Even if you regularly sew lovely dresses, it can be easy to forget that you must also often sew the correct foundation garments for those dresses. A child’s poofy skirt, for instance, for all its flounces and ruffles, simply will not poof properly unless she is also wearing a full petticoat underneath it.
Fortunately, just as you can refashion formal dresses into a new garment, you can also often find the material for the perfect petticoat hiding under one of those same Prom dresses that you’re already planning to rip up and re-sew. And unless you actually want to search for real crinoline fabric (which is a type of stiffened cotton that’s hard to find these days), it’s better to find the nylon-based tulle that’s usually used for underskirts and upcycle it, rather than purchasing it new.
Formal dresses with puffy skirts will almost always have a tulle underskirt that can be remade into a petticoat. The underskirt will usually be sewn to a silk-weight lining that will be sewn to the dress at some point higher up. To remake this into a petticoat for your own use, you will be looking for a dress that has a tulle underskirt the approximate length that you desire (you can go even a couple of inches shorter than your desired measurement without the difference being noticeable), but whose dress has a waist that is much larger than what you require, because you’ll get some extra puff in your petticoat by gathering it to fit your waist.
For my daughter’s rainbow dress, also made from upcycled Prom dresses, I used the underskirt from an adult’s knee-length formal dress–that waist-to-knee length in the adult’s dress was the perfect waist-to-ankle length on Sydney, and gathering the waist size to fit her gave the petticoat a huge amount of puff.
Cut the underskirt away from the formal dress, then cut it again 2″ above the tulle, so that you have a completely intact petticoat, with two inches of the lining fabric above it. Crease the top edge of the lining fabric under to hide the raw edge, fold the lining in half, and sew it down to make an elastic casing, leaving a couple of inches unsewn to insert the elastic.