This article presents measuring results of the thermal performance of duo-pitched tiled woodframe roof designs. The roofs have been monitored in a test building, exposed to the outside climate. The experiment was part of a programme to study the hygrothermal performance of highly insulated envelope parts in situ, in order to investigate whether a good thermal quality (U = 0.2 W/(m 2 K)) is achievable with current residential construction practices in Belgium. The results show the effect of wind on the thermal performance of duo-pitched roofs. The measured thermal properties of the roof components are compared to the design values, and related to the wind speeds and directions registered near the test building. The established thermal effects are explained using tracer gas tests to show the pattern of wind driven air flow in the roofs. (c) 2006 Elsevier B.V. All rights reserved.