PBA- Protruding B utt Alteration, PP113


ETA: It’s not de ja vue. You could have read this post before! This post went public before I intended.  It really needed this last edit and maybe one more. 

I’ve noticed that the fitting books all read “if you have this problem, do this” or something to that effect.  So when I tell people I have lived 6+ decades and have a mass of fabric beneath my tush, they look a the “this problem” and  promptly advise  a “do this”  of flat-butt alteration.  However, I don’t think I have a flat butt.

That’ s my b utt. I earned that b utt.  It’s a left over from my childhood when running was my favorite activity; high school when I played the Field Hockey Right Wing; and years of walking as a method of solitude, meditation and exercise.  Now that I’m retired, 2 flights of stairs taken many times daily, keep my b utt high.  When i saw the picture above, I decided I needed a FBA (full-bust alteration) for my b utt. I started looking through my library;  searched the internet but found nothing. (Warning do not search the internet for b utt alterations. You will not believe the finds.)  The general attitude seems to be buy a pattern big enough to go around and your pants will fit.  P&P even suggest that I might want the extra fullness over my back-thighs to fill in and disguise how much I stick out back there.

I gave up and went about my sewing. Until the day I was looking in my books for something else… when I delved into Lynda MacIntyre’s “Easy Guide to Sewing Pants“. This book is not just about sewing pants. It includes lots of fitting information including the elusive PBA Prominent Butt Alteration”.  Although I had planned a quick and easy pair of pants, I had to try this alteration.

I traced both front and full-back pattern pieces of PP113, size medium.  It’s possible I didn’t need to trace the front at all. But I’m unsure of exactly what alterations I’d made. I decided to start from scratch and document the changes like I’d  have alzheimer’s today. I’ll spare you the details of the changes I made (which are normal for me) and jump right to the PBA.   The PBA consists of two slashes one horizontal along the HBL starting at the back crotch going to to but not through the side seam. The 2nd  vertically bisects the first along the grain line. It would look like a big cross. The vertical does not cut through either the waist or hems.  Then the PBA is spread apart, taped into place  and the back crotch line trued.

The first question I asked was how much do I spread the PBA. I’m always trying to add 1 inch ease. On the MSS and Eureka pants patterns, I folded out 1″ of ease from the front, then split the back along the grain line and spread the back 1″ (effectively adding 2″ ease to the back hip.)  Other patterns, I’ve tried to create wedges and curves to add 1″ or more at the side seam.  Believe it or not, the PBA slashing and spreading is a better way of adding ease. I spread the vertical grain line apart  1″.I didn’t want to create a bubble at the crotch seam, so I pulled the slash towards the side seam to open it.  I slipped some tissue paper beneath and tacked the spread in place. I worked from the vertical slash towards the side seam and then again from vertical slash towards the crotch allowing the tissue to fall into place. Surprising to me, the slash along  HBL  also opened 1″ at the back crotch.  It wanted to. It just sort of spread open as I was working towards the side seam and settled into place. Frankly I wasn’t sure of what I was doing and decided to trust the paper.

Once all was secured with tape, I cut fabric.  My fabric was purchased about 3 years ago in Rapid City SD. I think I was at Hancocks. I make it a habit to look for good pant fabrics anytime I’m in a real fabric store.   This particular time Hancocks had splurged and added a few colorful denims.  I purchased two, well I purchased 4 fabrics that day, but 2 were in unusual colors, a light rose-pink jacquard and a periwinkle denim. Both with 2% Lycra. I used the rose pick jacquard today.  It tested with 15% stretch which I reluctantly didn’t take advantage. I mean, I didn’t want to stretch this pair of pants to fit.  I wanted to alter the pattern to fit.  I put the darts and zipper in permanently. Skipped the pockets; serge finished all the edges and then using water soluble thread, stitched the pants together for the first try on.

Heavenly, just heavenly. The front crotch was too long –the same complaint I made about the pants Pam fitted on the DVD. Interestingly the first pair of PP113’s I used the 1″ SA on the back to cover my rear. With the PBA, both front and back side seams are an even 1″ — I’m not using the side seam insurance to fit my backside.  I feel like  the PBA creates  less distortion of the design line.   I’m excited that there is less excess ease over the back thigh and the hem circumference has not increased by my attempt to add more b utt ease.

I ripped out the waistband and reset it  3/4″ lower in front; 5/8 lower on the side narrowing to 0 (or no change) at the center back seam line. Perfect. I transferred the change to the pattern by overlappinig and taping the sides along the side stitching line; slashing across front and sides to the center back stitching line and over lapping the pattern pieces; and finally taping the alteration in place.

I finished the pants by narrowing the lower leg between bottom of knee and hem; 1/2″ each side total 2″ per leg. I also scooped the back crotch just slightly because the first pics showed the back crotch creeping between my cheeks. I’ve not transferred the last 2 changes to the pattern.


The front looks a little large to me. I’d like that ease for trousers, but slacks are a different animal.

This is very close to how I want my slacks to look. I want slacks that hint at shape and fall smoothly from my waist.

I am pretty happy with this pair of pants  I do think they are just slightly large for slacks. They’ve been worn for 3 fittings and about 30 minutes before taking pictures. I plan to take in the side seams another 1/4″ and call this version done.

BUT I’m not 100% satisfied with the PBA.  I wasn’t sure where to place the PBA and chose the HBL.  The fullest part of my butt is about 1″ below the bottom of the darts which is 2″ higher than the HBL marked on PP113. When I think back it makes more sense to place the cross over the largest point instead of 2″ below. The split would then  come back together about 2″ above my knee and not be as wide over my thighs. I’m always complaining about the excess fabric in that area — (it is that symptom that causes people to say make a flat-butt alteration)– when in truth when I’m trying to add ease across my b utt, the area over my thighs is also getting more ease.  I also think that a full one- inch spread could be too much. I see that in the length of the back crotch as well as the over all ease in the back.

Oh yes, there will be another version…..


5 thoughts on “The PBA”

    1. I confess, I haven’t read the Easy Guide to Sewing Pants in a long time either. Like most of the world, I’ve been working with PFRP. Unlike most of the world, I’m not getting great results using Palmer & Pletsch methods. I’m really pleased with the PBA and plan to work with a couple of other alterations in EGSP. It will be interesting to see what you do with the information in EGSP.

  1. Great post! And I love the part about earning your b utt too. That all makes really good sense and is really helpful. I find that most alterations assume you have thighs to match the b utt and thus end up making thights appear bigger than they are – every woman’s dream. (I do have big thigh, but not as big as the other parts). I’ve finally added your new site to my blog roll – brilliant of you to keep posting on the old one as a reminder to us all!

    1. most alterations assume you have thighs to match the b utt

      I think you’re onto something. I really wish there was someway we could find out what their “model” really is. Just knowing that I’m shorter than their model helped me understand that I would always need to make a back waist length adjustment. My frustration was lessened just by understanding that reality. Glad you enjoyed my post.

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