Modifying a stairway - quick sanity check

Hi. This is one of my quick shout-outs before doing a task - just in case I’m overlooking something I should be considering.

We have a stairway to the unfinished top floor of our house. It is made of three pine stringers and yellowtongue risers and goings. It’s not flash but it was free (long story) and is very solid, compliant and well anchored, so I’m going to clad it and use it eventually. It consists of a lower flight, a broad landing, and an upper flight of 7 or so stairs.

My problem with the upper flight is that the drop to the first stair is hard up against the living room. I want to modify this to provide a small landing - enough for a user to stop and think before proceeding. I reckon having one of these on a previous property saved my life once (another long story) so I want one here.

I have freed up the upper flight and moved it back horizontally away from the junction with the living room floor, and then fixed it back solidly both to the walls and with cross braces (typical overbuild). I now need to add a ‘stair’ at the top and a ‘landing’ at the bottom.

I intend to do the top stair with a box framed with 90x45 structural pine anchored to the existing framework with 90mm bugle screws, and clad it with a riser and going in yellowtongue. The second photo shows this space.

The extended landing I intend just to do with yellowtongue. Essentially it’s a 1200 x 700 x 140 box sitting on the existing landing. I choose yellowtongue rather then timber because it won’t misbehave or start squeaking. First photo show where this box will sit. I’ll double or triple the yellowtongue to give me solid verticals and fix it on top of the existing yellowtongue landing.

So my question is - is there anything I’m overlooking. My two main concerns is that I may be breaking some stairway regulation or that my work may develop annoying squeaks or noises later ?

Thanks
Arron


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