find it helpful to fix a two or three inch thick layer of polystyrene across the ceiling before you plasterboard.
This will slow the movement of heat from the basement and help to keep your feet warm.

Perry525 wrote:Plasterboard is used because it provides a 30 minute fire break.
There is no point in using thick or two layers unless you intend to keep something that is inflammable down there.
As warm air rises you may find it helpful to fix a two or three inch thick layer of polystyrene across the ceiling before you plasterboard.
This will slow the movement of heat from the basement and help to keep your feet warm.

ALWAYS use double layer plaster boarding when lining a ceiling where a living space is above. It is not worth the risk of reducing your chances of escaping in a fire.
Single layer plasterboard is said to give you 30 minutes of fire retardness but I would always advise using 2 staggered layers to be safe.

Also NEVER use polystyrene as a ceiling insulator. Polystyrene is extremely flammable and releases toxic fumes when alight. I understand that you are saying that the polystyrene would be behind plasterboard but it really is not worth the risk. Regulations are in place for safety reasons and I would never advise on breaching them.
A safer and better alternative is rock wool fibre glass insulation which can be packed between the joists for thermal, sound and fire insulation.