On 26/11/2015 08:32, harry wrote:
Dents.
Fill in with plaster& let set.
Gaps
As above Pus maybe a bit of scrim (woven tape) to prevent cracking.

Then plaster skim as normal.

Or use polyfilla, takes longer to go off = more time to mess about with it.

Foam is totally unsuitable unless gaps are really big.
If so, fill gap, let set& trim off with bread knife.

To answer some questions from previous posts:

The`dents` are a couple of holes in the plasterboard from ripping off
tiles, the state of the plasterboard is generally ok, I planned to fill
the holes with foam then a thin skim with one coat over the complete
partition, I will be retiling it. Partition is 5 x 4 feet.
`Gaps`: where I have taken off a couple of sheets of badly damaged
plasterboard there is a gap about 3 cms wide between the floorboards and
the wooden wall frame (studs) This gap leads to the underfloor ground area.
The reason I earlier asked about using the foam over a period is that I
will proably discover more `damage` as I progress.