Extending the landing

[noseall]

Do you mean to fit a new joist where the blue line is and board over the orange gap to make the upstairs hallway wider?

View attachment 338538

Correct. I misunderstood in my first post.

It could be faffy where his proposed new floor strikes the rise of the quarter turn stringer. That's why I asked. Its not obvious in the photo.

 

[robinbanks]

I reckon you'd get away with doing it off the newel; there's not a lot of dead load being added, the stairs already are proven to carry the live load and despite the hall getting wider, I don't expect the new bit of floor will carry any exceptional load that isn't borne mostly by the old floor anyway, given the small width increase

Take a picture from the other end of the upstairs handrail, and one looking up the downstairs handrail

 

[noseall]

I reckon you'd get away with doing it off the newel;

Off the side of the newel and with a chunky spacer or two - possibly.

 

[AP25]

I reckon you'd get away with doing it off the newel; there's not a lot of dead load being added, the stairs already are proven to carry the live load and despite the hall getting wider, I don't expect the new bit of floor will carry any exceptional load that isn't borne mostly by the old floor anyway, given the small width increase

Take a picture from the other end of the upstairs handrail, and one looking up the downstairs handrail

 

[noseall]

View attachment 338587View attachment 338588
View attachment 338590

I'd say you'd be ok extending to within say 50mm of that newel, so that once everything is plastered up, you still have room for your fingers (handrail).
Luckily the stringer does not descend with the stairs.