Roof Insulation (not loft, not flat roof)

[mondeoman]

The roof over our stairwell and hallway runs from the roofline of the main shell down to ground floor level, and this is the one part of the house that is always cold.

I've had a look and there is no insulation at all in it: the loft itself is insulated, but the sloping roof (about 10m2) is simple lathe and plaster ceiling, joist space, tiles.

Whats the best way to insulate this - tiles off and insulation, then re-tile, or ceiling down, insulate and new plasterboard cceiling? - or a MUCH bigger radiator and live with the heat loss??

[mondeoman]

That'll be another summer job for me then.

I was thinking of just pouring polystyrene beads in from the loft - could be fun doing that

[mondeoman]

Given that the tiles aren't exactly air tight, why bother with an air gap, and not just fill the void (its about 3") totally?

[mondeoman]

No felt anywhere to be seen. This was built pre-war, so its very basic construction - rafters, lathes, tiles (and some evidence of cement): it is literally ceiling paper, lathe and plaster ceiling, rafter, lathes, tiles.