Closet Core Pietra trousers (pattern hack)

Closet Core Pietra trousers (pattern hack)

The Pietra Pants pattern grabbed my interest as soon as it was released. The slim legged version shown on the pattern cover immediately made me think of a certain pair of high-waisted trousers from Zara that was all the rage a year or two ago. I loved the slim lines, central seam, and those deep angled pockets on the side front. But what I didn’t love is the elasticated back waistline, which has never ever worked well for me and my rear. So I set out to hack the pattern and eliminate the elastic!

The pattern

The Pietra Pants & Shorts pattern by Closet Core Patterns is available in sizes 0-20 (PDF and Print, 33″-44″ hip) or 14-32 (PDF only, 45″- 63″ hip).

I made view A, the wide-legged trouser.

The fabric

The fabric is a lightweight herringbone wool suiting from my stash. Unfortunately I can’t remember where I got it from!

Sizing and alterations

I cut a straight size 10, as recommended for my waist and hip measurements. (They don’t usually fall within the same size, so I might have to investigate some other Closet Core patterns as it seems their block might be a good match for me!).

I made two alterations.

The first was to remove the elastic. I explain how I did this in the video linked below, but in short what I did is:

  • I extended the height of the back trouser pattern piece to the height it would have been with the waistband sewn on (adding an extra seam allowance along the top edge).
  • I measured the waistline of the pattern (on the pocket, centre front, and my adjusted back pattern pieces, excluding seam allowance). I subtracted from this my ‘high waist’ body measurement (i.e. my circumference a couple of inches above my natural waist).
  • I divided the difference by two and then split it across two darts on the back trouser piece and a reduction at the side seam.
  • Lastly, I drafted a new back facing.
  • (EDIT:) when sewing, I inserted a concealed zip at the centre back.

The second change I made, and it’s a small one, was to split the pocket pattern so that I could swap out the bulk of the pocket piece for lining rather than the wool. This was just to reduce bulk and avoid having the pocket fold show through when ironing the trousers, as the lining is more lightweight.

As this is high waisted, you ideally want to end up with zero ease at the waist, and I did find that because my stomach varies throughout the day, at times the trousers ended up still feeling slightly loose so I want to tighten up the trousers at the waist by taking the seams in a bit on the trouser and the facing. On a future version I might also incorporate some extra stabilisation around the waist seam to combat the tendency to grow. I’m also tempted, on a future slim-legged version, to incorporate a button fly at the centre front of the trouser.


Closet Core is known for clear, detailed instructions and these ones don’t disappoint. I only read the instructions through once, to figure out what the original construction was so that I could see how to hack it, but they made perfect sense. For my hack, I simply made the outer shell of the trousers and then sewed the facing pieces (centre front, side front and back) together before attaching the facing to the trousers in the usual fashion.

In case you are wondering, for the centre front seam you are instructed to finish the seam allowances together, press to one side and topstitch.

The verdict

I think the design of the Pietra trousers is fantastic. It has lovely details and even the original elasticated back waist makes sense for the fabric types Closet Core recommends for this pattern. (They specifically advise you not to use heavyweight wovens because they might create too much volume at the elastic waist). Combined with the great instructions I think this is a really nice little pattern.

Until next time… happy sewing!

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