Before launching into #pantsweeks2015 (which is what I’m officially declaring next week, btw), I thought I’d go over a recent alteration I did. I know a lot of women have the same problem of pants gapping in the small of their back, and it’s easy enough to fix yourself.

If you can take it apart, you can put it back together. 

The pants I’m working with have a contoured waistband, which is a wider piece with seams. Some pants have a straight cut and narrow waistband (like jeans). Either is fine, but some of the steps may vary depending on the construction.

 Start by pinning out what you need to take in. You can have someone help you if you need, or overlap and pin flat if it’s easier. Fixing this specific problem is done by altering the center back seam of your pants. If your waistband isn’t pieced, that’s okay. We’ll make a seam. Make sure you pin out not just the top, but down the length of the seam as well, so you know how gradually you need to ease back to the original stitching line of the pants.

 Once you have them marked, start ripping. Open up the top and bottom of the waistband. Take out any belt loops paying attention to how they were sewn in. Any under stitching or “stitching in the ditch” should be ripped back inches further, otherwise you won’t have enough access to the seams. You’ll probably also have to take out the garment tags.

 Mark and stitch along your new center back seams, as you pinned out. If you need to create a seam in the waistband, mark the center where it met the seam at the top and bottom and fold, then sew your alteration.

 Rip out all the original stitching in the areas you’ve changed so you can open the seams and press flat. If you had to create a seam in the waistband, you can press to the side or cut it down the fold and press open. If your center back seam was also originally pressed to the side, you can do so and alternate your seam allowances of the waistbands to distribute the bulk.

Try them on now if you’d like to check fit before reassembly.

Tip: For most of the alteration, I use regular poly thread. If your pants have a thread that looks thicker or a different color, make sure to purchase specific topstitching thread and a topstitching needle. If you use a regular needle the thread will split and recoil; it’s really worth the investment of a few dollars. Especially on jeans.

Top row: How the understitching looks, and why it needs to be ripped back further to get to the seam. Bottom: After the seam is sewn, picking it back up and reconnecting it.

Sew the tags back on if you wish. Sew the waistbands back together at the top, reinserting a belt loop if one went here. Connect the understitching or topstitching if there is some here. (Understitching is the line of stitching on the facing that tacks the seam allowance out of the way. It allows for a better fold.)

Top: aligning the stitch lines, placing the belt loop back in the seam. Bottom: letting the seam allowance lie where it wants.

Then sew the bottom of the waistband back to the pants, again reinserting a belt loop if one went here. Tip 1 (not pictured): often times by taking in the backseam, you’ll end up with more of a pointed line than a smooth curve. When setting the facing or waistband back on, set it up a bit higher than the original seam line to smooth the curve back out. Tip 2 (pictured): if you pressed the center back seam allowance to the side, don’t try to force it to match up with the other seam allowances at the top. By altering this seam, you’ve altered the angle, and it will not align. Make sure it’s lying flat, and pin it as such before stitching the waistband.

Top row: stitching in the ditch. Bottom: finished stitching in the ditch, from the outside and inside.

Press all seam allowances the way they want to go. Prep, pin, and sew the facing or inside of the waistband back down either with topstitching or stitching in the ditch, meaning along the seam line where the waistband meets the pants. Finish reattaching any belt loops that required topstitching.

Top row: reattaching the belt loop. Bottom: finished.

Done! Not so bad, right? Alterations are really only backtracking the order of steps, changing what needs to be changed, and putting the garment back together. Try it out and see how you do next time something just needs a small tweak. As long as you don’t cut anything permanent, your local seamstress can always bail you out if you get in over your head.

No more gap!

Happy sewing!