The stairs are actually very tough. They're white glue and foam core. I've stepped on a stair case and it survived.
I have a blank building with lots of stairs, windows and doors that I call the building commission. I can refer to it for standards. My floor height is 2.25 inches, which equates to 12 layers of 3/16 foam core. Twelve is easily divisible by three and my stair segments are built of three repeating pieces of foam core that leave a gap every step so that I can slot in a figure base if they finish their move mid-climb.
I do two styles, one steep and one gentle. I employed both styles on Laod Bhang Fireworks, to make it sort of a jungle gym for precarious shoot outs.
I do plan to finish the inside of the Golden Pagoda, including railings, but I had already spent so much time building it that I was a little tired and I wanted to play.