This note summarises our replication study ‘Housing, Health, and Happiness’, henceforth HHH2009, which constitutes an important paper in the literature of housing and slum upgrading. The original authors conduct a quasi-experimental impact evaluation of ‘Piso Firme’, an intervention that replaced in-house dirt floors with cement in Mexico. We conduct a Pure Replication (PR), a Measurement and Estimation Analysis (MEA), and a Theory of Change Analysis (TCA). In our PR, we did not find any major discrepancy with the original study. In the MEA, we generally find the results to be strongly robust to different types of alternative analysis. Finally, in TCA we explore a dimension that was not reported on the published version of the study and found that households with high initial levels of cement-floor coverage benefitted significantly less from Piso Firme’s intervention. These findings are discussed in greater detail on International Initiative for Impact Evaluation’s (3ie) working paper version.