Putting the parts of a slipcover together seems very straightforward. That is, if you want it loose. Loose is code for messy in my estimation. I like my furniture covers TIGHT. So, if you want your slipcover to fit like upholstery, they must fit well.
Attach the gusset to the cover using the same procedure as with the backrest…
- Pin fit the gusset onto the cover.
- Trace and mark the curve.
- Stitch the seam.
- Slip it on the chair to test the fit.
Just as when handling the curve on the backrest, trace the seat curve on paper to use as a reference when sewing.
With wrong sides out, match the traced seamline on your gusset with the seat edge [not the fabric raw edge] and pin it to your chair to prevent movement. The traced seamline is visible in the picture – that is, if you look very closely. I have not yet pinned in the seam.
Find the corner – or pivoting point – on the cover. I marked the seat edges with a yellow pencil and pinned the front portion down. I removed the stabilizing pins reduce distraction and illustrate how easy it is to make this determination. Leave yours in except for the corner-most ones.
This is a closeup of the match point between the cover and gusset at the front corner of the seat. Although it is not a sharp angle, taking care to keep these matched will lessen pulling after you cover is complete and someone sits on the chair.
Pin the gusset and cover together along the seamline using your pins as if they were the final stitches. This side seam only runs from the bottom front along the curved corner to end where the side of the chair stops. Do not continue sewing around the back. Note the yellow pin head visible at the end of the side seam indicated by the yellow arrow.
Stitch this seam carefully easing in fullness of the cover at the curve. At left, are the pinned together pieces lying flat on my table. Below, I have pulled my fullness behind the presser foot, allowing me to stitch flat for a little while. The longer side is down, facing the feed dogs.
After stitching, trim excess seam allowances down to a manageable level. I serged mine, but I live dangerously. If you don’t mind doing the task more than once, reduce to about 3/4″ for your first fitting.
Turn your nearly complete cover right side out, and try it on your almost refurbished chair. Check for fit. Pay special attention to the curves. Make sure the seat pleat is firmly tucked in. If it is not, the curves at seat front will appear too large for the chair. If your seams pucker or have pleats, simply remove the stitching around the blemish, re-ease and re-stitch.
I veered off course on one side of my seat, and needed to redo that curve. It was easy. I just repeated the pin and sew step in that place.
Clip and grade seam allowances to diminish show through, if you have not already.