The indeterminacy of the domestic space is one of the main trends in flexible housing design. It involves the possibility of using the rooms in a dwelling in multiple ways that are not determined by the architect. The views of non-functionalist housing are more present lately, but still forbidden in the Spanish social housing market, where regulations stipulate a strict functionalist housing plan. However, there is a premodernist example of this strategy in Madrid: the Casa de las Flores (the House of Flowers), a rationalist building from 1931 with a neutral plan of indeterminate rooms. This study comprises a series of interviews with the users, photographs, diagrams and new drawings that show how people use their apartments. The aim of this research is to assess the validity of indeterminacy as an architectural response to social changes in Spain, with a view to its introduction in future housing developments.

Keywords: architecture; flexibility; indeterminacy; social housing; Spain