The exterior block of steps needed to be the same concrete colors I used for the base:
VMC 160 Neutral Grey highlighted with 110 Deck Tan
Then tint the area between those two colors with P3 Cryx Bane Highlight
Shade with P3 Coal Black
Finally highlight more with White
The interior has a staircase that I painted in steel colors.
Base with VMC 160 Neutral Grey, shade with Black Grey and Black. Highlight with Light Grey and then White. Tones are added with a mix of VGC Turquoise and P3 Cygnar Blue Base. Using a normal brush, edge highlights are done with white.
Both stairs and steps were weathered like the rest of the building. The rust is a mix of Vallejo 131 Orange Brown and 137 Cavalry Brown. Then the chipping effect is stippled on with blister pack foam and P3 Umbral Umber.