Prepping Fabric

Do you wash all the fabric you buy before working with it?

Fabric manufacture includes processes resulting in a finished fabric, which should not shrink appreciably if correctly laundered. A raw state fabric from a natural fibre, like the knitted silk noil I bought recently to make tops, hasn’t undergone the dyeing and finishing process and will almost certainly shrink . Some natural fibre fabrics shrink over several or many washes, (typically cottons). I pre-washed the noil and I’m prewashing black denim bought for jeans from Fabricland. It has shrunk a little, but not appreciably over the 3 metre length. I’m making up this pattern first.

Cig Pants

Cig Pants

It makes a garment which is smoother under close fitting tops than typical jeans because the zip goes in the side, the shaped waist lies flat and there are no pockets. If it were tighter and made in a jersey it would be leggins.  The denim I’ve purchased has some 2 way stretch in it, good for this pattern. I’ll keep you posted about how it makes up.



Obviously, RTW manufacturers don’t launder thousands of yards of fabric.  They often wash test the sample garment to see if the fabric is suitable before ordering for the full run.

Most fabrics from man-made fibres don’t shrink.  Shrink testing by taking a measured square of a decent size (at least 6 inches) and laundering this instead of the whole length is a good alternative.

Another argument for washing yardage is that it might not be clean enough to work with.  Certainly,  some stuff I’ve purchased from a market stall has spent time in a warehouse, been chucked in a van and stacked on the pavement without any protective cover.

Have you ever bought wonky fabric?

This is much harder, sometimes impossible, to correct. When fabric in the finishing stages of manufacture has been stretched so that the warp and weft are no longer at right angles to each other, or the knit runs across at an angle, it’s a bad bet. Wovens which have a slight distortion can be brought back with the aid of a helper ( three helpers for wide fabric). Each person grabs the piece near the selvedge and tugs opposing the direction of the distortion until the fabric straightens up, finishing with a good pressing . Knits – no chance.

Clothes made from distorted weaves invariably distort in wear. Who hasn’t ended up with a twisted jeans or wonky T-shirt purchase? Inferior fabric or bad pattern lay is responsible.

The most critical part of the cutting out process is making sure the pattern grainline is running parallel to the warp. If you run short of fabric and want to risk a compromise, don’t mess with the grainline on the major pieces.



About jay

I design and draft patterns
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10 Responses to Prepping Fabric

  1. sew2pro says:

    I couldn’t bare to not wash as I’m always thinking “er, you don’t know where it’s been”. With the exception of denim when I’m not so squeamish. I’ve noticed denim (the tough variety, not the stretch stuff) gets unattractive fold marks from the spin cycle and they’re hard to press out.


    • jay says:

      So true… I’m still pressing one spin mark at the very edge of my denim piece – it’s been steamed to within an inch of its life, but still holds on.


  2. mrsmole says:

    I bought some loosely woven fabric years ago in 3 colors to maybe make Chanel type jackets. The good thing was that I soaked them in the sink to pre-shrink and when I went back to pick them up to wring them out, all the threads came away in a huge lump…they must have been glued into place and not woven and the glue disappeared. I kept one original piece to remind myself to always pre-shrink. If I had spent time sewing the garments and then hand washed them I would have ended up with a huge pile of threads and not a jacket…ha ha!


  3. I think you could probably get away without prewashing most fabrics, but I’ve had a few that bled or shrank a lot, so I wash everything first. Another reason to prewash is the chemicals used to treat fabrics . . . I have really sensitive skin, and I wouldn’t be surprised to get a rash from unwashed fabric. I once wore a pair of new RTW socks without washing them first and got a pretty decent rash on my feet.


  4. I pre wash most fabrics now. Getting any shrinkage done and removing fabric dressing helps get a garment that will stay how I expect it to after laundering.


  5. I wash if it looks even slightly dirty or dusty. I also wash natural fabrics, silk or cotton, something that might change. I guess it depends on what I have to work with.


  6. I always pre-wash fabrics because I know that my “dry-clean only” clothes are not going to be worn very often — because of the cost and inconvenience of dry-cleaning. I once visited the basement of a major opera house; there was a full-time employee there who did nothing but “prep” fabrics by the roll. (She was an expert on steaming and pressing, as well as other ways of pre-shrinking, and could cope with any luxury fabric they purchased.) Why waste labor on a garment that will come out of the wash with puckered seams, or get smaller every time you wash it?


  7. fabrickated says:

    Generally no, unless I think it may shrink. On grain – I was ironing an M&S grey pima cotton T shirt last night that has twisted from the day I first washed it. And I was thinking, as I did, that some people will design to get that effect (eg Pattern Magic).


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