Stair step dims according to code

[mark]

Greetings All, I am wondering if there is a short set of rules for residential stair tread heights. In a nutshell, we had a second floor added a couple of years back. The stairs are just site-built plain old utility grade 2x treads that are held by nails and construction adhesive. The flooring at both the bottom of said stairs and top are now finished, so I would like to pretty up the stairway. I know there are certain dimensions to adhere to pertaining to tread height, depth and the max variation from tread to tread. Is this something covered by a national code, or does it vary by municipality? An architect (student) told me allowable tread height is from 7" to 7 1/2" and no more than 3/32" variation in tread height over the run of stairs. I plan on having to remove the 2x treads and hope to use the existing stringers. I have a thickness planer, so I can pretty much make any thickness product necessary to conform to code. Thanks to all who are able to help, Mark

[Mikepier]

The usual rule of thumb is 7-11, meaning 7" riser with 11" tread, but you can tweak the numbers a little if you had to. It definately should not be more than 8" riser.What is the riser height now? You could probably just rip out the 2X and put in premade oak treads.

[mark]

The usual rule of thumb is 7-11, meaning 7" riser with 11" tread, but you can tweak the numbers a little if you had to. It definately should not be more than 8" riser.What is the riser height now? You could probably just rip out the 2X and put in premade oak treads.

As is, I have an 8" tread height, that's why I plan on pulling the treads instead of just topping with something thin. I have a lot of leftover 3/4" T & G flooring which I'm considering using.

[HeyBub]

The big reason for no variation in tread height is muscular expectation of where the next step will be. If your body doesn't find the step where it expects, there's an excellent chance of falling.

[DanG]

Current code is as your student said. I think the current maximum is 7 3/8 rise. If you have an existing stair it is a bit different. I'm really lost by some of your comments. If you keep the existing stringers how can you change the riser heights? IF the existing risers are 8", they will still be 8" if you do the same thing to each one. Riser height is a function of floor to floor measurement divided by number of risers. The thickness or thinness of tread boards will not change any of the issues except the bottom riser.

[dpb]

mark wrote: ...

Problem is, as DanG points out, simply changing out the tread material doesn't affect the between-steps riser height except for the top and bottom two treads so you'll still have 8" rise on all the intermediate steps and an uneven step at the top and bottom which is even worse than a uniform 8" overall for tripping hazard.

To fix them correctly will require either recutting the stringer or at minimum trimming/shimming. But, changing the height will also end up changing the run given a fixed overall height.

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