Sealing between shed roof and top plate

In the process of rebuilding a shed roof (interior, not a shed) with 2x8 rafters and R19 insulation. The soffits will be vented and the top of the roof is vented.

I'm trying to figure out how to seal the space between the bottom of the ceiling insulation and the top plate of the wall. Right now, with the insulation just laying there, there's a small gap or not very good insulation along the top plate.

My plan is to install 2x6 blocking between the rafters at the plate. This would create a place to foam-seal the edges and insulate right up to the block. There would still be 2" above for venting/airflow.

Is there a better solution that I'm not considering?

 

This is often a good spot for an inch or two of spray foam. It provides decent r-value for the thickness and does a good job of air sealing a difficult area.

 

Carbide, I can't picture how to 'interface' the spray foam to the batt insulation. The R19 does a fine job insulating from the roof to the ceiling, but the paper on the insulation is just sitting against the top plate - so there's a tiny little space for the cold air to come in through the soffit vent, under the insulation.

I could maybe caulk (glue) the paper to the top plate, then spray foam both sides to seal... ?

 

Sounds like the R19 extends over the top of the plate. You could peel the paper back a bit and staple, glue or tape it to the side of the plate. Or just tape the joint from side of plate to bottom of R19 paper (L shape joint.j