EWI detail roof with concrete ring

[Obi_wan]

I am Renovating and extending a 1930 cavity wall bungalow. I have plans but they never included EWI and I am looking for advice as will need to DIY to make it affordable. The roof has a concrete pour ring around the top of the wall giving a 100mm overhang. I planned to place 100mm eps on the walls. I started thinking this might create a cold bridge around the roof perimeter. Any thoughts?

 

 

 

 

 

 

[Iceverge]

Yes you're right. 

 

Can you budget to create a bellcast in the roof to overhang the wall further? 

[Obi_wan]

I googled bellcast as wasn’t familiar with it. So it looks like the roof would overhang the ring but not sure how this would change the cold bridge, unless the underside of the roof was also insulated. I might have misunderstood. 

 

I am adding dormers to the roof so it is planned to be completely replaced. I wondered if I used 150mm eps on the wall then a band of 50mm where the concrete ring is. This would remove any overhang. Obviously less insulation over the concrete ring but I might have to compromise from the perfect arrangement. Although this might mean the roof details need redesigned.