Outer leaf blockwork higher than inner leaf - Cavity closure

[Mulberry View]

This is the high end of my Car Port, 10° Monopitch roof. The inside is facing brick, 65mm cavity, medium dense concrete blockwork outer leaf. The bevelled wall plate has a DPC under it and is resin-bolted down. I didn't have the foresight to utilise a wide DPC to allow me to use it to close the cavity. The outer leaf is to continue up to the underside of the deck. I'll then attach a circa 100mm deep OSB fascia to the ends of the Posi joists for the single-ply membrane to turn down onto and with ventilation behind it.

 

 

 

Is it sufficient to attach a DPC to the inner vertical face of the DPC, then turn it over the cavity, landing on the outer leaf? I wouldn't want to lap it in by more than 20mm or so, because of course the final blocks needs to bond.

 

Any words of advice from the invaluable Buildhub experts?

[Mr Punter]

I doubt you need to close the cavity in any case, but I would look at a Rockwool sock compressed between the wall plate and the outer leaf, resting on the wall ties.