Fire-damaged houses are often refurbished for further use. In some cases occupants complain about odours from the fire in the refurbished houses. Experimental box fires and a field study of refurbished houses were undertaken to investigate the problem. Concentrations of combustion products from fires in the experimental box were measured for up to 30 days afterwards and the decay of concentrations of the combustion products was calculated. The decay was faster in humid conditions than in dry conditions. There was a correlation between the boiling point of compounds and the decay constant. Some compounds remained in higher-than-normal concentrations for several hundred or several thousand days. Field studies of refurbished houses showed results consistent with the experimental study.