Almost every house has a room where the wi-fi does not work properly. The reasons are physical, and the fixes are more predictable than the marketing suggests.
What is actually blocking it
Wi-fi is radio, and radio is absorbed by material. In order of how badly they block a signal:
Water. Tanks, radiators, and the aquarium. Also people, which is why a busy room performs worse than an empty one.
Metal. Foil-backed plasterboard is the common one in modern houses and it is close to a complete barrier. Also metal studwork, mirrors, and metallised window coatings.
Solid masonry. Particularly older houses with thick brick or stone, and especially chimney breasts.
Underfloor heating. The metal mesh in the screed blocks signal between floors effectively.
This is why a router in the hall may serve the lounge perfectly and fail entirely in a bedroom the same distance away — the difference is what is in between.
Free things to try first
Move the router
The single most effective change, and it costs nothing.
Routers get installed where the phone line enters the house, which is usually by the front door, often in a cupboard, sometimes on the floor. That is the worst position available.
Wi-fi radiates outward and downward. Central, high, in the open. Moving a router from a hallway cupboard to a shelf in the middle of the house transforms coverage in most properties.
If the line entry position is the constraint, a longer cable from the socket to a better position is a cheap fix. This is easier than most people assume.
Get it away from other electronics
Televisions, microwaves, cordless phone base stations, baby monitors and speakers all interfere. A router behind a television is compromised.
Use the 5GHz band for what is close
Most routers broadcast two bands. 5GHz is faster with less interference but shorter range. 2.4GHz travels further and is more congested.
Devices near the router should use 5GHz. Devices at the far end of the house may need 2.4GHz. Many routers present both under one name and choose automatically, which works reasonably well.
Check the channel
In a terrace or a block of flats, your neighbours' wi-fi is your main source of interference. A phone app can show which channels are congested; choosing a quieter one sometimes helps considerably.
Move the router before buying anything. It is free, it takes ten minutes, and it fixes more houses than any product does.
When you need equipment
Extenders: the cheap option with a cost
An extender receives the signal and retransmits it. Because it does both on the same radio, throughput is roughly halved.
They also need to be placed where the existing signal is still good, which people rarely do — an extender in the dead spot has nothing good to extend.
Worth trying for a small area where you need coverage rather than speed. Not the answer for a whole house.
Mesh systems: the usual right answer
Two or three units that work together as one network, handing devices between them as you move.
Better than extenders because they are designed for it, and because devices switch between units properly rather than clinging to the first one. Setup is generally straightforward.
The important detail: a mesh unit connected back to the main unit by network cable performs far better than one connected wirelessly. Most mesh systems support this and most people do not do it.
Wired access points: the proper fix
A network cable from the router to an access point in the poorly served part of the house.
This is the best answer by a clear margin, because the connection back is not competing for radio time. If you can run a cable — during other work, through an existing route, along a skirting — it is worth doing.
Powerline adapters, which send data over mains wiring, are a partial alternative. Performance varies enormously with the state and layout of the wiring, and they will not cross between different circuits or consumer units.
What is not a wi-fi problem
Before spending anything, check whether the connection itself is the constraint. If speeds are poor everywhere including plugged in directly to the router, the problem is your broadband service — see broadband speed troubleshooting.
Also worth checking: whether one device is poor while others are fine in the same place, which points at that device rather than the network.
While you are at it
Change the router's administrative password if it is still the printed default. Use WPA3 or WPA2 with a strong passphrase. Turn off WPS, which is a known weakness. And set up the guest network for visitors so their devices are separated from yours — see home network security basics.
Our support team works with households across Suffolk and Norfolk on home networks, including properties where the signal has never reached the far end. Get in touch if you would rather it was sorted properly once.
