“stairs” part 2: let’s try that again and again
If you need to catch up, click here to read “stairs” part 1: stringer structural stupidity.
A few years back, when I was framing the basement, I had a large load of 2×4s delivered from Smoot Lumber in Springfield. Some of them were warped beyond usability, and I set them aside in my junk pile. My estimation of lumber quantity was low, and I had to make several trips to Lowe’s and/or Home Depot to augment. Spend any time buying lumber at Lowe’s and/or Home Depot and you’ll find a lot of twisted wood. I guess it’s cut and packed while still a bit wet, and once they cut the straps at the store, the pieces dry out and warp.
I was obsessed with finding quality lumber. I’d dig through the stack of 2×4s, piling the bad pieces in the aisle, looking for the elusive straight pieces, which always seemed to be at the bottom. Once I’d found enough, I’d have to re-stack the bad stuff to clear the aisle. I’d load the truck, take it home, and unload it into the basement. The next day, I’d find that a bunch of the pieces had dried and warped over night. It was only straight in the store because it was at the bottom of the stack and hadn’t had a chance to dry out.
Needless to say, my junk pile grew.
You might think all of that experience would have been in the back of my mind while considering 2×12s for the stair stringers. And, you might also think I’d take seriously the warnings I read about dimensional lumber for stringers. Take, for example, the following picture, from page 34 of Building Stairs, from Taunton’s For Pros By Pros series, showing where shrinkage can occur. In addition to shrinkage, the “teeth” of the stringers can warp to the left or right.
What can go wrong?
Did I take all the warnings seriously? Well, if you think so, then you haven’t been reading closely. Remember?
I’ll cut to the chase. Yeah, both of those things happened. On the bright side, I’m not moving quickly, (I cut the initial stringers in July of 2006, and replaced them, as detailed below, in April of 2008), so the problems became apparent before I finished the stairs. Also, the emotional attachment I had to the original stringers had mostly evaporated by the time I switched on the reciprocating saw to cut them out.
What, you may be asking, was the solution? Well, Building Stairs didn’t have that nice little picture just to taunt me. They offered a more stable alternative involving plywood and a lot of glue. The problem is, stringers are usually pretty long, and pretty thick, and plywood comes in 4×8 sheets that are only 3/4″ thick. So, I’d have to laminate several pieces together to create the board from which I would cut the stringer. In the photo below, the longer pieces are 8′ long, and the shorter are 4′, giving a 12′ length. And two layers gives it a 1.5″ thickness (which, if you’re not familiar with dimentional lumber, is actually how thick the 2″ edge of a 2-by is). Overlapping the joints gives strength.
Jigsaw puzzle
A gallon of Elmer’s carpenter’s glue, two dozen clamps, and 24 hours of dry time later, and I had one stringer. Repeat. Repeat again.
A few clamps
Once the laminated boards were ready, I trimmed the edges, then marked and cut the stringers. And it is will no small amount of embarrassment that I tell you that, after having measured and cut the original three stringers, I cut all three of the new stringers wrong. It was only off by a half an inch, but, believe it or not, your feet can tell the difference. And so can my pride.
What did I do? Repeat. Repeat. Repeat.
Crisp and clean (and correctly cut) stringers
Version 2 of the rough stairs have risers and treads made of 3/4″ plywood. Unlike stairs v1.0, This is a permanent underlayment to which the finish risers and treads will be attached, adding strength and rigidity to the structure. I also left a rather significant gap on each side for installation of the skirtboard.
Was all that work really worth it?
Next on “stairs” – finish anxiety.