Natural ventilation can be used to cool buildings during many months of the overheated season. A significant design problem arises in ventilating rooms which have only one external wall and, therefore, cannot be normally cross ventilated. Architectural projections called'wingwalls' can be used effectively to ventilate these rooms. This paper confirms the benefit of wingwalls from airflow measurements in a full-scale room with and without wingwalls. Alternative design strategies for incorporating wingwall features in residences are also described.