I am re-doing the siding, doors, and windows on my 3000 sqft, 1960 1-1/2 story rancher. I am pretty sure somewhere between 20-30% of the sheathing will need to be replaced and at bare minimum need new WBR applied to the rest of the house. I have already air sealed the attics, installed an 18kw solar array, and updated all my mechanicals. I am in zone 4 and while we don’t get extreme cold seasons, I want to strive to insulate the house as much as possible and take advantage of the solar energy. The house currently is 2×4 framing with fiberglass r-15 batts. My plan is to update the windows to triple pane, put in insulated doors, and add 2″ polyiso (following GBA 9-00401), and add furring strips before installing siding. I think this plan will get me about R-28 and will work for about 50% of the house, however I have four gambrel peaks, where the current siding / fascia runs up to the roof shingles where there is no overhang. If I add the polyiso to the walls, the siding will stick out past the roof, and would be exposed the elements.

I originally thought I would fabricate an 8-12″ overhang for these roofs and add shingles. The issue a roofer friend of mine brought up was if I wanted to add an overhang, I would have to re-shingle the majority of the roof to get the shingles aligned. My second thought is to fabricate a 4-6″ overhang,  bend up a wide drip edge that matches the color of the shingles and stuff it under the shingles, leaving a 4-6″ wide band of aluminum on the edge of the roofs. While I think it would work, it is not something I have seen anyone do before.

Has anyone ever ran into this situation, where adding exterior insulation sticks out past the roof? If so what did you do?