In this paper, we investigate typical glazing structures and their radio frequency signal losses at all the frequency bands considered for the fifth-generation (5G) cellular mobile communications from 1 to 95 GHz. The signal loss through glazing is one of the significant factors in determining indoor signal coverage from outdoor base stations. Nevertheless, the radio frequency properties of glazing structures are typically not considered in the industry. Our investigation includes everything from single panes to triple glazed units both with and without low-emissivity coating(s). In total over 50 glazing examples are considered. The signal losses are examined in two steps. First, the radio frequency transmission loss is measured for a few examples at frequencies from 1 to 95 GHz and a simulation method for calculating transmission for a multi-layer slab is validated. Second, the simulations are used to analyse all the glazing examples as a function of the frequency, incident angle, and polarisation. The dependency of radio frequency losses on the thermal transmittance U-value and the glazing structure is analysed.