Our previously finished basement was a combination of drywall and wood paneling over concrete block with no insulation. We removed the drywall and paneling over the block and intend on adding foam insulation and studding out a wall, as described here.
The basement has an existing window that was recently installed. As near as we can tell, the window was installed over the existing drywall and window sill.
This existing sill and drywall (see below) will not extend to meet the addition of the 2" insulation and studded wall. Because the window sits on the existing sill, I don't believe I can replace the sill or drywall without first removing the window.
Should I bite the bullet and remove the window, or is it acceptable to install a new, longer sill over the existing one?
Placing new drywall and sill over the existing seems like the easiest path, but does it create a nightmare for the next owner when they go to replace the window?
Is there a better way?