here. If you are interested in hanging curtains underneath, I suggest reading her blog post. As this is a window above my bathtub, I went for just the cornice.
First, I started off with one of those 11" x 8 feet pieces of MDF board. You can see mine is already primed, but there is no need for that. For some reason my husband wanted that one. And when he is helping me with a project, I rarely contradict him. (yeah right!) OK, the truth is I sent him to Lowes and that is what he came back with, not seeing my vision yet. This board was only about $10. Anyway, I measured the width of my window and added 6 inches (3 inches to each side.) That is the long piece. As for the 2 sides, I cut them 5 inches each. Now I borrowed a saw from my neighbor because we were doing the floor, but they will cut for you for free at Lowes! Just bring the measurements with you when you purchase the MDF. I bought 4 "L" Brackets and screwed the sides onto the long piece.
And here you go:
And just in case you wondered, I recovered that stool! Doesn't it look great?