How to Make an H Seam Quilt Backing

I worked on a guild quilt over the weekend.  When I laid out the backing fabric over the top, I realized that it was going to be really close on the length if I only used two widths.  Using a third length would be really excessive though.  I was only short a few inches.  

Sometimes when I am faced with this situation I piece an extra strip for the backing.  For example,  I have used extra blocks, a checkerboard of squares of leftover fabrics from the top, or pieced heart squares for the back.  In the best case scenario, you will have accounted for this and have enough extra backing to make a frame of sorts around the pieced area.  

You may wonder why I'm saying you want a frame.  Well, it's really hard to get a pieced backing perfectly centered on the quilting frame and since it's fabric there is a chance it will stretch slightly or it may shift a bit during the quilting process.  Plus, if the piecing goes to the edge, part of it will get trimmed off because the backing needs to be bigger than the top.

In this case, I did not have any of the top fabrics, but I did have loads of backing fabric.  So I made what I call an H seam.  That way, I get the little extra length I need, but I don't need to use quite so much fabric.  

Here's how you do it.

1.  Cut two pieces of fabric to be six to eight inches wider than the width of your top.  For example, if your top is 60" wide, cut two pieces that are 66" (one yard, 30").
Blue represents quilt top.

2.  Remove selvedges only for the parts that will be in the seams.
3.  Cut one piece of fabric that is half of your measurement plus 3".  This 3" measurement gives a little bit of wiggle room.  Using our sample measurements above, cut a piece that is 36" long (one yard). {66/2 = 33" +3" = 36"}
4.  Cut this short piece in half along the fold.
Cut along center fold, as designated by blue dotted line above.

5.  Sew the short edges together using a 1/2" seam allowance.

6.  Press the seam open.

7.  Trim off the selvedges and square up the piece if necessary.

8.  You should now have three pieces of fabric:  two that are the width of your quilt by 44" and one that is 22" by the width of the quilt. (Note: dimensions may vary since most quilting fabrics no longer measure 44" wide.)

9.  Find the center of the long edge of each of the long panels and mark with a pin.  

10.  Matching centers, sew the long seams using a 1/2" seam allowance.  Press these seams open.

11. Trim the sides to be square as needed.

12.  Your backing should now look like this--pictured with right side down, seams up.

My drawing is not quite to scale, but I think it illustrates the process pretty well.  I feel that the H seam not only saves fabric, but it is a big enough piece that it doesn't alter the integrity of the back.  It would look odd if I inserted a strip that was only a few inches wide.  I don't feel that the seam is very intrusive in the look of the backing in most cases. I added approximately 18" to the backing on this particular quilt.  If you truly only needed a small amount, I'd say you could trim it down to around 9", but I probably wouldn't go smaller.  I really feel that the 18" or so on this looks better.

And here is the quilt after I got done quilting it.  

The backing seams are not very easy to see, right?  
The quilt top pattern is from the book Winter Wonderland by Sherri Falls.  The quilt was made by members of my quilt guild. I used Loophole for the quilting pattern. The backing is Moda Grunge with stars on it.

I hope you find this method helpful.


  1. Fortunately it has only happen to me once on a quilt of my sisters. She thought the backing fabric was large enough.I will keep this in mind. Thank you for linking up to Put your foot down. Very pretty quilt.

    1. Thanks! I should add that I have had too short backings before with no additional fabric available, so I've just basted extra fabric to the top and bottom so that I can attach it to my frame.

  2. Great tutorial on the H back.