On Sat, 20 Sep 2008 19:10:02 GMT, "The Medway Handyman"
wrote:

robert wrote:
We have a ceiling with a smooth emulsion finish, unfortunately long
cracks appear in the course of every few years - one along the line
of a plasterboard joint and two others that are not in line with the
plasterboards.

I have repaired them with a d-i-y filler (made up polyfilla or
similar) in the past but have decided to do something that will
hopefully be a bit more permanent this time.

I have raked the cracks out - the depth appears to be around 10mm and
was wondering about applying a gap filling adhesive (No more nails?)
in the apex of the crack and finishing it off with either a light
weight sandable filler which I imagine will give the finish most
likely to blend in once painted or possibly caulk which I understand
has the benefit of being slightly flexible but may not blend in as
well as the sandable filler.

I would be grateful for any suggestions or comments.

Caulk is flexible enough to withstand the movement without cracking - but
very difficult to sand, so you have to get it smooth when applying.

I'd agree about the sanding attributes of Decorators caulk . But how
about filling to some degree with some sort of filler then using
plasterboard jointing cement ( Gyproc is one make) to complete and
that gives a very smooth finish