{tutorial} The Seat Seam Adjustment

Happy Weekend, friends! In my Capsule Wardrobe group, this is our "Saturday Sew and Tell" day - but, with stomach bug and strep throat hitting my house simultaneously this week (Mean, universe. Mean.), I'm a little less "sew" and a little more "tell" today. So I figure, let's make it a good one!

My friend Katie has spent the week leading our group with her Back to Basics wardrobe series, and my friends over at Love Notions just released the super cute Caye wide-leg pants; so naturally, fitting pants is the hot topic this week.

Whenever we talk pants, we inevitably talk about "the flexible ruler trick!" - which is touted as magic (and really can be!) but needs a fair amount of explaining to be done accurately. I've been meaning to illustrate this process since the original resource (thanks for sharing your wisdom, Maria Denmark!) somehow went sans-photos. 

So here I am, officially welcoming you to my tiny rental unit for a quick and dirty...

Seat Seam Adjustment Tutorial

Forgive the cell phone photos and smudgy tabletop. I'm lucky to have found the motivation to blog at all - but I won't beat the missing sew-jo dead horse for you twice in one week. 

Here's what you'll need!

  • Tape
  • Wax paper
  • Rubber Band
  • Permanent marker
  • Front and Back pants pattern pieces
  • Flexible Ruler (or tin foil)
  • Your bod. (Or whoever's body you're fitting)

I had the wits about me to sew up some joggers when I felt the first tickle in my throat threatening-impending-illness. If I was going to be couch-bound for days, I at least wanted to be comfortable! So I snatched my Greenstyle Brassies pattern pieces for this tutorial. Go ahead and trace yours on wax paper, too. You'll notice above that I traced multiple "crotch points." My booty-full friends out there will want to do the same. You'll see why in a bit!

First, we'll need to measure our seat-shape. (You can call this your "Crotch" shape - and some fitting books will use that word instead - but it makes me gag, so I'll stick with seat for the most of this tutorial) Grab your flexible ruler or your tin foil.

If you're going the tin foil route, you'll need about a 30 inch long sheet. You'll fold it "hot dog style" a few times and/or twist until it's about an inch thick and flexible. 

Now we get personal. Mold your ruler/tinfoil to your "seat". Use the rubber band (or a piece of masking tape, or a wonder clip, whatever you have handy) to mark the inseam intersection or "crotch point." Also mark your desired front and back rise. I did so here by folding over the excess.

Now return to your pattern pieces! Overlap the seam allowances for the first 1-3 inches and tape in place. (It's ok if/when the pant legs overlap at the bottom.) This creates a "U" shape we'll compare to OUR "U-shape."

Now line up your ruler's "crotch point" with your pattern's "crotch point." (Yes, this is killing me *gag*)

Lay the ruler down and observe: (scroll through each image)

If your rise is too low AND your seat needs more room, size up and start again.

If your rise is correct, but your seat shape isn't generous enough, size up only those inseam points to close that gap (the yellow arrow above). Now we've made more space for our beautiful booties! 

(Side note: This is part of my standard "seat adjustments" these days - and I size up the inseam point on the front pant piece also. You'll grade back down to your size's leg line over the first few inches of the inseam.)

Now that there's enough room for our "seats", let's look at the remaining differences in our seat shape vs the pattern's: (scroll through)

To rid myself of wedgies, I'll trace MY SEAT SHAPE against the pattern's... 

Now I'll cut my fabric along this new, lower curve, and solve all my "saggy booty" wedgie-woes! But I can't express enough how important this simple trick is to helping me find the right size for my "seat." It also predicts rise problems, wedgie problems, and indicates the need for a full belly, full booty, swayback, and other common adjustments. THIS is why we muslin! 

I hope you give it a go this weekend, or at the very least have more confidence to tackle fitting pants. Good luck!