Teaching practices and social relationships in schools are significantly influenced by the prevailing building structures. This aspect is particularly relevant when it comes to the modernization of historical school buildings. But how can modernization be planned to avoid misdevelopments and enable sustainable strategies in the long term? Maja Lorbek presents scenario development as a planning tool for school modernization. By examining several scenarios—such as that of a controlled school market, which describes a school system without a state educational monopoly, or that of a differentiated school as a representation of the consequences of previous practices—the viability of the tool is discussed.