Airflow through openings in a cross ventilated building scale model was investigated in a wind tunnel and by numerical predictions. Predictions for a wind direction perpendicular to the building showed an airflow pattern consisting of streamlines entering the room, that originated from approximately the same upstream area in the undisturbed boundary layer and a direction of the flow into the room dependent on opening location with velocity vectors pointing away from the stagnation point. The measured internal pressure for various opening sizes was not the average pressure on the windward and leeward sides and the airflow rate was found to be a linear function of the local pressure difference across the building.