Surface as an Experiment

Empty, raw and misty space. Høyblokken. All is left is pure structure. The rough concrete ceilings, the colossal pilotis, the abstract sandblasted, wall-fixed art and the Conglo-concrete floor. No windows, partition walls, flooring, fixtures, air-ducts, furniture, equipment, office supplies and people. This “prenatal” version of the building, being disentangled from function and use, appears like a rough working model of a building project in process.

Høyblokken - surface analysis map
Høyblokken – surface analysis map

The “naturbetong” technique invented by Erling Viksjø, is implemented on exterior and interior walls and columns, both as an overall surface-treatment technique and as a strategy for incorporating artworks into the building.

surface imprints
Surface imprints

There is a fascinating ambiguity embedded in Viksjø’s moralistic denunciation of stone cladding on one hand, and his introduction of decoration on another. In his text “Fasadebetong” from 1951, Viksjø describes the result of one of his experiments: “It occurred to me that where the cement-sludge membrane dissolved and the aggregates appeared, the true structure of concrete was revealed”. He uncovers what can be described as the essence of the material, the river-gravel hidden under the layer of sludge. But on a more fundamental level, the technique seems to blur the structural properties of the elements rather than clarify them. The river gravel is shiny, and the walls can at times, under special light conditions, be perceived as being made of a shimmering fabric. The numerous artworks in the lobby and the main stairway, resembling tapestries, woodcuts and canvas art typical of the modernist era, contribute to a “flattening” of the wall. Viksjø equates his technique with that of the artist, comparing the sandblasting machine to a pencil or an engraving needle. The nearly equal amount of untreated and treated surfaces, and the thinness of the sludge membrane being exposed by the process, suggest that the pilotis consist of thin, fragile layers, risking to crack or being unveiled.

Viksjø is trying to uncover the underlying essence of a material through the act of blasting. Paradoxically the destruction of the building helps construct a clearer picture of it.surface


Naturbetong is the name Viksjø gave to his method of casting and machining of concrete to obtain special surface effects.

naturbetong / surface model

The casting method means that the formwork is first filled with aggregates of various types of single and gravel, usually round polished river gravel. Thereafter, the cement mortar pushed into the formwork for all voids between the filler material is filled. After the casting has hardened sufficiently long will the formwork removed, and concrete is sandblasted into the stone is clearly visible on the surface. The method thus differs from traditional concrete production, in which the aggregate is mixed in with the sand and cement before it is cast.

naturbetong / manual
naturbetong / manual

images + drawings:
Roman Kekel

Fasadebetong – Erling Viksjø, Byggekunst, 1951
Blasted Building – Erik Fenstad Langdalen, 2014