The Hydro-blocks were built in 1955, also designed by Selmer. They are three-storied blocks made of concrete and brick, with slate clad saddle roofs. There are two flats laterally inversed around the stairwell, and two stairwells in each block, something which provides 36 flats in three blocks. Each flat is comprised of a kitchen, living room with outdoor balcony, bathroom and two bedrooms. The blocks are south-facing, with the living room and balcony facing the sun and the view. The three residential blocks underwent an exterior renovation in the 1990s. At this time a number of changes occurred, for one, the flats were given larger balconies. The original architectural style, along with the plan solution, can be viewed at this website: Boligprosjekter i Norge.