Attaching stringers together to form a staircase?

Does anyone know if it is code to attach stringers together to form a staircase? I got a bid to change the layout of my staircase, which will require a steeper descent before the landing. Instead of creating new stringers for the whole run, the bidder wants to take what we have and attach stringers to make it longer.

Another thing is that he cannot guarantee that the rise and run will be the same for each stair, warning that it might be a 1/2 inch off.

Here are some photos:

Imgur: The magic of the Internet


First, where are you located? There may be specifics there to consider.

Second, we are not code inspectors. Check with your code office to see if you need a permit pulled and an inspection for YOUR protection, as well as, the specific info you seek.

In my opinion, if the stringer, in ONE “flight of stairs”, was adequately supported and joined, I don’t see a problem BUT I would want it continuous, as in one piece, when I look at your sketches.

Also, I believe a “flight of stairs” runs between two landings and a “stairway” is made from one or more “flights of stairs”. And, the greatest riser height within any “flight of stairs” shall not exceed the smallest riser height by more than 3/8’’. You appear to be contemplating two “flights of stairs”, with a landing between them.

There, you have my opinion.

I’d check those run dimensions and verify that the incline isn’t in fact too steep. Yes you could sister what’s there, but why? To save money and then to potentially have squeaks? I have a three story that was built with a 7.5/10 staircase. It’s entiely too steep and uncomfortable.

What is your total floor to floor height?
You are showing a total of 16 risers on your drawing. That would be an approx. riser of 6-3/4" based on a 9’ floor to floor.
With a run of approx. 12’-6", you need to check how your headroom will affect the stair opening on the second floor.
Also, changing the riser height on stair flights in between landings is allowed, but not favorable and should not be more than 3/8".

I think you better have your Contractor explain and check a few things for you.
Run/tread width
Riser height
Headroom heights
second floor opening affects

The rise and tread have fairly strict requirements regarding variances, they should all be consistent.