Pleats (quilting) and tuck & roll have been used in automotive interiors since the beginning of enclosed interiors. Not only do they add to the looks, but also keep the material (fabric, vinyl, leather) from becoming full of stretch wrinkles.
Pleats, or actually quilting, is the sewing of the upholstery material to a layer of padding with a backing fabric. The quilting is usually done in a combination of lines to form a design. Lines, diamonds, squares, rectangles, etc. Even free form quilting (although you have to consider the shrinkage) can work. Basically any design you can dream up can work with a little planning. When complete, the stitching thread shows on the top side of the upholstery material.
Most quilting pleats are done in ½ or 3/4 inch foam backed with muslin or denim. The density of the foam will determine how well the pleats stand out. The common ½ inch foam with muslin adhered to the back side found in many stores including MACs is good enough for trim panels. If upholstering seats, go to a better grade of foam and possibly move to 3/4 inch. This will hold the pleats better on seats. The cheaper stuff will flatten out in a short period of time.
The common size of straight vertical pleats is 1 ½ inches to 2 inches apart. The big thing to consider and allow for is the shrinkage that takes place for each sewn pleat. Allow half the thickness of the foam for each pleat sewn. So for ½ inch foam allow 1/4 inch extra for each pleat that is sewn. For 3/4 inch allow about 3/8 for each sew. Draw out the pleats and sew using as long a stitch as the sewing machine will sew, through the top material, foam, and backing. Too close of stitching will weaken the material, especially vinyl, and it will eventually tear on the pleat.
True tuck and roll involved sewing a top material to a backing fabric like denim. The top material was either cut in strips or folded over face to face and sewn to a backing fabric. After all tucks were sewn, each was stuffed with horse hair or later cotton (straw if you weren’t watching in Tijuana) using piping tins. Two smooth, concave shaped, long tins were filled with the padding. They were slid down into each sewn sheath and then the tins were pulled, one at a time, leaving the padding in and a rolled appearance.
Today, tuck and roll is done by using the former technique for sewing quilted pleats. Once all the pleats are sewn, lay the material over face to face on the pleat. Now sew through all the layers about a 1/4 inch in from the edge. It’s a good idea to lock in or tie the ends of each so it does not start to come out from the pressure of the padding.
Again, the big consideration to remember is the shrinkage from all the sewing. It will now be about 3/4 inch for each tuck. Pretty common sizes of vertical tuck and roll is ending up about 2 inches to 3 inches wide. So if you start your figuring of 2 ½ “ wide quilting, your tuck and roll will end up about 1 3/4" to 1 7/8" when complete. Any smaller will become difficult to work with. Another common size for wider seats and full benches would be starting with 3 ½” quilting. The tuck and roll will end up about 2 3/4 when complete.
I use a denser ½ inch foam and back it with newer headliner fabric. The headliner fabric has a 1/4 inch of foam bonded to it so the whole thing is now 3/4" and the backing fabric is included. For both quilting and “tuck & roll” only glue the foams and backing materials together. Don’t glue the top fabric, vinyl, or leather to the foam. This allows it to shrink and move with wear and tear.