As apartment buildings age, the exterior walls usually have to be repaired after about 40-60 years. In the case of exterior wall renovations of apartment block, the old facade is usually completely renovated and the new surface is based on plastering. Plastering is used as a outermost facade surface especially in major overhaul cases, where energy efficiency is improved by increasing the thickness of the insulation layer. However, plastering can add surprising increment the radio signal attenuation caused by the exterior wall. The reason for this is the iron mesh used to support plastering. That mesh attenuates the signals of wireless systems, especially at low frequencies. In this study, it has been shown that the plastering mesh acts as a high pass filter and can double the wall overall attenuation at frequencies below 1 GHz used by cellular networks.publishedVersio
