Wanting to match a chaise to our existing sofa, we purchased the SÖDERHAMN chaise, but not the upholstery covers.
There would be three parts to this hack:
a) replace the chrome legs with walnut legs,
b) use custom upholstery, and
c) modify the backrest so it would better match our sofa.
We purchased the walnut legs from an online retailer and applied three coats of tung oil ourselves.
We ordered upholstery covers from an online retailer choosing Silver Grey Brinken Herringbone fabric.
Finally, we modified the backrest:
1) We stripped off the dust cover and all of the foam.
2) We kept the plywood structure but built a box out of it using MDO. Although not shown in the photos, the backside of the box was closed using a piece of cardboard stapled to the framework to keep the overall weight down. Note in the photos that we added a taper to the box so it mimicked our sofa arm.
3) We brought the box with 2 yards of fabric (ordered from the same online retailer mentioned previously) to our favorite upholsterer. He upholstered the box using our fabric, 1-inch foam only on the backrest side, batting covering the four vertical sides, and fox edging where needed.
4) We carved a plank of walnut with the same bevels on the edges. This plank was then coated with three coats of tung oil. An M-4 threaded insert was put into the center of the underside of the carved plank. An M-4 machine screw was inserted into this. We inset a keyhole hanger plate into the top of the box (see photo). With the M-4 machine screw perfectly adjusted, we slid the walnut plank over the top of the box until it caught the keyhole hanger plate and “locked” into place.