Staircase Movement

[thias]

When we moved into our house we found the majority of the downstairs floor joists to be rotten, including the one the the flight of stairs up to the first quarter landing was resting on.

The staircase was propped up whilst a new floor slab was laid and a new wooden frame built under the first flight of stairs before the temporary prop was removed. All seemed well.

Since then, we've noticed the first flight of stairs are quite creaky as they're walked on and the noise seems to be extending to the 2nd flight up to the second quarter landing now as well. Gaps have also appeared along the staircase skirting too. So I suspect we missed something when re-securing them after the new slab was laid.

Can anyone recommend what we can do to try remediate this? We can access the underneath of the first flight of stairs pretty easily from a cupboard below, but to access the underneath of the second would mean ripping off the plasterboard...

 

[conny]

As always, pictures can often give a much clearer idea of the problem.
Can you post some? Both close up and further away are usually ideal.

 

[Deleted member 174758]

Possibly the timber frame beneath the half landing swelled a bit (timber stored outside, house unlived for a while so some moisture in structure, possible absorption of moisture from concrete in the slab you mentioned) and has now shrunk slightly as the house has dried out with heating on. Is anything loose under the stairs? As Conny says, photos will be a great help

 

[^woody^]

Lots of moisture from a floor slab can affect the timber in the stair strings or treads. As can twisting the flight from propping or dropping it after. As can cranking the heating up in autumn.

I would suspect that if the creaking does not settle down after a while, then the only option is to open up the underside and re wedge the treads/risers