This research addresses the necessity for an effective toolkit to assess damp and mould risks in UK housing, with the objective of ensuring healthy living environments. It proposes a pragmatic decision-making tool developed through soft systems action research involving practitioners and decision-makers. The UK Housing Ombudsman mandates landlords to assess damp and mould risks without defaulting blame on occupants as minor mould can be cleaned, serious mould poses health risks. The pre-2004 binary fitness standard is outdated, and the current Housing Health and Safety Rating System (HHSRS) is complex, prompting calls for a simpler assessment method. Surveyors require a communication tool to effectively assess risks from damp and mould, bridging technical inspection and health implications to guide decision-makers. The study employed soft systems action research and the LUMAS framework to incorporate human factors and complexity in housing inspections, involving 18 practitioners and asset managers in focus groups to validate the toolkit. Inspired by subsidence crack assessment, a risk category table based on mould coverage and remediation strategies was created, facilitating practical on-site evaluation and communication to managers. Mould can occur without structural dampness, often linked to behaviour, fuel poverty, and misused heating/ventilation systems, highlighting the need for ongoing monitoring and occupant engagement. This was field-tested in social housing, proving effective for upward communication of risk and resource allocation, balancing mould removal and safe occupancy decisions. Future research will focus on integrating data from temperature and humidity monitoring to refine risk assessment and guide heating and ventilation adjustments for healthy homes.