I want to remove my old basement windows and replace them with vinyl
slider types. The old ones are steel frame, hopper type and the
concrete foundation is poured around the steel frames (buck) on 3 sides
and the top is tight to the wood sill. The concrete is sloped on both
sides and the bottom, inside and out, and after I remove the old frames
I will have a channel in the concrete on 3 sides. I want to frame out
the rough opening for the windows with pressure treated lumber but how
would you do it with the channel and all those angles from the slopes
in the concrete? Any help is appreciated.