This paper summarizes the analysis of the fire that destroyed Neutra's VDL Research House I, located in California, in the spring of 1963. The objective of the work was to determine what elements of design and construction lead to the outcome, establish if a well-designed building with a standard fuel load would have resulted only in local damage and what specific aspects laid at the source of the massive damage. The investigation consisted of three distinct steps: structural analysis, fuel load and ventilation analysis, and compartment analysis. All these combined gave the maximum possible duration of the design fire having an ISO temperature evolution. After performing a parametric study for fuel loads and ventilation conditions, it was determined that the fire that brought down the house was most likely a post-flashover fuel-controlled fire. One of the main conclusions of the investigation was that, had this fire been limited to the room of origin, the outcome would not have been possible. Failure of compartmentation is most likely considered to be related to constructive detailing.