Tyvek and windows plywood boxes – GreenBuildingAdvisor

I’m making an assumption that your window box is being installed to move the window rough opening out past a layer of continuous exterior insulation.

This article shows how I detailed this connection. https://www.greenbuildingadvisor.com/article/a-practical-perfect-wall

In this project, we used a self-adhered WRB, which was installed first. The same principles would apply to a mechanically attached WRB (Tyvek). I don’t recommend folding the WRB into the rough opening. I prefer the 2″ cutback method which is shown in the article. Our windows had nail flanges and were installed as “outies”. We used 2x material for the window box or window buck, but the details will be similar.

There are other ways to do this, all will probably end up requiring a tape origami to correctly connect the WRB and air barrier to the window box or buck.