Dave Page wrote:
Phil L wrote:
* Is it possible to screw entirely new plasterboard over the
sagging plaster, and the hole, and the existing ceiling? This seems
perfectly possible from reading
http://www.diyfaq.org.uk/miscellaneous.html#repairing and similar,
but the problem is that the existing ceiling has stippled plaster.
It doesn't matter if it's stippled or not, plasterboard screws come
in a few sizes and anything less than 3 inches is a POP*
OK, so would I want to screw the new plasterboard directly onto the
stippled ceiling, or use spacers to leave a gap, or try to file off
the stippling somehow before screwing new board down?
Dave
Unless it's scalloped (really deep furrows of plaster like olde worlde) then
you don't need to do anything to the stipple.
Find the joists and mark on the wall with a pencil the centre of each joist
(sometimes they are not all evenly spaced, most of them are set at 16 inch,
but if the joiner that day had 1 joist too many or not enough, they could be
spaced differently.
Once you've got a pencil mark on each wall, get someone to hold a piece of
timber up and strike a line along, either with a pencil or use a chalk line,
so that the ceiling has a clear line where each joist is.
Don't use spacers nor anything else, 3 inch plasterboard screws (watch out,
they are *surgically* sharp) and a decent cordless driver are all you need.
If you are boarding it for someone else, don't leave any gaps between
boards, also they must be 'staggered' like this :
___________________________________________
I
I
I
HALF I
IFULL BOARD
I
_____________________I______________________
I
I
FULL BOARD
I
I
I
I
__________________________________________ I
and so on..
and *not* done like a chess board, like this:
___________________________________________
I
I
FULL BOARD
I
I
I
I
__________________________________________ I
___________________________________________
I
I
FULL BOARD
I
I
I
I
__________________________________________ I
The dotted lines in the above samples are the short ends of 6X3
plasterboards, and you should have the short edges meeting on a joist, don't
have the long edges meeting at the joists, otherwise you will end up
trimming the length rather than the width when you get a tight fit and this
weakens the board (the edge with paper all round it) causing it to crumble
and you don't get a good fixing.
HTH
(If the above diagrams don't come out too clear in this post, I'll do a jpeg
and put it up somewhere)