While the subcontractors are inside, Neil has moved to the outside. He will be adding 1-1/2" of rigid insulation on the exterior of the building...over top of our weather barrier which covers our 1/2" plywood sheathing. Once the insulation is applied, he will then install 3/4" plywood battens vertically, aligned with the studs in the wall. This will create a drainage plane behind the siding. We are using 2 different types of siding. 1x6 cedar beveled siding that we are having pre-stained black and 8" exposure James hardi lap siding which will be painted an undecided grey.
Because we are adding more thickness to the wall, we had to rethink our exterior trim. Originally we were wanting a 3-1/2" wide trim that would be picture framed around the window, but after mocking it, we came to re-evaluate this due to the multiple 12 steps to building it out versus 5 for the 2x on end. 12 x 34 window groupings equal a painfully slow process. So we decided we liked the more streamlined look.
You can see all the extra blocking needed in this side shot.
We also briefly looked at adding a stepped trim piece around the frame, but decided against it's fussiness.
We have tried to minimize the fan vent locations and while we do not have individual exhaust fans for our main part of the house, we still have them for the apartment portion. For every hole coming through from the inside to the outside, Neil has boxed it out and flashed it like below. All of the vents, hosebibs and exterior electrical outlets receive this treatment.