Flat Roman shades look good when you want a clean-lined, no-fuss window treatment. They can be casual or formal, modern or traditional, depending on your fabric choice. Flat Roman shades typically feature wooden dowels to keep the folds rigid, but you can make them without dowels for a softer, yet still crisp look. Making flat Roman shades without dowel rods also makes the construction process simpler, while still giving you a custom, well-tailored look.
Measure the width of the sill inside the window frame for Roman shades you'll mount inside the window frame. Measure the length from the inside top of the frame to the sill. Calculate the width of outside-mounted shades by measuring from the outer edge of the window moulding to the outer edge of the other side. Measure the length from the desired mounting height to the windowsill.
Add 2 inches to the width measurement of your window for inside-mounted Roman shades, or 4 inches to the width of your window for outside-mounted shades. Add 6 inches to either length measurement.
Cut shade fabric, drapery lining material and fusible interfacing to your total width and length measurements from Step 2. Center the pattern on fabric with a print before you cut.
Pin the adhesive side of the fusible interfacing to the wrong, or non-decorative, side of the shade fabric. Press with a warm iron to fuse the interfacing to the fabric, with the interfacing facing upward. Remove the pins. Follow the interfacing manufacturer's instructions if they differ.
Pin ring tape vertically to the right side of the drapery lining material, ring side up. Pin the first two strips 2 inches in from the outside edges of the fabric. Pin a third strip in the centre of the fabric. Center additional strips between the edge and centre strips. Center additional ring tape strips between the previous ones until they're spaced 5 to 7 inches apart. Align the rings horizontally across all the strips as you pin, with the bottom ring 1/4 inch from the bottom of the shade.
Machine stitch both sides of each ring tape strip to the lining material, with the ring side facing upward. Remove the pins.
Pin the shade fabric to the lining material, right sides together. Sew the bottom and both sides together with a 1-inch seam allowance. Remove the pins. Turn the fabric right-side out. Press the edges with a warm iron, with the lining material facing upward.
Tack the rings to the shade fabric with a hand-sewing needle and thread matching the shade fabric. Start on the lining side, to keep the knot from showing from the front, and use small stitches.
Cut the 1-by-2-inch board 1/4 inch shorter than the width measurement from Step 1 for an inside-mounted shade. Cut it 2 inches wider for an outside-mounted shade. Cover the mounting board with lining material for an inside-mounted shade, or shade material for an outside-mounted shade. Secure the fabric with staples positioned at the top of the board.
Staple the top of the shade to the top of the mounting board, positioned so the hanging shade length equals the length from Step 1. Cut off any excess fabric from the top after stapling. Turn under the unsewn edge for outside-mounted shades before stapling.
Align eye screws with the ring tape strips. Screw them into the bottom of the mounting board.
Double the length from Step 2, then add the width. Cut one drapery cord per ring tape strip to that length. Lay the shade lining-side-up on a flat surface.
Knot a cord securely to the bottom ring of the leftmost ring tape strip, and thread it up through the strip's rings and the aligning eye screw. Thread the cord through the rest of the eye screws, working left to right. Repeat with the rest of the cords and ring tape strips. Knot the cords together just to the right of the rightmost eye screw. Knot the cord again near the bottom of the shade. Trim the cords to a uniform length.
Hang inside-mounted shades by screwing the mounting board to the inside top of the window frame. Hang outside-mounted shades by attaching L-brackets to the wall and the bottom of the mounting board.
Attach a cleat to the window frame or wall just to the right of the Roman shade. Raise and lower the shade with the cord, then wrap the end around the cleat to hold the shade in position.
For shades wider than one width of uncut yardage, seam multiple widths together as needed. Match any fabric patterns so the seamed fabric looks like one large piece. If you're making multiple Roman shades for one room from a printed fabric, make sure you centre the pattern the same way for each before cutting the fabric.