My house has a brick outer wall and a aerated block inner wall. The inner wall is one block taller than the outer wall (maybe 8 inches?) and the roof structure rests on the inner wall. The soffit rests on the top of the outer wall and has air grills in it. The roof slopes down outside the wall line to meet the soffit. I do not know whether this is common or weird. It seems a bit strange to call the space outside the inner wall, above the soffit and below the roof the eaves but maybe thats what it is.
The gap between the inner and outer walls is insulated but this stops at the top of the outer wall. The loft is insulated reasonably well but this leaves the outer side of the top block of the inner wall open to the air coming in through the soffit, that is at outside temperature.
We therefore have a warmish ceiling (insulated), warmish lower walls (insulated) but a band of cold blocks around the top of the upstairs rooms. In the bathroom this attracts condensation like mad and the damp causes some mold.
The space between the wallplate and the underside of the roof is very narrow and if I carry the insulation over the wall plate and down to the soffit, I am liable to block the airflow into the loft from the soffit space. That same narrowness makes it very hard to even see into that space and insulation done that way would have gaps where the rafters prevent the loft insulation going. The only way I can think of getting in there would be to remove tiles and battens and tile underlay and use polystyrene blocks.
Is there a standard, easy way to insulate the outside of those top blocks?