Fastening staircase concrete/brick wall

[stayfrosty]

I'm going to install a staircase against a wall. Due to some obstacles on the wall, it will be about 45 millimeters from the wall. My question is how best to attach the stringer to the wall. Should I first attach a beam to the wall and then the stringer to it, or should I attach the stringer directly through the beam that acts as a spacer?

I suspect that the wall is made of masonry lecablocks since the other walls have been.

There are such lightweight concrete screws, but are they suitable for this?

 

[Matti_75]

I would make sure to attach a bracket first that is secure and then screw the stairs into it.