Pressing Quilt Seams

Person using an iron to pressing a seam open on a blue-and-white striped fabric.

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There's one quilting technique that's sometimes regarded as a rule: pressing seam allowances to the side, rather than open, to help "strengthen" the quilt. However, many quilters don't think that pressing to the side is always a must.

There are no rules in quilting—other than standard safety concerns such as rotary cutting safety guidelines. Pressing depends on two things—personal opinion and what's best for the current project.

Pressing Seam Allowances to One Side

Most quilters usually prefer to press seams to one side because a little bump called loft forms when two layers of fabric are pressed together along the length of a seam. Lofts of adjoining seams are ideally pressed in opposite directions so they will butt against each together when placed right-sides together for sewing, helping to create perfectly matched seam intersections.

It's nearly always best to use straight pins to hold edges of patches together when sewing because aligned edges tend to shift as units move through the sewing machine, even when the loft is there to help stabilize the match points.

Tips to Help Keep Seams Aligned

  • Stab a straight pin right through the matched seam lines and pull it taught.
  • Use extra pins to align the remaining edges as necessary.
  • Try to remove the pins as the needle approaches to avoid breaking a needle.

It's easy to determine if the pin used to match a seam is in the right spot. The pin should glide through the fabric with little resistance—it doesn't have to travel through lots of layers when seams are aligned. The pin holds the patches in place and you know the alignment will remain.

Pressing Seam Allowances Open

Many quilters always press seams open, with good results.

  • Press open when lots of seams come together in one spot, creating too much bulk.
  • Quilt tops are flatter when seams are pressed open; that problem becomes more of an issue when using heavier fabrics such as flannel or denim.
  • Quilting, especially hand quilting, is easier when seam allowances are not doubled up.
  • Most quilters press seams open when making the backing for a quilt.

All About the Bulk

If you decide to work with seams that are pressed open, definitely stab a pin through intersections to be sure that seams are matched for sewing. Without loft as a guide, it's a little more difficult to know for certain that patches are aligned correctly.

No matter which method you decide to use, remember to press, not iron, to avoid stretching the patchwork. Move the iron carefully and let its heat and weight do most of the work. Take special care not to stretch when using steam to press.