Grooved riser (with glue)
It’s time for something more positive. This part of the stair project went extremely well. In fact, the only thing I had a problem with was the glue getting everywhere, including on my screw gun. The plan is to eventually clad the OSB risers and treads with hardwood, so there the OSB tread has no nose and it didn’t need to be as thick as a typical tread. Maybe I could have overbuilt it, but I already had a lot of leftover ¾” OSB from the subfloor so I used that. I didn’t want the treads to deflect, or flex at the back when you step on them, so I decided to cut a groove in the risers and a tongue on the treads so they’d lock together. I contemplated using the router, but instead I picked up a dado blade set for the table saw, which is awesome.
Riser and tread interlock
I first cut all of my treads and risers to width on the table saw with the regular blade, then cut them to length on the miter saw. Then I swapped in the dado blade and cut a ⅜” deep groove in the risers, ⅜” from the bottom edge. Next I cut out the bottom ⅜” of the edge of the treads, again ⅜” wide. The two pieces fit together like a glove. I wasn’t quite done though. I also cut out the bottom ¼” of the treads, ¾” wide, and cut all of my risers ¼” tall. As a result, both the front and the back of the tread locked into place.
Treads and risers installed
With my careful stringer work completed, gluing and screwing down the risers and treads was a fairly quick job. Every once in a while, something goes to plan, and I’m pretty freaking happy about it. Next step is the landing floor.