On 29/01/2021 08:37, Derek wrote:
When I moved into my house in 1975 all the ceilings were done with
polystyrene type materia.It was about the same width as a roll of
wallpaper and must have came in rolls. When you look up at it looks
like all the pieces of a jigsaw puzzle and it is very hard to paint
if ceiling gets dirty from smoke. Does anyone know the name of this
material? I would like to remove it but am afraid to start . Has
anyone ever removed this and is it hard to remove. There is also
polystyrene? coving round the walls as well.

It is almost certainly expanded polystyrene and at that vintage entirely
without any kind of fire inhibitor in it. Removing it is sensible.

It has almost no physical strength and will shed small spheres
everywhere at the slightest provocation.
You will find out why they covered the ceiling with it afterwards
probably loads of cracks in the old plaster. Replastering a ceiling well
is a job for experts - DIY amateurs will struggle to make it stay up.

--
Regards,
Martin Brown