Parapet Wall Coping Cap - Copper, Aluminum, Radius and More
Parapet Wall Cap available in any size or material. Radius or straight. We match any profile. Copper, Aluminum, Steel, Freedom Gray, LCC and more.
www.riversidesheetmetal.net
Naturally this would be placed under the sill not on top. You also don't need the lip on the inside actually it would be better if it wasn't. You would better with two pieces since the block wall is probably not perfectly straight.
I was better explaining this in the field with scrap paper than typing it here.