Internal wall insulation - bedrooms / solid stone walls

[RichardL]

Hi - looking for pointers:

I have a couple of rooms in a solid stone walls part of the house with 2x and 3x external walls respectively, one has the inside of the chimney stack.
I can keep them warm if I push in enough energy - but overnight in winter they drop back to 12ºC at the drop of a hat.

Room floor sizes ~3m x 3m
 

I have external insulation elsewhere but it's not possible/desirable for this part of the house so thinking internal insulation.
Ceilings above to loft are insulated.

Question
Is IWI a potential DIY job - battens/insulation materials followed by a professional to skim/plaster?
Drilling/cutting boards etc I can do.

Can anyone recommend any products to shortlist - especially thin as possible options, any build up needs to be <10cm per wall or I'm stealing a lot of internal space.

Many thanks;

[jayc89]

How thick are the walls and what's on the other side of them? Exposed brickwork, render (lime or cement), etc?

Typically, stone walls are quite good at retaining heat, albeit not to the same level of modern properties, a room shouldn't lose that much heat, unless there are other causes; air leakage, dampness etc. It might be worth discounting those things first, before decided on an appropriate insulation method. 

[Redbeard]

I like to use rigid wood-fibre on a lime parge (air-tightness) coat. It's fairly DIY if you are quite handy and good at attention to detail.

[RichardL]

8 hours ago, jayc89 said:

How thick are the walls and what's on the other side of them? Exposed brickwork, render (lime or cement),

Around 1' -18" thick..  outside - stone facing cement/roughcast render, from what I saw when re-tiling I suspect rubble infill.
The bedrooms sit half in the roof space, both have a gable end wall / end of the house.
 

[RichardL]

8 hours ago, jayc89 said:

air leakage, dampness

Certainly air leakage - its not obviously drafty inside, but in the floor space and loft space theres no issue with ventilation - eaves seem to let air through to both areas relatively freely.