The Natural Philosopher wrote:
pm wrote:

marvelus wrote:

On Sat, 07 Oct 2006 17:15:10 +0100, pm
wrote:


The Natural Philosopher wrote:



The real issue is the circumference of the hole in the
plasterboard. Or in fact the one side of it that takes the weight

This usually exceeds the compression strength of the plasterboard,
and the hole gradually enlarges as a result.

Tiling over locally increases the strength as the tile does the
supporting, and the tile spreads the load to the board via the tile
cement.. That works, as also does gluing a slab of wood OVER the
plasterboard. But no fixing that relies on a cylinder of small
diameter in plasterboard can take much weight.


The area is half tiled (the bottom half) and next year this will be
coming off and the whole lot tiled.
I can't locate any studs at all by tapping. It is a fairly narrow
wall (only just wide enough for a 600mm towel rail) so perhaps the
studs are right at the ends.

Opinion seems to be divided about the effectiveness of the
plasterboard fittings. Seeing as it will be tiled next year I might
give them a go. If it goes T/U you can say "I told you so!"



Like a door most of the weight is taken at the top so at least put in
a noggin there where you now have access. You'll get away with the
other fittings mentioned lower down.

If it falls off the wall you get a leak and maybe flood the place.



OK, I've thought about the responses and after getting some hollow
wall anchors and looking at their use I am now considering putting a
nogging in as I am not comfortable with the wall anchors.

I've not put in noggings before so I would appreciate some advice.

The wall is 90cm wide, one end is 10cm masonry (I think - it is the
edge of where a door used to be. All the original internal walls are
masonry). 80cm is plasterboard. The other end is the architrave for
the door.

I can't locate any studs by tapping, it all sounds the same to me
except where the masonry is and perhaps 1" from the architrave. So
assuming I have to cut out the whole width of the PB, what is the best
technique? Drill through then use a wood saw/pad saw/jigsaw? The
plasterboard is quite thick, about an inch (could be 2 x 12.5mm boards?)


Best I found was a small seratted edge kitchen knofe - 'kitchen devil' IIRC

How wide should the nogging be? How is the nogging fixed to the studs
- nail or screw in at an angle?


It really depends on how string you want it.

I like to cut a ply or MDF strip and attach to stubs of 1 1/2 x 1
battens screwed into the studs. Nailing on a skimmed wall usuallly
'starts' the nail- or screw- heads that were used to attach the
plasterboard


Others simply nail diagonally into the studs, but I think if you can get
a drill or screwdriver into the gaps between the studs, using battens as
supports is better.


Once the nogging is in, do I just plaster over after priming the wood
or should I put the cut-out plasterboard back and fill the gaps?


Put the plasterboard back but make it a little below the rest. That
gives you an easy set of edges to skim to. I generally try and set the
mounting plate/noggin back by about 2-3mm.

Done as you suggested and so far (cutting + battens + some 18mm planed
wood I had spare) has gone like a dream. Excellent tip about setting
back a couple of mm.

Last Q:
When putting the plasterboard back against the wood noggin is it best to
screw, nail or Gripfill? There are 2 sheets of plasterboard back-to-back
and they are not joined together, if this makes a difference.

Thanks again

Pete