Making a quick set of curtains and a valance is something that you can do even if you don’t have much sewing experience. It’s just a matter of thinking through process and calculating for fabric needed and knowing how to use a sewing machine.
Tools needed: calculator, pencil and paper, tape measure, yard stick, pins, scissors, iron, thread and sewing machine.
Decide what color or pattern will work best with your room décor now. Going to fabric store is always one of my most fun times, I keep my imagination open and get swatches of fabrics (and prices) first time to see what all my options are. Take swatches home and start eliminating them by laying them next to major parts of already decorated room (couch, chair, tables, walls, etc). Once you’ve decided on your fabric start measuring.
To measure for material, decide how long you would like valance to be. Where will you place curtains in window? Will you do them café style or halfway down window? Maybe you only want a small space between valance and curtain, use your imagination, draw a sketch of window and do some placements on it to see what looks good.
Once you make these decisions, measure from your top reference point (top of window, top of rod) down to where you want valance to end. Add additional 7” for top and bottom hems(this will give you 3” for top hem, which rod will go through and 4” for bottom hem). Let’s say you want your valance to be 10” long, add 7” for hem and you have 17”. Now measure for your bottom curtains. The same goes here, measure from top reference point (where your curtains will start) to just BELOW or ABOVE windowsill. Add 7” to this length. EXAMPLE: 32” bottom curtain length, add 7” = 39”. Write all this down. For width across, measure across window from outside to outside molding. Depending on how “full” you want curtains will be deciding factor on how much material you purchase. Normal fullness recommendation would be twice window width, or at least ½ again as much. We are going to be very basic, let’s say a normal window is 36” across X 60” length. This means you will need to calculate double width for valance and curtains, but remember curtains are split in middle. Most material will run 36”–44” (regular material) to 60” (drapery & upholstery material) in width. If you choose a fabric width of 36”- 44”, it will be easier to just use width and cut a little off ends it needed.
Now it’s time to go get your material! Take your swatch, sketch and measurements with you! I would recommend a pliable fabric that is easy to work with (cotton, broadcloth, etc). Have your material store sales person help you with calculating amount, and give you any details in laying especially if it has a design going a specific way or has a nap. In most cases, 3-3½ yards should be plenty per window.
Pre-wash material if you choose. If you do not pre-wash material and wash curtains later expecting them to be same length, you may be surprised! If you have pre-washed your material, take it out of dryer, fold in half, wrong side out (if you can tell), like it was previously from store off bolt, and lay it on your surface and smooth it out (table, floor, etc). Do same for 60” width material; this will make it easier to handle. You may want to touch up with an iron.