The above diagram looks so simple. In residential and commercial construction, the most commonly used rise and runs for stairs are 7 and 11 inches. That yields a pitch line of about 33 degrees (32.7). I have built two staircases for our house. For the first, to overcome a five-foot retaining wall that kept us from being able to circumnavigate the house, I consulted my son and using sine and cosine, he gave me the run and number of steps. See below.
There was a problem, however. I used a 2×12 stringer, and in doing the measurements, I started at the upper corner on top and measured to the lower corner on the bottom. That messed everything up. Consequently, I ended up with an 11 inch run and a rise height of something like 6.4 inches. However, it’s a functional staircase. I was able to sink the footings for this staircase in cement. The former owners used that side of the house as more or less a junkyard. Once the stairs were in we were able to clean it up and lay some gravel, so now it is inviting to the eye.
I am not sure of code requirements here, but I do know that for any staircase it is mandated that all steps be of identical rise and run. That’s a sensible regulation, as it prevents people from tripping over uneven steps.
The other stairs I built were hardly a “staircase”, as I built more or less a horizontal ladder. It’s a rickety thing, but better than the rope that was here when we moved in. The grandkids were very glad to get that structure, as it led to a playhouse up on the hillside. You can see in the photo that I put in one rickety banister which has, oddly, withstood heavy use over the years. (This photo is the old horizontal ladder and the new stringers on either side.)
But I learned a thing or two building that Rube Goldberg thing … in the future, I will always build in the garage and haul the finished product to its site. I struggled mightily using a skill saw on that hillside to make the notches that allowed for steps. It would have been so much easier to do that indoors.
I decided last fall to replace the existing horizontal ladder with a real staircase. I have struggled mightily with it. The problem is my accountant’s brain that wants a straightforward staircase like the one pictured at the top. But that cannot be … the pitch line for the new staircase is 39 degrees, and the stringer is ten feet max … that is, I cannot just run a longer stringer as this new staircase will abut the driveway, so ten feet is maximum.
The wood for stringers has been buried under snow now for several months, but finally we have melting. I brought the wood into the garage yesterday determined to solve my dilemma – what should the rise and run be for a ten-foot span and 39% rise? You would think it would be straightforward, and I bet that people with building skills out there are chuckling about this, but I came up with co*ckamamie numbers and was worried that if I cut, I’d be travelling to Home Depot for more wood.
So, at last, I decided on the following: The rise would be seven inches. I then took one of the stringer boards out to the site with my level, and put it in place, and drew a level line that would serve as a guide for marking the board for stair cuts. That done, I took a small section of stringer I purchased at Home Depot, and used it while squaring with the leveled line I had drawn. Using the 7-inch rise allowed for whatever length the run would end up being, which turned out to be 8-3/8 inches.
Frame it and hang it, I thought. I learned from watching a carpenter on TV to take my square and clamp small pieces of wood to it at the proper marks, and then just slide it down the stringer, marking each step along the way.
The rest, I think, will be easier now that the math is done. I like to tell people that I became a CPA because I could not do much else – I didn’t know how cars ran (still don’t) and everything I have ever built looked like I built it – God forbid I have to work with non-90 angles. But I have gotten better over the years. I sometimes use 22.5 degree cuts in making stuff, which if you notice is half of 45, which then again leads to a square object, all I can manage.
