What's killing your Wi-Fi? Wrapping your house in tin foil

14 Apr 2011

On the cover of this month’s magazine (on sale today) we ask: what’s killing your Wi-Fi? Among the many answers – and solutions – you’ll find in our cover feature is one supplied by our Real World wireless expert, Paul Ockenden.

“Modern homes constructed largely of plaster board also use signal-bouncing foil coating in bathrooms and kitchens,” Paul offers as one possible reason for erratic Wi-Fi reception.

Judging by a walk past a local housing development, it’s not only kitchens and bathrooms that are being turned into giant Faraday cages – it’s the whole house.

The picture above shows a new-build property being wrapped, from floorboards to rafters, in a material called Protect TF200 Thermo. A quick Google search for the material in question uncovers a detailed PDF explaining its many benefits, including “enhanced thermal protection” and “high tear strength”. What it doesn’t explain is the effect this material will have on radio signals such as Wi-Fi, mobile phone, or even digital radio and television reception. I sent an email to the company’s technical department two days ago, but have yet to receive a reply.

There’s one line in that PDF that should set alarm bells ringing however: “Protect TF200 Thermo provides a highly reflective yet permeable low emissivity layer.” I wouldn’t mind betting that highly reflective layer might well bounce your radio signals in an unpredictable fashion.

If owners of these brand-spanking new houses move in and discover they can’t get a reliable Wi-Fi signal in the garden, or that they can't get a reliable 3G signal on their smartphone, that foil-like coating might well be the culprit. Conversely, it might even improve Wi-Fi signals internally by mirroring the signal.

The real issue is the new homeowners probably won’t know what’s causing their Wi-Fi woes. Unless they’ve looked at the plans in fine detail, or happened to pass by while the house was being constructed, that foil wraparound will be obscured from view by their exterior wall. Modern insulation regulations are all well and good, but is anyone even considering the effect this stuff has on radio reception?

So if you’ve moved into a modern home and are wondering what’s killing your Wi-Fi, the answer might well be the house itself. And short of tearing the walls down and starting again, there’s probably not a lot you can do about it.

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