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.

Artie wrote:
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.

FWIW, the vinyl basement windows I used a couple of years ago didn't
need any framing. They were not two section sliding type, though,
rather the top opening type. I installed them by building up the
opening to the exact window size with mortar and brick. The top piece
(wood) I left until the mortar surround around the unit had set. It was
easy to make nice slopes inside and out for appearance and shedding
water. Slicing brick pieces to size was readily done with a modest
priced diamond blade in my circular saw. The vinyl to mortar bond is
quite good and still looks perfect today. HTH.

Joe