Where would we be without expanding foam?

Now I know why lots of passive houses have nice simple roofs and gable ends - it's so much easier.

Here, we have the insulation above the rafters (hiding beneath the blue felt), meeting up with the first layer of wall insulation, and overlapped by the second layer of wall insulation. And any spare space between there and the last counterbatten is filled with expanding foam.

Helps with air tightness too.

Excess foam is trimmed off and that's it.