Is it worth the effort?

[Bluebells]

at one end of our house leading off the kitchen is a utility / study room above which is the main bedroom. Both rooms are 6 m x 6 m, the attic above the bedroom is very well insulated, there is a fair size radiator in both rooms. All windows and doors both up and down are double glazed. Below the utlity is a cellar accessed from outside, this has had its ceiling lagged with the silver foil insulation stuff. In winter this part of the house remains stubournly cold. Cant really see what else i can do to improve this situation except use rolls of insulation in the cellar between the ceiling beams and then use attic floor covering to hold in place, the cellar is lovely and dry i might add. Do you think this is worth it and does the tin foil layer thing compromise the second insulation roll or vise versa, your thoughts please!!

[Théière]

Bluebells, you have not said what your walls are made of or if any of them are north facing.

I do not believe from your explanantion that insulation between the joists will achieve much, insulating the walls may achieve a lot more in terms of heat loss. If your wall are attractive stone then that is the sacrifce you may have to make or install a much bigger source of heat.

[BIG MAC]

The cave is designed to be cold is it not?

As Teapot says you have walls which will absorb heat at quite a rate. so to make things better in the rooms above you would likely need to ensure that they are well isolated from the cold cellar.

I believe that multi layer insulation packed between joists then Insulating plasterboard below that will make a considerable difference however noting that its a utility room above, a water leak /spill may well cause issues.

An alternative may be to use 'Cellotex' type rigid insulation cut tight to fit between joists having first wrapeed the joists themselves in a coupleof layers of  'foil bubble wrap' then fasten a couple of roofing battens either side on the joists to hold the plot in pace. This would be water resistant and easily removed but would carry no fire protection whereas the pasterboard would. My only reservation being that polystyrene on the back of plasterboard may eventually catch fire and produce nasty fumes, How often  do cellars catch fore though?..........questions.... questions!

[Bluebells]

sorry, yes old wide stone walls throughout i am afraid, this is the only bit of the house that goes cold really and i put that down to the cellar below so it would seem the only solution apart from extra heating is too add extra insulation from below, thanks for the replies

[Bluebells]

in addition yes they are dressed stone, the rear house wall is north facing and has a set of double glazed french doors down stairs and no windows upstairs