fitting a new pvcu cladding bathroom ceiling

[zebraplec]

Hi, I have just taken down the polistyrene? tiles from my small (200 x 200 cm ) bathroom ceiling, and found that the ceiling (plasterboard) is very uneven.
I am thinking of putting up some battens and then plastic t & g ceiling that I have seen at Wickes and B & Q.
The questions are:
1. how do I find the level to mark on the walls?
2. what size of battens do you recomend?
3. the walls are not square, so each wall is a differant size, so do I screw to the wall anyhow, or do I make the 'frame' square.
4. where the battens do not touch the pasterboard ceiling do I 'pack it off'?
Hope someone can help please.

 

[foxhole]

Why is ceiling uneven, are timbers moving , unsecure above plasterboad? it would be folly to hide such problems, if the timbers are ok then replacing plasterboard would be cheaper and easier to do.Lowering a bathroom ceiling is not a good idea unless you have really high ceiling.

 

[zebraplec]

Foxhole, thanks for your reply, however the wood (joist) is okay, the reason the ceiling is unlevel because of two reasons.
1. the plasterboard that was put in when the house was built slopes from one side to the other, which is not to bad, I suppose.
2. my house is a bungalow and we use to store lots of items 'up-in -the-loft' this must have cause the ceiling to sag in certain points.
So, I could pull the ceiling plasterboard down, but I would only end up putting battens on top of the new ceiling because my wife wants a UPVC type of ceiling.
I have worked out that I would only loose 18mm of height for the batten and 10mm for the UPVC, so a total of 30mm max, 3cm, which is not to bad.[/code]

 

[foxhole]

You will really struggle to level a ceiling with thin batten.The pvc ceiling will attract dust due to static and be difficult to clean in the grooves.