I have an internal wall in a 1980 flat conversion that appears to be concrete sheets with breeze block colour/style material sandwiched between. On hardness; I can't scratch or crush it with a fingernail but can comfortably eat into it with an old screwdriver. Total wall thickness is about 160mm or so. After chasing a channel the 1cm concrete layer is very consistent and doesn't look to be plastered on to the internal material, it looks more like a bonded sheet.
Can anyone identify what type of wall this is? Was it a typical build material for creating internal walls in the late 70's, early 80's?
I ask the question because I need to secure fixings into it to hang a
20kg glass showerscreen which provides 4 fixing points along the hinge on which the glass hangs.
I am almost tempted to run bolts right through the wall and use sunken nuts and washers on the opposite side - but that might be overkill, and fiddling about with threaded rods might be a pain.
What would people here recommend?