Microwave reflection coefficient measurements at 1.9 GHz and 4.0 GHz are given for a variety of typical smooth and rough exterior building surfaces. The measurements are compared to theoretical Fresnel reflection coefficients using Gaussian rough surface scattering models when applicable. Individual multipaths are resolved temporally using a spread spectrum sliding correlation system, and spatially using directional antennas. The measurement test cases included walls made of limestone blocks, glass, and brick. The results indicate that the Fresnel reflection coefficients adequately describe the reflective properties for the glass and brick surfaces. The rough stone wall measurements are shown to be bounded by predictions for a smooth surface model and a Gaussian rough surface model. The results of this work can be used to estimate reflection coefficients in ray tracing algorithms for propagation prediction.