How is head flashing done with parge coating around basement windows?
We’re using 5″ of Roxul Comfortboard on the exterior of our foundation, so our basement windows will have plywood window bucks. We’re going to use HardieBacker board to cover and protect the Roxul, mainly around the perimeter of the foundation at grade and just below, but also around the basement windows. We will then use a product called Tuff II (readily available here locally at big box stores) for the parge coat.
I’m assuming the basement windows should have both sill flashing (which we think we have figured out), but also head flashing. For the rest of the foundation, if water finds its way between the top of the foundation and the Roxul, it can make its way down to the footings and then out, but what if it makes its way to the top of our window bucks?
I searched online for this detail, but I didn’t come up with very much. Attached are two photos that show this detail, but even though there’s head flashing present in both, it doesn’t look like there’s any gap between the flashing and the parge coat. Doesn’t this defeat the purpose of having the flashing? Should we maintain a 1/4″ gap between the HardieBacker/parge and the head flashing? Should we put insect screen in this gap? And unlike the windows in the photos, ours will be “innies”.
Does anyone know of any diagrams, photos, or videos that I could look up that show this detail? Does anyone have experience making this detail work? Any alternatives that might work?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part