In message <3F04C850.1D5044D@nf.sympatico.ca>, Terry 
<tsanford@nf.sympatico.ca> writes
>David wrote:
>>
>> "James W" <jameswilson_uk@hotmail.com> wrote in message
>> news:75dc8650.0307031436.1e9c8a37@posting.google.com...
>> > I have plasterboarded my ceiling with the 4 or 5 mm stuff. It is
>> > screwed onto battons I had attached to the existing ceiling. It is
>> > fine in most places, however at its worst parts you can push it in and
>> > it bends in. Will I need to redo the whole thing with the thicker
>> > plasterboard? Or will the skim coat a plasterer will apply be OK? The
>> > ceiling is fairly high and in a bedroom so I dont expect many people
>> > to be pushing and prodding it.
>> >
>> > Thanks in advance
>> >
>> > James
>>
>> Standard is 9 mm for ceilings
>>
>> D
>
>Learn something all the time! Didn't even know one could get 4-5
>mm plasterboard (roughly quarter inch?).

Yep, bit less in fact.

Though I didn't know PB that thin was available either, I've never ever 
seen it.

Or do you mean something else James?

> Thirty years ago, here,
>the most commonly used (residentially) was three eighths (9mm).
>Now half inch (12mm) is standard for just about everything, cos
>of 'fire rating'!

12 mm is pretty common now, though so is 9.5 mm as well.

To answer James, no if it moves then plastering won't help. I would say 
that at the very least you need to overboard with 9.5mm board.

-- 
Chris French, Leeds