The relationship between users' behaviour and the built en vironment is shown in a conceptual model of the built en vironment. The ways in which theme relationships affect the model is illustrated on a study of jointly used spaces. Two office buildings are 'appraised within the framework of the model. In the analysis of user responses to the ques tionnaires, relationship between users' level of satisfac tion with their office environment and their position within the organisation, type of work, sex, period of buil ding use, degree of familiarity with the building and of sensitivity towards environmental factors i.e. heat,light, noise and smell are examined. Discrepancies found between planned and actual use of the buildings are discussed. In the light of the results, suggestions are made to modify the earlier designs.