Here's a good picture of the lower stair
landing. If you notice the building plans called out for a structural
beam, even though it doesn't make much sense to me. I've been building
stairs for quite some time and the engineer could have installed two 2 x
6's, even though that would have been overkill also, but what do I know.
Most stair landings that I have built in the past have been built
entirely from 2 x 6 without any type of structural beam, especially on a
landing this size.
Here's a special note to any architect or engineer. Using different
sized floor joists and beams, can create a wide variety of problems. I
truly believe that things like these are simply put in to justify
someone's job and actually don't serve any purpose at all.
I'm not blaming the engineer, because the City Building Department could
have requested it. I don't even want to get started on that one, like I
said, maybe there's something I haven't learned yet.
Split Level Stair Framing