The concept of controlling the radiofrequency (RF) transparency of building wall structures is analyzed in this article with a focus on southern European architecture, where it is demonstrated that some materials have a significant impact on wireless propagation. As such, the integration of frequency-selective surfaces (FSSs) in some building structure arrangements might have few overall benefits. This work provides an analysis of the different elements required to modify the electromagnetic (EM) transparency of building wall layers: 1) different methods to control the frequency selectivity are identified with a special focus given to FSS, 2) some proposals on the integration of the FSS on current and new building structures are provided, 3) measurement results are presented regarding the penetration losses of multilayered wall samples, with and without the presence of FSS layers, and 4) a multilayer EM simulation tool developed in MATLAB is introduced and validated against measurement results, allowing the simulation and analysis of additional scenarios. Results are provided for a frequency range of 800 MHz up to 10 GHz.