In a city as dense as Beirut, where public spaces are scarce, securitized, and feared, the project Protocols for Beirut’s Unbuildable Lots maps potential spaces for non-sectarian commons. Building upon the theoretical statement Untangling Beirut’s Sectarian Geographies, which tackled how sectarianism spatializes in Beirut, the thesis identifies, categorizes, and catalogs Beirut’s unbuildable lots. These sites, anomalies in the urban fabric that escape sectarian development, are too small and awkward in shape to be constructed by law. Paired with material, legal, and logistical tactics, this non-exhaustive atlas of spaces is created as a toolkit for Beirut’s dwellers to reclaim agency as actors of their built environment. Different insertions meander around the inconstructibility of the sites, leveraging existing elements and resources through non-invasive structures. By retrieving and making visible vacant and municipal land, they answer the need for common civic spaces. Navigating sectarian geographies and the intricacies of infrastructures, and real estate, the designs become secular and mundane structures of daily life. Within these divided geographies, dwellers negotiate to find space for alternative collective narratives on the fringes of sectarian planning. Through this, the lots – representing around 1% of Beirut’s surface – emerge as interstitial openings for potentially disruptive mobilizations, creating thresholds within the divisions in which the Lebanese operate.