Insulating my cellar ceiling but what material to use

[AMCLS1]

So on Friday I had my loft insulated, a difficult job as we have some suspended ceilings which have been installed over old lathe and plaster vaulted ceilings so access is extremely difficult. As they were leaving after successfully completing the job (adding 300mm of Knauf loft roll) I asked the boss to look at our cellar which is a traditional lathe and plaster celling with what looks to be joists of around 150mm, if not slightly more.

My plan is to cut away the old lathe and plaster in the cellar, carefully, to avoid the absolute breaking loose of hell that comes along with L&P and then check and vac all joists, clean them up so we can install insulation.

Questions:

1. He said that they would use the same roll that they installed in the loft. Would this be suitable for between joists in a cellar?
2. He stated that they would hold it in place with netting attached to the joists. Would it not need some form of vapour membrane or would the netting do that job?
3. What do we do when we get to the stone walls of the property? Do we need some sort of barrier between the insulation and the stone wall?

The cellar is relatively dry and it has good airflow as it has old single pane windows, which are draughty, so I intend to replace these with more modern units but I do see them as a bit of a positive since they allow air to flow in the space.

I just want to make sure that I am 100% clued up so that I can make some informed decisions.

Couple of pics attached, you can see where some L&P was chopped out when we installed the new boiler and ran some new heating pipes to other parts of the house.

Thanks in advance.

 

[Wayners]

What about putting in a ceiling and adding insulation behind.

I'm thinking about trapping rock wool because of the glass fibres that get in the air

 

[StephenStephen]

Writing as an amateur here...

Are you wanting to stop heat going from the room above into the cellar?
If so, I would think that draughtproofing between the cellar and the rooms above would be the priority, particularly if there's an internal door down into the cellar - good seals round the access door and a draughtproof seal between any cellar ceiling insulation and the floor above.
I think removing the lath and plaster is the opposite of what would be helpful! If I were you I'd repair the holes in it and insulate below it

I agree with you about the windows - they ain't broke so don't fix them. You could end up with a damper cellar.

I suppose one way of thinking about it is that the cellar is a bit like a cold loft.