Arched windows can add interest to a room. Typically, the windows have rich wood mouldings that do not require window treatment coverings. However, this can also leave the room feeling harsh. If you want a softer look to your window, consider sewing a window treatment for arched windows. This treatment will fit inside the window casing, leaving the moulding exposed while providing soft texture and colour. A sheer or lightweight fabric will hang along the curve of your arch in a more uniform way than a heavier fabric.
Install the arch curtain rod inside the window casing. Follow the packaging directions for placement of the clips that will secure the rod in place.
Measure the length of the arched curtains. Begin at the tallest section of the rod and measure downward to the length you want the curtains to hang. Add three-and-a-half inches for the top and bottom hems. If you want your curtains to puddle on the floor, measure to the floor and add 12 inches in addition to the hems.
Cut the fabric according to your panel measurements. Stitch the fabric together with half-inch seam allowances until the panel is the width you need. Stitch a half-inch seam along the top of the curtain. This forms a narrow rod casing.
Fold the bottom edge to form a double one and one-half-inch hem. Sew with a basting stitch. Do not press. The panel will hang longer on the ends than in the middle due to the arch of the window. This helps the curtains hang better when pulled back on the sides. If your curtain will hang straight down, hang the curtains and mark a horizontal hem line straight across the length you want them to hang. Remove from the rod. Cut the curtain one and one-half inches below the line, then baste.
Insert the rod and place the rod in the clips. Hang three days, to allow the fabric to stretch or shrink. Remove the basting and adjust the hem if needed. Machine stitch the hem, press and rehang.
Many panels of fabric can be hung in one curved window. Multiple panels will create a fuller look and make the covering less transparent. Consider hanging two colours of sheer fabric in the arched windows. Arch curtain kits can be purchased at larger home improvement stores.
Narrow arched windows will not accommodate heavyweight drapery.