Where to put the router in an apartment

Apartments are small compared with houses, so it seems like one router should be plenty. Often it is. But many flats have a bedroom or a study where the Wi-Fi is poor, and the reasons are specific to how apartments are built and where the line comes in.

The line enters at the wrong end

In most apartments the socket for fibre or DSL is by the front door, in the entrance hall or on the nearest living room wall. That's where the installer leaves the router, at one end of the flat. If the bedrooms are at the other end of a corridor, the signal has to cross every wall and doorway in between.

Moving the router to the middle is the biggest improvement in most flats. In a corridor layout, the hallway halfway along is often the best spot in the apartment: every room opens onto it, and the signal reaches each one through its own doorway instead of through several walls. A long flat Ethernet cable from the socket to the new spot does the job.

The layout and the walls

Corridor flats, long narrow layouts and L-shaped plans put the far room at the end of a straight line of walls. The fix is the same as above: bring the router toward the middle, where the distances even out.

Not all apartment walls are equal. Partitions between rooms are often plasterboard or light brick and cost little. But many buildings have structural walls in reinforced concrete, sometimes running right through the flat, and in NIST's lab measurements 20 cm of reinforced concrete cost about 31 dB at 2.4 GHz, which leaves roughly a thousandth of the signal. One wall like that can do more damage than all the others together. A lift shaft next to your flat is a metal box and blocks almost everything behind it.

To find out whether a wall like this is your problem, take a signal reading a step before it and a step after it. A drop of 15 dB or more in one step means that wall is the barrier. What blocks Wi-Fi at home explains how to read it, and how to check Wi-Fi signal strength on iPhone how to take the reading.

The neighbours

Above, below and on both sides, every flat has its own router, and many of them use the same few channels. On 2.4 GHz, which has only three channels that don't overlap, a building can have dozens of networks competing for the same air. Your signal can be strong and still slow, because it keeps waiting its turn.

5 GHz helps twice over in an apartment. It has far more channels, and because it fades faster through walls, your neighbours' 5 GHz networks reach you much weaker than their 2.4 GHz ones. The distances inside a flat are usually short enough for 5 GHz to work in most rooms. If your router uses one name for both bands, it handles this itself; if a device keeps choosing 2.4 GHz near the router, see 2.4 or 5 GHz.

AirPort Utility's Wi-Fi scanner on an iPhone lists every network around you with its channel and signal, which is a quick way to see how crowded your building is.

Getting the router to the middle when you rent

You don't need to drill. Flat Ethernet cables are a few millimetres thick: they run along skirting boards with adhesive clips, under rugs, and under most interior doors or along the door frame. Fifteen or twenty metres cost very little and can be removed when you move out.

If your provider's box has to stay by the socket, connect your own router or an access point to it with the cable, put that in the middle, and turn off the Wi-Fi on the provider's box so devices don't stay connected to the one by the door.

When one router isn't enough

If a concrete wall cuts the flat in two and moving the router doesn't help, one extra unit on the far side usually solves it. It has to receive the router well, so with a mesh system it typically goes in the doorway or the corridor just before the wall, not deep inside the room behind it. With a cable it can go wherever you need it. Mesh or extender explains the options.