Often the structural engineer and the building services engineer need to know wind pressures that occur on the facades and the roof of a building. The structural engineer is interested in the wind forces on the building, the building services engineer is interested in the pressures and underpressures at the air intake apertures and outlet ducts of the mechanical ventilation. An insight in to the pressures can be gained by applying points of measurement to a scale model and carry out measurements in the wind tunnel. If so desired an extreme values analysis can take place which can be of importance to the structural engineer.