And I think I would leave risers off deck stairs. Keep em nice and open.
Open risers have become illegal in new construction most places in the last ~10 yrs.
I guess because infants might crawl through and fall.
Open handrails are a thing of the past for the same reason.
The vertical bits under the treads; labeled ‘1’ in this diagram
They stop Freddy Krueger and his ilk from grabbing your ankles as you go down the steps.
Turn the ruler around dear 
But people that do, know enough to ask for rough cut. 99% (number just made up) of people who look for lumber would much rather have smooth, planned lumber rather than rough cut wood that leaves you with splinters, regardless of the exterior dimensions.
Standard lumber dimensions have been around for a long time. It can be confusing if you’ve never encountered it before, but most folks pick it up rather quickly and most building plans are very clear on what is needed and how to measure. It does kind of amaze me that an adult in our society could not know about this, but my sample of people could be pretty biased.
HOLY SHIT! My lumber 26 inches!
[AP]*Yeah baby! *[/AP]
They are at lumber mills. Home improvement centers do not carry rough stock. Anyone savvy enough to know about rough stock will not be asking for it at Lowes, et. al.
That’s a good one.!
Maybe I’m missing something, but that doesn’t make any sense.
He has his step sitting flush with the front edge of that part of the stringer giving him 3/4" gap in the back. A 1" riser goes in there so it all fits… but now the next step up has 10 3/4" to cover because of the extra thickness of the riser.
Uh Oh!
Risers on a plane!
Lame, I know.
[Channeling Rodney Dangerfield]What am I invisible? I can’t get no respect![/CRD]
psst
So you’re sportin’ wood, just not a full 10 inches?
Welcome to the club. 
I’m willing to wager his boards weren’t 1-1/2" x 9-1/4 “,
they were 1-1/2” x 9-1/2".
Thank you, i’ll be here all night.
It’s amazing the lines you have the opportunity to come up with when you bartend at a VFW hall.
Or an escalator. :eek:
Like a frightened 2"x10"!
I use two 2"x6"s (2 at 5 1/2" = 11") with a 1x riser, with a standard deck board space for drainage, leaving a +1/4" -1/2" overhang, never a 2"x12".
Why? A 2"x12" will cup like a motherfucker!
I’d never use 5/4 either, even with a central stringer, they’re just too springy for steps.
Oh yeah, you did get pressure treated stringers, right?
CMC fnord!
No, I saw your post, but I understood it. Though you may have cupping issues with a board that wide on a porch step, the geometry works out. I responded to Squink because the math didn’t quite work out on his post.
Indeed. An open riser would fail the 4" sphere test- See IRC 311.5.3.3, 312, LSC, et. al.
Wow, even on the few steps leading from a deck to the ground? I had heard the 4" rule for handrails before but didn’t know the riser part.
And I am an adult who wouldn’t have known the true measurements of a 2x4 without having done some volunteer work with a home repair group.