In article ,
"a" writes:
Having had half the kitchen plastered (ceiling and largest wall) - the
plaster has "gone missing" and left the job half done. We need it finishing
pretty quickly but it is tricky getting anyone to do the job soon or at a
reasonable price. There are no big walls left, the biggest single area is
about 3' wide x 7' high, a few smaller bits around a box type window, and
two small bits of ceiling above the sink and where a wall was knocked
through. Some is already plasterboarded, I dont think nailing/screwing the
rest of the plasterboard on is a problem (he left a bag of bonding coat for
one section of wall - might have a go with that too as he probaly hasnt left
enough board to do the whole thing). So once it is all boarded, it is just a
matter of skimming it all. I can see that might be tricky on a big wall, but
on relatively smaller sections that can probably be done one at a time
surely it isnt that hard to get an even coat? I do fancy having a go if I
think there is a chance I can do it, but have a few questions...

1) Consistency - I keep reading the plaster should be "creamy" but does that
mean thick cream? Are we looking at something that should drip off the
trowel? I guess it must have to have a certain thickness or when you
transfer from mixing bucket to board it will spread out on drip off the
edge!

If you're not careful, it does!
As a rough guide, scratch coat plaster should be just thick
enough that it stays on the trowel when held vertically, but
slides off if you give the trowel a small vertical movement
to break the friction. Finish coat should slide off a vertical
trowel.

2) Do I need to put corner beads on *all* external corners, or just
vulnerable ones?

It makes it much easier to plaster.

3) There is a kitchen sink/worktop/base unit already in place that needs to
be plastered up to. Should you really plaster right up to the worktop
surface and base unit sides, or somehow stop just short and then maybe put a
bead of silicone at the join?

Not sure. I think I would plaster right up to the edge initially
as it will be difficult not to, and then when the plaster has
started going off, but before it's rock hard, use a knife to
remove a thin strip. Only when the wall has completely dried
should you fill this with silicone or some other flexible filler.

4) When skimming over an existing skim coat that has had several layers of
wallpaper on - is it imperative to get every last bit of paper off or can
you plaster over it (I am guessing if you can plaster over paper joining
tape etc then you can go over those stubborn bits of paper that get left
behind?)

I guess if the worst happens it can always be scraped off )

You can skim over anything, providing the surface isn't in
danger of coming loose. The problem is that the surface you
skim needs to be flat. Scratches, dents, holes, etc which are
smaller than the length of the trowel don't matter, but bumps
may well show on the finished plasterwork if they are significant
in profile.

--
Andrew Gabriel
Consultant Software Engineer