Place the straight edge at this measurement. Fold the valance fabric up and over the straight edge. The right side of the fabric is now on the surface, and you now have a 2-fold valance. Align the top edges and re-position the pins to include all 4 layers. Sew across the top of the valance 3/4 inch from the raw edges.lace the straight edge at this measurement. Fold the valance fabric up and over the straight edge. The right side of the fabric is now on the surface, and you now have a 2-fold valance. Align the top edges and re-position the pins to include all 4 layers. Sew across the top of the valance 3/4 inch from the raw edges.