How to retrofit insulation at intersection of cavity and ceiling

[sam]

My 1950s block-cavity-block two story house had EPS beads injected into the cavity. I've recently discovered that the outer wall is c. 400mm shorter than the inner wall and the cavity is open to the eaves void and the loft. This means that the top of the wall is not insulated. Is this common? Any suggestions for insulating this area? The gap between the inner wall and the roof is small (c. 50mm), meaning it's hard to access this area.

[Spreadsheetman]

Tricky one, that’s a killer cold bridge.
 

My chalet bungalow had something similar, but the difference was less than a block height and I had the ceilings down so I was able to plug the top of the cavity and insulate the inner block at the same time from inside with sections from 100mm semi-rigid rockwool batts. I used short batten sections to hold the rockwool away from the roof and ensure there was a ventilation gap.

 

Interesting to see what people suggest.

[RobLe]

Our house, 1963 build, didn’t have cavity closers either.  As part of the Ewi process, I had scaffolding up.  I took up the bottom two rows of concrete tiles, folded up the membrane, easy access then to fix it how I liked (glued insulation in place with expanding foam glue).

[Iceverge]

You could just fill up the fascia and soffit with EPs beads, right up to join the attic insulation. Then put some slate vents up higher in the roof to ensure the cold loft space remains ventilated. 

[MikeGrahamT21]

I’ve got this job on my radar for this year, years ago I blindly tried to get insulation in right place but I’m almost sure I missed bits I couldn’t reach.

 

will photograph and document it on my blog on here

[sam]

Thanks for the suggestions. I came to discover the issue as I intended to improve the ventilation into the attic, so agree that I need to address these together.