This thesis examines the purpose and implications of the so called attefall rules. A discourse analysis of the government bill which the attefall rules is based on shows that they are a neoliberal reform with the purpose of providing housing through the furnishing of additional apartments in single family homes and the building of accessory dwellings in private gardens. They deregulate said measures as well as the building of accessory buildings, extensions, and dormer windows. Ten interviews with officials mainly in the Stockholm region and the study of two judgements provided the implications of this reform in practice. While the reform has provided more opportunities for houseowners and more agency for officials, unexpected issues have also arisen that the current regulation is ill equipped to solve. Attefall projects are by default exempt from the planning that governs all other development in a municipality, meaning that municipalities have little control over them. As such, the established system cannot compensate that for which the attefall reform has not accounted. While interviewees are mostly positive to the attefall rules in principle, in practice they are underdeveloped. The attefall rules illustrate the risks of underdeveloped deregulation.