Plaster Boarding onto tongue and groove!!

[pdhshy]

Hi
I have a house were all the upstairs ceillings are covered in tongue and groove boarding. I wood like to plaster the ceillings and I don't know whether I can just screw the plasterboard straight onto the tongue and groove (making sure I locate the joists) or whether I will need to put up some thin battens to leave a small gap (25mmish)!! I was also thinking of using a thermal backed board, but will I need one with a moisture barrier?? Hope someone can help.
Many Thanks
Pdhshy

 

[dave1953]

personally I would rip it all out and plasterboard onto existing beams.Thats a big fire risk to leave the t & g in place unless you use firecheck p/board over it.I also think to use battens over the t & g and p/boarding may lead to cold spot condensation problems in the long run.

 

[noseall]

it will make no difference as to whether you leave the t&g in place or remove it.

what is more important is that you use foil backed plasterboards. these can sit hard against the t&g.

most ceiling joists are made of wood.