So, before I start, let me mention that my primary office chair is a used Steelcase Criterion office chair that I picked up used for a song about a decade ago. The thing was made in the mid-90's and was still in great shape at the time, but after another decade of regular use, the foam padding finally died on me and the thing got deeply uncomfortable to sit in. This isn't really a brag and look at what I did post, but a long post describing how I did it so others might be able to reproduce it themselves.
Given how overengineered and well built the thing is, and the reputation of the chair being a BIFL (buy it for life) item within a few communities, and how little I spent on it to begin with, I didn't want to just pitch it... but rehabilitate the thing. So, this post is a bit of information on exactly how rugged and durable the Steelcase Criterion is, how much it's worthy of the BIFL title, and how surprisingly easy it is to fix it up if you know how to tear it apart, creatively wield an electric carving knife and operate a sewing machine.
Now, there's an issue normally with trying to redo the foam on one of these chairs - getting the replacement foam to fit and match the curve of the plastics, and I figured out a reasonable solution even if I did bungle it on my own attempt - but! Learn from my mistakes, and apply the info yourselves.
At first, I reached out to
Crandall Office Furniture to ask if they had any replacement foam pads for the chair available. During our dialogues, David, who went above and beyond in his dealings with me, got me a price for replacement foam and informed me that they'd never figured out how to replace the raw foam and get it to look right, so they had to basically bust up an existing chair and send me out a replacement seat and back, along with the hard backing foundation the foam was attached to. I felt bad about breaking up an already fixed used chair, and the price reflected that, so I researched and talked with some local upholstery guys... and then I found this video, and the wheels started to churn and there was spitballing with the upholstery guys who they themselves originally just suggested leaving it square and cut bigger, though it didn't look right at all when done, or cut it two inches larger and use heat to pinch the edge to a point:
https://www.youtube.com/watch?v=13W4Awb7SYUThis video will be useful to understand how to attach the new foam pad later on and the nifty trick I worked out to fake the custom bullnose form.
After talking a bit with David some more, and
him so kindly providing a custom video for a teardown on the chair to remove the seat and back, I went off to the upholstery shop for materials.
I bought:
24"x24"x2" 50lb. density upholstery foam slab (x2)
1 yard of heavy polyester tweed fabric
1 yard of foam headliner cloth
1 can Camie 313 fast tack upholstery adhesive
TOTAL - $55-ish with tax.Now, I actually made a mistake in my actual purchase, but I've revised so others don't repeat my mistakes. I actually bought 1.5" slab for the seat plus a 0.5" heavy density foam slab to make the seat firmer. The end result is a bit too firm, honestly, but it should wear like iron all the same, it also jacked the price up another $5 for that mistake. Don't overdo it yourself, though. Just roll with the single slab of 2" foam.
I also made two mistakes in my own fabrication, but my instructions will reflect the changes I'd do if I were to do it all over again. 1) I used the old fabric coverings as a template for the new fabric - big mistake; 2) because of #1, I destroyed the perfect roundover I had with the foam and had to staple the fabric tightly into place instead of using the drawstring method to give a nice smooth and professional finish. Meanwhile, the end result is good enough to live with, so it is what it is. I might make some piping bias tape with the leftover fabric to fill in the gaps sometime later, but for now I'll live with the lumpy gaps. Learn from my mistakes, people.
Anyway, here's the best way I found to get the perfect sized roundover for the foam:
-Trace the seat and back foundation to the center of each 24"x24" slab, leaving at least two inches around each edge
-Cut the foam along that line at a 45° angle, leaving a 2" flair bigger than the foundation side of the foam for the outward facing surface, but there's a trick to this
We'll get to construction methods here in a bit, but it's really easy, excuse a little bit of sewing.
Now, taking off the old foam was a long and messy job for me, and after I finished, David told me it's easier to use hot steam on the old foam to loosen up the glue. So if you have a way to, use hot steam to take off the old foam. Otherwise, you're going to fight some amazing glue with a heat gun and a scraper for a while making an awful mess in the process.
To cut the foam at a 45° angle, I took an old door and ran the blade of an electric carving knife up through the old doorknob hole, mounting it at the 45° angle underneath and used a zip tie to keep the trigger on. It took longer to set up and take down the carving knife than it took to actually cut the foam, and it did a clean and excellent job of cutting.
This is where you should learn from my mistake. Instead of tracing the old fabric, use the oversized edge of the foam slab after cutting to make the new fabric template, and cut the fabric with an extra 1/2" of material at the edge all the way around (extra 1/2" radius, or 1" diameter) and be sure to mark the top and bottom for alignment. Same with the headliner foam cloth. From there, take the old bias tape and string from the old fabric covering off and sew it around the edge on the back of the new fabric. If you set the foam back on top of the fabric, the foam should go up to the inner edge of the bias tape.
From here, take the large slab of foam on the larger diameter, outward facing side and spray glue its surface and the foamy side of the headliner cloth and press together nice and smooth. Spray the front surface of the headliner cloth after attaching it to the foam block and the back surface of the fabric and then stick those together, making sure you keep everything nice and smooth and leave it be for a while to cure. You should now have a foam slab with upholstery fabric on one side with a drawstring around the inside edge, just outside the larger outer foam slab edge.
Then, you spray the smaller diameter back of your upholstered foam slab, trying to stay away from getting any glue on the angle-cut edge, and the foundation. Then, you press the two together, lining the edge of the foundation up with that inner beveled edge of the foam, and pressing the center of the foam in to try and ensure the entire foam slab takes on the curve of the foundation it's glued to.
After letting that cure for a few minutes, you then take the spray adhesive and spray the remaining visible beveled edge of the foam and a bit of the outer edge of the foundation, trying not to get it on the last remaining bit of fabric at the edge (it targets pretty easily). Let the glue sit for a minute to get sufficiently tacky, and from here, you just start rolling over the foam on itself to create a rounded bullnose edge. Once you've gotten enough folded over, pull the string as tight as you can and staple it into place. The pull should help smooth out the edge and the fabric puckering on all the curves and pull the fabric up over past the edge of the foundation. Pop in a couple extra staples in the spots where you pulled staples out earlier to free the old fabric, and let it cure again.
Reassemble the chair and you're done.
Now...
Why the headliner foam layer? It's a thin foam layer with more stretch and give than the primary layer, and allows you to glue the fabric to the foam in such a way as to help keep things smooth as you pull the string together to tighten the cover.
Why glue the fabric to the foam? You need to, that's the way office chairs are put together. Otherwise, the fabric will stretch and warp and sandpaper itself against the foam wearing everything out faster.
Now, by the pictures I'll attach, you'll note I glued the foam slab to the foundations and rolled the edges over before attaching the fabric. That was my first mistake. My second was using the old fabric as a pattern for the new. That forced me to pull the fabric together with staples making everything lumpy on the edge and ruining the nice bullnose roundover on the foam that matched up with the plastic back covers. This also made it much more difficult to glue down and keep the headliner foam and fabric smooth during application. Given how nice a roundover I got before screwing up the fabric cover, it's obviously wiser to just glue everything together while it's all nice and flat before shaping it. This said, the dimensions should be about perfect and the new pad should look pretty close to the shape and size of the original when it was new and fit nicely against the plastic backs and not have a gap. The foam I rolled over fit perfectly before I whiffed it with the fabric.
Given my own success at re-stuffing, I figured it was worth buying a new piston for the chair as the old one was leaking, and two replacement arm adjustment parts as mine were broken from David at Crandall Office, even though they didn't normally sell those arm parts. So, it cost me about $110 all told to rehab the chair and keep it out of the waste bin, but I suspect it'll easily give me another decade or more of service. Given the time I spent, if I had actually valued it, it would have worked out to about the same as a refurb from Crandall, so if anything, it proves that buying a refurbished and used Steelcase Criterion from them is a reasonable value if you can't find one cheap and local yourself or aren't inclined to repair yourself. Either way, instead of just going, "Hey! I spent $60 restuffing my 25 year old Steelcase instead of buying a new chair," I wanted to share how given how little I'd found online as to the how of restuffing any office chair, let alone the Criterion, and that you can find replacements for broken parts if need be.
I'll admit, I'm worried I sound a bit like a shill regarding Crandall, but I didn't get compensated squat for mentioning them. I mention them because David went above and beyond the scope of his own business to help me figure out how to fix my sad-sack chair, and dealt with me in integrity, even quickly correcting a shipping error. He's a decent guy, and he offers a decent price with a surprising warranty on a rebuilt Steelcase (under $300) which is a sight easier to swallow than one of these things brand new at over $1000. Given really crappy office chairs that die in a couple years run nearly $100 these days new, and are usually too trashed to buy used... and that even most fancy $300 new office chairs don't last that long. The Criterion's definitely a BIFL item, even more-so with an effective and easy way to replace the foam now that doesn't potentially look terrible (provided you do it the way I propose, and not how I actually did it).
TL;DR: Easily restuff a Steelcase Criterion chair using 2" thick 50lb foam, with the slab cut at a 45° angle and the front side larger than the back. Glue headliner foam cloth and good tweed fabric on top with a drawstring around the edge, and glue the upholstered slab to the foundation, glue the foam bevel, roll the edge over on itself, and pull the string tight. Viola - re-stuffed chair. Also, dollar for dollar, it's almost cheaper to restuff, reupholster and replace parts on a BIFL desk chair for another decade or more of use than it is to buy the cheapest entry level desk chair now. If you need a new office chair, consider trying to get your hands on a Steelcase Criterion as they're easy to repair, rugged as all get out, and easy to re-stuff without looking wonky if you can consistently cut foam at a fixed angle. If you need parts to fix one up or can't fix your existing, Crandall Office Furniture offers refurbished models for a reasonable price if you can't find anything used that isn't a biohazard dumpster fire locally.
