Bathrooms became common features in buildings around 1920 in line with the introduction of iron beams and reinforced concrete in the floor structures of multi-storey housing, and with the updated legal provisions on housing conditions.

Bathroom floors were cast in concrete – using inbuilt iron supports (I-beams), as shown in the figure to the right, or two-way reinforcement – and constructed in several layers, usually finishing with a terrazzo floor covering and waterproofing layer.

The walls are made of brick or cement-based materials and covered with ceramic tiles, usually from the floor level to a height of roughly 180 cm. Wet room membranes, although a requirement today, were an unknown phenomenon during this period.

Pipe penetrations into the floor will entail either the complete embedding of pipes or the embedding of sleeves, so that the pipes remain clear of the actual floor structure.

Recommended literature in Danish:
Karl J. P. Jensen: Installation af vand (1931) Bygningsdel/Installationer

Grundejernes Investeringsfond, Realdania og Byggeskadefonden