With the support framing in place it was time to add the floor in 2/3 of the shop area. The other 1/3 would await framing of the low-clearance corner.
I had scored 12 sheets of tongue-and-groove 3/4” construction ply off Craigslist. I was a bit worried that the ragged-looking tongues and grooves would require time-consuming rework in order to mate but that turned out not to be an issue—a simple pass with a wire brush and hand saw took care of the minor defects.
I started at the support structure’s highest-clearance (cripple-wall) edge. I dry-fit the first run of sheets, facing the tongue toward the support structure’s outside edge and then trimming it off. I aligned the short (non-T&G) edges of the sheets at joist midpoints, applied construction adhesive to the tops of all joists and the cripple-wall edge joist, then screwed everything down with star-drive deck screws and my cordless impact driver. That was way easier and much less wrist-jarring than using my cordless drill/driver, but also much noisier—I knocked off early that evening to spare not only my partner upstairs but also the neighbors whose uninsulated house wall is 4” from ours (hey, this is San Francisco!) and who watch TV on their basement level.
With a day’s delay before installing the second run I learned that I hadn’t been liberal enough with the construction adhesive (Loctite PL Premium – good stuff!)—two areas under the first run have squeaks that I hope to fix some day. Not the way to cheap out on materials! I tripled the adhesive coverage after that—no more squeaky spots.
I added the second run, offsetting its sheets half their length (48”) to avoid 4-way joints. To firmly mate the T&G joint without crushing the grooves on the other edge of the sheet, I used a sledge driving a scrap 2×4 flat-wise.
(Note that the heavy plaster “wedging” table, precariously perched on a single diagonal strut in an earlier photo, is now supported much more robustly, though still temporarily. No worries with my head under it while driving the deck screws.)
For the third and final run, up against the far wall, the direct sledge-and-2×4 approach wasn’t going to work for mating the 3rd-run tongues with the 2nd-run grooves. I fashioned a “sledging jig” using a 5’ long 2×4 rail with short blocks attached to each end. At one end the block is a piece of 3/4” ply screwed to the underside of the rail, to sit flush against the back edge of the sheet being driven—kind of like reaching your arm across a table and hooking your fingers over the far edge. This required several inches of depth beyond the sheet edge, but fortunately the adjacent wall has open stud bays. If that wasn’t the case, I could have attached an angle-iron with an edge extending 3/4” below the bottom of the driving rail. At the other end of the jig I screwed a 2×4 block to the top of the rail, for driving with the sledge. The jig worked like a champ—the 5’ rail length gave me plenty of sledge-swinging room, and the T&G joints between runs 2&3 seated just as tightly as the 1&2 sheet edges.
A strip of 3/4” ply provided a fastening surface along the stud wall along the back of the third run.
Wood filler applied in the seams and (many) defects—this is C/D ply, nothing fancy—then wet-sanded and dry-sanded:
After 2 coats of Kilz-2 latex primer:
PowerPoint “photo-simulation” of intended color, for consultation with the client (my lovely partner, who has the ceramic studio with the wedging table). I made a “slide” from a photo of the white-primed floor, drew its outline using the poly-line tool, filled with solid color set to partly transparent (you can see the “ghosts” of the tools at right showing through). We sat together and tweaked the color picker to approximate a desired shade, then headed to Lowes for a color chip and a few gallons of floor paint.
Temporary ramp for rolling the kiln, work table, rolling-base power tools, and other heavy stuff up onto the 2/3 of the floor that’s completed:
Now to finish the “shallow end”...
-- Accomplish the great task by a series of small acts. (Tao Te Ching / Lao Tzu)