On an outside mount shade with valance, why is the valance wider that the actual shade?
On an outside mount shade with valance, we provide returns on the sides of the valance, made out of the same fabric as the shade and valance. The returns conceal the sides of the hardware and give the shade a finished look. Returns are not necessary on an inside mount shade. We have to allow some extra width for the valance returns. We also have to allow some space for clearance between the shade and the valance so the shade can be raised and lowered smoothly without hitting the valance. Because of these factors, we make the valance slightly wider than the shade. The actual allowance varies according to the fabric used.
