The case study deals with problems concerning bringing up existing buildings to present days standard of housing design – expressed more specific: the renewing of bathrooms and kitchens in the more traditional built part of the existing stock of multi-storey housing in Denmark. The solution in this case is a complete substitution of a part of the original building. The new part being a reinforced concrete construction made entirely of large prefabricated elements, including fully fit bathroom-units and closed by a curtain-wall. The case should be seen as an example more than the “final solution” – as a radical way to tackle problems in general, not being locked by standards of doing.