Why is there no Wi-Fi in the bathroom?

It's a small room, often in the middle of the home, and yet the podcast buffers and the video call drops the moment you close the door. Bathrooms are one of the most common weak spots, and the reasons stack up.

What makes bathrooms so hard

• Tiles on masonry. Ceramic tiles on a brick or block wall, with the adhesive and render behind them, add up to a thick, dense layer, often on several walls.
• The mirror. Mirrors have a metallic coating that reflects radio waves like it reflects light. A large mirror on the wall facing the router works as a shield.
• Pipes and fittings. Water pipes, radiators and metal fixtures scatter the signal.
• Water. Water absorbs 2.4 GHz especially well: a full bathtub, wet walls, even a person standing in the shower.
• The closed door. A door is often the easiest way in. Closed, it forces the signal through the walls.
• Windowless and interior. Many bathrooms sit in the core of the home, surrounded by other rooms and service shafts.

What helps

1. Look at the path, not the distance. A bathroom right behind the router's wall can be worse than one two rooms away with an open doorway in line. Moving the router so it sees the bathroom door, not the tiled wall, often helps more than anything.
2. Mind the mirror. If the router sits on the other side of a wall with a large mirror, move it along that wall a little. The angle matters; see Wi-Fi and walls.
3. Try 2.4 GHz for the bathroom. It passes tiles and masonry better than 5 GHz. See 2.4 GHz vs 5 GHz by room.
4. Cover the hallway outside. A mesh node in the corridor next to the bathroom and bedrooms usually covers all of them. Never put a node or extender inside the bathroom: humidity and electronics don't mix well. See where to put a mesh node.
5. Test with the door closed, because that's how the room is actually used.

Is it worth fixing?

If it's only the bathroom, and only for background music, a cached playlist or podcast downloaded in advance is the simplest fix. If the bathroom is weak because the whole side of the home is weak, fix that side, and the bathroom will follow.

See where the signal stops

WiFi Heatmap maps the rooms around the bathroom and shows whether the drop happens at the tiled wall, at the door, or further back in the hallway. That tells you whether to move the router, add a node in the corridor, or simply leave the door ajar.