Will a regular screed support a staircase?

[Kernow]

Starting to think about getting insulation down ready for screed. we have the following floor build up:

 

100mm reinforced slab

140mm pir

60mm liquid screed

porcelain tiles floor covering

 

Question is will the screed/insulation be strong enough to take the staircase and newel post weight or will added support be required? Just a standard staircase, nothing fancy. 
 

If it needs supporting what’s the best way to be this? Replace PIR with something like an XPS500 or is there an alternative solution?

Thanks

[Redoctober]

@Kernow I don't know for sure but would have thought any additional support - if required - would have been factored into the plans / building notes.

 

This is a list of our floor build up from the top down and have had no issues with our staircase.

 

limestone  tiles - 22mm

65mm self leveling sand/cement screed ·

100mm Kingspan Thermafloor TF70 (or similar and approved) rigid insulation board. 

150mm thick concrete slab designed by engineer.

[markc]

Unless you are intending a massively heavy single spine staircase then you have nothing to worry about.

let’s assume the staircase weighs 100kgs plus 2 people at 100 kgs each, total 300;split between 2 stringers so each stringer (foot or wall mounted) takes 150 and that is split between top and bottom (unless both people are on the bottom step).

now take a 3 seater sofa with 3 people, say 350kgs split between 4 legs. The loads are fairly similar and you wouldn’t worry about the sofa.

[Kelvin]

Our staircase is supported by two thickening points in the concrete slab. Still not 100% confirmed how we’ll build this up but probably with blocks. 

[nod]

Easily 

[Mr Punter]

I have had an engineer spec some special grout under the newel of a stair in a commercial building.  I didn't bother doing it as the floor was concrete and the stair was only timber.