Why is my Wi-Fi so bad upstairs?

Broadband comes into the house where the old phone line did. In most London terraces that's the front hall, by the door, about a foot off the floor. The router goes wherever the cable stops, and then everybody wonders why the back bedroom upstairs gets one bar and the video calls freeze at half past seven.

It's the first thing listed on my home tech support page, and it's usually the cheapest job on there. Here's what I check, in the order I check it, and roughly what each fix costs. Most of it you can do yourself.

First: is it the Wi-Fi or the line?

Before touching anything, I take three speed tests: one on a laptop plugged into the router with a cable, one over Wi-Fi standing right next to the router, and one upstairs in the room that's actually the problem, at the time of day it's usually worst.

If the wired number is poor, the Wi-Fi isn't your problem and no amount of kit will fix it. That's a call to your provider, and I'll tell you what to ask them for. If the wired number is fine and the upstairs one falls off a cliff, it's the Wi-Fi. Ten minutes, and it stops people spending £200 on a mesh kit to fix a fault on the line.

Why upstairs is worst

A router sends its signal out in every direction, like a light bulb with no shade. Put it in a corner of the hall at skirting height and a good share goes into the street and the ground. Ofcom's advice, in its Wi-Fi guidance published in February 2024, is to put it centrally and off the floor, for exactly that reason.

Then there's the floor. Between the hall and the back bedroom you've got joists, plasterboard, sometimes foil-backed insulation, and usually a radiator or two on the way. Ofcom names walls, water, metal and glass as the things that weaken the signal. A fish tank in the front room is a surprisingly good Wi-Fi blocker. So is a big mirror.

The two bands make it worse. Most routers broadcast 2.4 GHz and 5 GHz under one network name and let each device pick. The 5 GHz band is quicker but it doesn't get through floors nearly as well, and phones are stubborn about letting go of it. So the phone upstairs clings to a weak 5 GHz signal when a slower, steadier 2.4 GHz one was available all along.

And it's November. Ofcom lists fairy lights alongside microwaves, baby monitors and cordless phones as things that interfere. I'm not telling anyone to skip the tree. But if the Wi-Fi gets worse every December, that's worth knowing.

The fixes, cheapest first

Move the router. Even a shelf a metre up helps. If it has aerials, point them different ways, one upright and one flat. If the socket really is in the worst place in the house, a longer cable from the socket to a better spot is often all it takes. That costs a few pounds. Your provider may also be able to move the socket, though that's usually a paid engineer visit.

Run a cable to the room that matters. If the thing upstairs is a desktop PC or a games console that never moves, a cable beats any Wi-Fi. Ofcom says as much. In a terrace it means a hole through a floor and some clips along a skirting board, which not everybody wants. When it's possible, it's the fix I'd pick every time.

Powerline adapters. These send the connection through your electrical wiring: one plugs in by the router, the other upstairs. Ofcom puts them from around £20. They're a gamble on your house, because on one circuit they can be excellent while across two circuits, or behind an old consumer unit, they can be next to useless, and there's no way of knowing which you've got until you plug them in and try. Buy them somewhere that takes returns.

A mesh kit. Two or three boxes that pass the signal between them and show up as one network. Ofcom quotes starter packs at about £60 to over £200. In a bigger house, or one with solid walls, mesh is often the right answer. It's also where I find the most half-working setups. Three mistakes come up again and again:

• The second box goes in the room with no signal. It needs a decent signal to pass on, so it belongs halfway, on the landing or the top of the stairs, not in the dead room itself.
• The provider's router keeps broadcasting its own Wi-Fi alongside the mesh. Now the house has two networks with different names, and devices hop between them.
• A cheap plug-in extender from years ago is still in a socket somewhere, adding a third.

The best mesh setup has a cable between the boxes rather than relaying over the air. Which brings you back to the second fix.

A newer router. If yours is old or drops out on its own, a newer one usually copes with more devices. Ring your provider before you buy one, because they sometimes send a newer model for nothing, especially if you're near the end of a contract and they'd like you to stay. A router you buy yourself can be better, but if something goes wrong the provider's support line may not help with it.

What I do when I come out

In London I come to the house. Elsewhere I can usually do the first half remotely. The visit is the three speed tests, a walk round every room with a phone measuring the signal, and a look at the router's own settings. Then I tell you what I'd do and what it will cost before anything gets bought. There's no price list, because a flat where the router just needs moving and a four-floor house with solid walls aren't the same job.

Sometimes the answer is moving a box two metres, and you've paid me to say that. I'd rather say it than sell you a mesh kit you didn't need. If the fault is the provider's, I'll say so. Then I stop.

Common questions

Will a Wi-Fi extender fix it?
Sometimes, and it's the cheapest thing to try. Most extenders repeat the signal over the air, so the speed through them is lower than the router's, and many create a second network name. Fine for a phone in a back bedroom. Not great for a work laptop on video calls all day.

Should I switch off 2.4 GHz?
Usually not. Older devices, smart plugs and anything far from the router often need it. Giving the two bands separate names is sometimes better, so you can choose which one the PC upstairs uses.

Is mesh worth it in a flat?
In a one or two-bed flat, rarely as the first step. Move the router and check the line first. Mesh earns its money in bigger houses, extensions and anywhere with solid walls.

If you'd rather somebody just came and sorted it, that's what my home tech support is for: Wi-Fi and router problems, slow PCs and backups, in person in London. Tell me what's going wrong and I'll tell you what I'd do and what it costs before I start.