Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Due to various constraints, I can not easily relocate my wireless router, and it is currently situated such that there are three walls and two mirrors between the router and my bed, where I frequently lose my wireless signal. Are the mirrors blocking or reflecting the wireless signal, or is it the walls? And what can I do about it?

share|improve this question
I've seen a similar issue a while ago... Is it double-sided mirrors or single sided? – r0ca Aug 4 '10 at 21:01
Yes, everyone, there is a bathroom between the mirrors. – Ryan Thompson Aug 5 '10 at 4:05
Definitly, we need to send this to MYTHBUSTERS! – r0ca Aug 5 '10 at 12:51
Apart from amoured concrete mentioned below, there are other reasons to get a bad signal too: 1. another router sending on the same channel (if the other router uses channel 1, use 6) 2. water in pipes 3. bluetooth, microwave ovens, a phone using 2.4 GHz band. Try to move the router 1 meter left, right, up, down and check the signal. – ott-- Dec 26 '11 at 17:38
up vote 7 down vote accepted

A (fairly modern) mirror shouldn't block your signal.

If there are two mirrors between your bedroom and the router: is there a bathroom, too? If that's the case then i would suspect that the tiles on the bathroom walls are one of the factors leading to your signal loss.

Is the building you live in build from armored concrete (like it's usual in Germany, for example)? Then you'll have another big factor.

share|improve this answer
@Ryan: You said there's a bathroom between your bedroom and the router. I'm pretty sure that's the problem. Tiled and/or thick walls with pipes and maybe other metal in the way are most likely the problem. Setting up a repeater/signal booster in there is probably not a good idea (it's wet and steamy). But maybe somewhere else? Otherwise you should think about relocating your router, using a wire (if possible) or pushing the signal strength. – lajuette Aug 5 '10 at 13:01
There's a closet to the side of the bathroom that has a clear shot to both the router and the bedroom. I could conceivably set up a repeater there. – Ryan Thompson Aug 5 '10 at 16:22
But don't forget: A bathroom is a wet environment. Your repeater should be able to handle a long and steamy shower/bath without short-circuiting. – lajuette Aug 5 '10 at 20:51
Everything except a vacuum attenuates WIFI signals, even modern aluminum backed mirrors. – dbasnett Aug 10 '10 at 14:33

It's conceivable an older mirror could cause issues. The glass shouldn't matter at all, but if they are heavy backed (silver or lead) it could be a problem. You're more likely to experience signal interference from other wireless sources like additional routers, cordless phones, etc.

It could also be the walls, but it would depend on what is in the walls. If it is a wall with a ton of plumbing and wiring, it could effectively block a wifi signal.

share|improve this answer
Mirrors usually equal bathroom, and bathroom usually equals plumbing, making that part of your answer a little more likely. – Joel Coehoorn Aug 4 '10 at 23:04

In a new bath room, much of the plumbing is plastic (PVC or ABS). in an older building it would be copper and cast iron, which will block more of the signal. Bathrooms also tend to have more wiring then other rooms which could block more of the signal. If the walls are tiled, they not only have the tile, but usually have a heavier cement based backer board which will block more of the signal then regular dry wall. Also don't forget the tub. A large cast iron tub would definitely block part of the signal. A fiberglass one would not block as much.

Finally as for the mirror, the silver backing can be expected to block the signal. On older mirrors the coating was actually silver which is an excellent conductor, meaning it would block the signal. Newer mirrors use a thinner silver colored paint usually with at least some aluminum in mix. It will still block at least some of the signal, but not as much as the thicker silver.

In summary, a new bathroom will not block as much of the signal as an older one will.

share|improve this answer
Well, my apartment is fairly old, so this might be it. – Ryan Thompson Aug 10 '10 at 4:59

You could get a wifi signal booster and situate in one of the in-between rooms that gets some reception.

share|improve this answer

Almost? everything attenuates WIFI signals, aluminum backed mirrors included. Here is a list of some common materials


share|improve this answer

I can tell you for certain that mirrored walls in two adjacent rooms (with a hallway in between) in a 20 year old house absolutely stops all wifi signals dead. There is one mirrored door between the two parts of the house and when it is open, a small amount of signal survives a few feet into the hallway. Door closed: no signal past the door.

It took a few months to diagnose the issue and we are considering a repeater in the attic or perhaps even outside to go around the mirrored walls that transect the house.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .