1906 Foursquare getting 2 layers of 1.5″ GPS exterior insulation. This is going over the top of house wrap that I’m considering the air barrier and will cover the original shiplap sheathing.

The roof is vented with baffles and insulated with spray foam. I intend to seal that SPF to the house wrap to complete the air barrier. For the thermal layer, I need to bridge from the exposed SPF visible on the top plate to the GPS insulation. 

All this work is complicated by the horizontal soffit nailers being in the way. These nailers attach to the wall below the top plate of the wall assembly. See attached picture – this is during siding tear off and the top row of shiplap sheathing can be seen under the rosin paper. It looks like these nailers are a 1×6 and attached well below the top plate. 

I searched for an article addressing this situation but didn’t find any. Please direct me to an article if this has been addressed. 

I have a set of froth-pak lines and could spray that ~1′ width to get the air sealing and insulation continuity.  Removing all of those nailers so the house wrap and insulation can extend to the top plate will be very time consuming; must be another option. 

Thanks.

Tim