Question & Answer: Which of the following building materials restrict wireless signal propagation?…..

Elevators blocks wireless signals in a great extent.

Tinted glass also restrict wireless signals.

Concrete floor and walls can easily penetrate wireless signals, but if walls are thicker or reinforced concrete used, then there will be signals drop

Metal ductwork also have possibility to restrict wireless signals propagation

Metals have high range of interface level, so steel door also can restrict the signals.