The curved roof of the building is made of solid zinc with just a few tenths of a per cent of titanium and copper. As the metal ages, it acquires a slightly darker patina.
The vertical windowless elevations are made of aluminium, which is resistant to the maritime climate in Helsinki. They were sandpapered by hand with horizontal strokes, giving the aluminium a surface that refracts light.
There are reddish surfaces on the south and north elevations of the building. These are made from acid-reddened textured brass, treated with heat and chemicals.
The building’s big curved glass wall is made from Reglit glass u-blocks, which are mainly used in industrial buildings. The greenish element has been removed from the building’s glass walls and gallery windows in order to ensure that the light entering the building is natural daylight. Most of the glass surfaces are sandblasted, using aluminium oxide or silicon dioxide instead of sand. This creates a prismatic surface that refracts the light beautifully. The other glazed walls are steel curtain walls.
The walls and ceilings are of white plaster, with the aim of creating tranquillity and simplicity.
The floor is dark grey, almost black, concrete. The high curved concrete wall of the foyer is concrete cast in a horizontal board mould and painted white.
The walls of Kiasma Theatre are reddish plywood. The control booth is upholstered in fabric that gives the impression of dark blue velvet.