Maximize Your WiFi Signal: The Ultimate Router Placement Guide.
Certain household materials such as metal, concrete, ceramic tiles, glass, and mirrors can block or weaken WiFi signals due to their electromagnetic interference. Metal is the worst material for blocking radio waves, followed by concrete. Glass and mirrors can reflect the waves, while ceramic tiles and metal laths can increase interference. To improve WiFi connectivity, it is recommended to keep routers in open spaces and away from these materials.