Piecing backing fabric
 

I have made numerous quilts and have had to frequently piece the backs but my current one is just a little short on the width - my quilt is 45.5" wide and the backing is 43". Normally, I need closer to two widths of backing when I am piecing them so I generally just piece up the centre and off I go.

However with the measurements being so close I am not sure if I should add 5" to each side or add 10 " to one side. I think it would be a bit of a nuisance dealing with the little bit of fabric on each side when I am attaching the binding so I am leaning towards the larger measurement. The seam will not be in the centre of the backing if I do it this way - is that an issue?

I would love some advice please!

Either way would work! So, it's 6 of one and half a dozen of the other, LOL. I'd tend to just add the one 10" piece and only have one seam to make, but it's totally up to you.

This is the perfect situation for a diagonal pieced back. I have done this several times and it amazes me every time.

https://www.flynnquilt.com/free-lessons.htm

you could also do two seams with the added fabric placed somewhere off center. You would cut the main backing into two pieces and the additional fabric between the two pieces. The added off center fabric could also just be made of left overs from the quilt front or other coordinating fabrics. I would not try and center it. It is hard to center stuff on the backing.

I second Wesing's advice on the the Flynn method.

I piece backs a lot, sometimes by choice! My main goal is not be on a typical fold line, in your case I would add one skinny band to your wide band -- if you don't do the diagonal. Back in the day the usual technique was if you needed two widths, you cut one piece in half the long way with a skinny-wide-skinny. That was mostly about the fold line. I typically use a 1/2 seam and press open and flat.

Maybe some long armers will respond to this thread. I believe the preferred seams for them are horizontal and not vertical, but I'm not sure on that. I've done it both ways with my projects.

Thank you all for your advice :)
@wesing I had heard about the Flynn Quilt method but had never looked it up - I think this might be the solution I will try for this one. Thanks for the link!

Yes. The preferred seam for the backing is horizontal. If the seams are vertical when you mount them, they tend to distort the quilt sandwich as you roll it onto the takeup roller as the seam allowance on the vertical seam will build up. However, depending on the size of the table and the quilting design, the longarmer may be able to mount the quilt so the length goes horizontal. I sometimes do that as my usual quilting for myself is a free hand meander with extras thrown in. I don't have a computer on my longarm. Mounting the quilt along the length rather than width sometimes makes better use of my batting and also, I don't have to advance the quilt as often this puts the width on the belly and takeup bars. I have a 12 foot table so that is 144 inches minus the bit I need so I can access the bobbin.

Here’s a calculator for diagonal seamed backs. Makes it very easy.

If the quilt is only 45" wide, it probably isn't very long either, so the direction of the seams on the back wouldn't be an issue. It's only when the vertical seam builds up as the quilt is rolled that there's a problem.

SewingPup and Dunster ... agree with what you have said, though I don't think Mackie noted whether the quilt will be long armed or domestic machine quilted or perhaps even tied?

Mackie ... another way some have handled similar situations is to use extra blocks from the front on the back to give some extra width. It would mean splitting the backing fabric to allow you to piece in the extra blocks and not necessarily down the middle. I usually go for about 2/3 and sometimes add extra blocks both horizontally and vertically. Or just work up a simple design of leftover pieces of the front fabrics for the backing.