Research in environmental perception has illustrated that contextual compatibility and building facade ornamentation are important determiners of preference for specific architectural designs. This study extended these ideas by investigating the perceptions of contextual compatibility between two groups when assessing heritage and historic urban streetscapes in addition to testing the significance of the presence of facade detailing (specifically, quoins and a window treatment), rather than massing, in these evaluations. Participants were divided into students with and without a design interest, and then asked to assess four heritage and historic urban streetscape sketches using a unipolar adjectival rating scale arranged into seven ad hoc categories. A factor analysis yielded six distinct scale groups. Subsequently, multiple analyses of variance were executed, demonstrating that the results did not support the hypotheses, although several main and interaction effects were found. When all four independent variables (i.e., design interest, the two detailing variables, and massing) were included, a window treatment main effect, a window treatment by design interest interaction and a massing by quoins by window treatment interaction surfaced across the six factors. (Abstract shortened by UMI.)