This portion of my garage had not been finished when I built our home in 1993. In order to insulate the attic over the garage, I had to install proper vents, or air chutes, and insulation dams. First, I removed the soffit panels from outside. Then I stapled up air chutes, full with. Then I compass cut short pieces of rigid foam to closely fit the contours of the proper vents. I caulked these to the wall sheathing and foam sealed the gaps. Later, I will continue stapling up the air chutes from inside the attic and will air seal the joint between the wall and the ceiling rock.