How to Piece a Quilt Top
Once the blocks are cut, the top comes together row by row. A consistent quarter inch seam and nested seam allowances are what keep the corners meeting and the finished top flat.
Materials
- Cut fabric squares and blocks
- Neutral cotton thread
- Fine pins or clips
- Spray starch
Tools
- Sewing machine with a 1/4 inch presser foot
- Iron and pressing board
- Rotary cutter and acrylic ruler
- Design wall or large flat surface
Steps
- 01
Lay Out the Blocks
Arrange every block on a design wall or a large flat surface before sewing anything. Step back to judge the color and value balance, then photograph the layout with your phone. Keep the photo on hand so you can return each block to the right spot as you sew.
- 02
Chain Piece the Rows
Sew the blocks of each row together with right sides facing and raw edges aligned, using a true 1/4 inch seam allowance. Feed the next pair in without lifting the presser foot or cutting the thread. Snip the whole chain apart only after the row is complete.
- 03
Press Each Row
Set the seam first by pressing the closed unit with a hot dry iron, then press the seam allowance to one side. Alternate the direction from row to row so that neighboring rows oppose each other. Pressing rather than ironing keeps the row from stretching on the bias.
- 04
Join the Rows
Place two rows right sides together and push the opposing seam allowances apart until they nest at every intersection. Pin each junction so the seams cannot slip, then sew with a 1/4 inch seam. Slow down or hand turn the wheel where several seams stack up.
- 05
Press and Measure the Top
Press the finished top from the back to flatten the long seams, then give it a light press on the front. Measure the width at the top, middle, and bottom edges. A difference of more than half an inch usually means one seam allowance wandered off.
- 06
Add Borders if You Want Them
Measure the top through the center rather than along the edges, and cut the top and bottom borders to that measurement. Pin the border at the center and both ends, easing in any fullness as you sew. Repeat the center measurement for the side borders so they stay straight.
The true quarter inch
Quilt patterns assume a quarter inch seam allowance measured from the needle to the cut edge of the fabric, and a fraction of a millimetre of error compounds across a row. Test with two scrap strips: sew, press and measure the unit against the width it should be.
If the test piece comes out small, move the needle position instead of trimming later. A quarter-inch presser foot or a marked guide on the throat plate gives you something to watch while sewing, which is far more reliable than judging by eye.
Chain piecing and keeping the layout
Chain piecing feeds pairs through the machine without cutting the thread, so you stay in rhythm and the seam allowance stays consistent. Snip the chain apart only once the row is complete.
Keep the layout photo beside the machine as you work, so each unit goes back where it belongs. Losing track of the arrangement is the main reason a carefully planned quilt ends up rearranged.
Pressing for flat, nested seams
Set the seam by pressing the closed unit flat with a hot dry iron, then press the allowance to one side. Pressing rather than ironing, lifting and placing instead of sliding, keeps units from stretching along the bias.
Alternate the direction row by row so neighbouring rows oppose each other. That opposition is what lets the seams nest later, and nesting is what makes intersections meet precisely.
Joining rows without shifting
Push the opposing allowances apart until they lock at each intersection, then pin on both sides of the junction so it cannot slip. Sew with the bulk of the seams facing up where you can, because the feed dogs then help move it through evenly.
Where several seams stack, slow the machine or turn the handwheel by hand. Forcing through a thick junction bends needles and shifts the seam line by a millimetre or two, which is enough to misalign a corner.
Squaring the top and adding borders
Press the finished top from the back to flatten the long seams, then measure the width at the top, middle and bottom. A variation of more than about 1 cm over the height usually means one seam allowance wandered.
Measure the top through its centre when cutting borders, not along its edges. Pin the border at the centre and both ends first and ease in any fullness between, so the border does not pull the quilt out of square.
Frequently asked questions
- Why do my quilt corners not line up?
- Nearly always a seam allowance that is slightly off, because errors accumulate across several seams. Test your quarter inch on scrap strips first, and make sure the seams nest rather than push against each other.
- Should quilt seams be pressed open or to one side?
- Pressing to one side is traditional and is what allows seams to nest at intersections, which improves accuracy. Open pressing can be flatter on very bulky seams, but it removes that nesting.
- How do I keep the finished top flat?
- Press rather than iron, alternate the seam direction row by row, and avoid stretching bias edges as they go through the machine. Squaring up the finished top also removes any wavy edges.
- Do I have to add borders?
- No. Borders add size and can help a busy design settle visually, but a pieced top can be layered and quilted as it is. If you do add them, measure through the centre of the top rather than along its edges.