Quote Originally Posted by Aldisimo View Post
This is how I'd make this alteration on slacks or a skirt. I can't see why it wouldn't work with a kilt.

The idea is to remove the extra fabric from the top, rather than from the hem, so that the garment hangs correctly; you can't just shorten the hem in the back, whether it's a plaid or not. (I'm assuming this is one of the kilts that you've made for yourself.)

1. While you're wearing the kilt, have someone check to see how much sagging there is. I hope it's not more than about 1/2" so you don't disturb the drape of the garment.
2. Remove the waistband behind the aprons (the back waistband, over the pleated area).
3. Chalk a smooth curve from one side (where the waistband is attached) around to the center back and down as far as the sagging, and then up to the other side (where the waistband is attached). You're drawing a new seam line that eliminates the extra sag at the top of the pleated area. Be sure not to draw a line that goes to a point at the center back and then up again to the waistband. It's got to be a smooth curve that continues the seamline from the front, around the back, to the front again.
4. Baste the waistband on so that you can check the alteration.
5. Adjust if necessary. When it's perfect, trim off the excess at the top of the pleats and then re-attach the waistband, being sure to smooth out the whole seam. You might need to extend the re-sewing a little into the apron area.
6. Now that you've raised the back side, you've also raised the fell by the same amount. You have to measure down the amount of your fell from the new back waistline, and stitch the pleats down to that level. At center back the new fell should be exactly the amount that you cut out, and the new fell line should mirror that smooth curve you drew.

Keep a note about it so that you can make the adjustment on future projects before attaching the waistband.

P.S. I have the opposite problem. Because I've got a bubble-butt, whenever I've made slacks for myself I've had to add extra at the center back. If I don't, there's not enough fabric to go around the curve, so the waistband and belt get pulled down in the back. I'll probably need to do this with the kilts I'm making so they don't hike up at the bottom.
This may work for slacks and skirts, but it will not work for a traditional knife pleated kilt. You must first start with understanding what is the root cause of the problem. Is the waist band equal to or bigger than the waist. Is the buckle in the proper position for the size of the waist. Was the kilt made by traditional method or is it a economy (shudder) kilt. Is the waist the same as the hips? Is the kilt tailored to the person or is it an off the shelf kilt?

We need more information before we can modify the kilt. Do not cut until you know the root cause of the problem.