While field measurements of pressures on real buildings have been accomplished, such measurements are both expensive and time consuming. Predictions of facade pressures for specific buildings can be made during the design process by testing a scale model of the building in a boundary layer wind tunnel and by combining the wind tunnel data with environmental data dealing with wind speed and air temperature. These wind and temperature data are then used in conjunction with known or assumed permeabilities of the exterior wall and of building interiors so as to determine internal pressures from stack-effect. From the difference between external pressures and internal pressures the net steady-state pressure is then determined and added to the fluctuating component of wind pressures to determine the total pressure to be resisted by the facade.