Old plaster walls can block Wifi signals

If you’re cursing your lousy Wifi signal, it may just be because you’re sitting inside a Faraday cage.


It’s long been known that thick stone walls like those found in many old European houses can block cellphone and Wifi signals.

But it’s now emerged that houses built with metal chicken-wire in the plaster walls can block the signal generated by Wifi networks just as effectively.

Ironically, it’s a particular problem in the Silicon Valley area, where many old houses are built this way rather than with drywall, or plasterboard.

A Faraday cage is usually used to block electrical fields, but also works against electromagnetic radiation. Because the holes in chicken wire are smaller than the 2.4GHz Wifi signal wavelength, the wire has the same effect as solid metal.

The Wall Street Journal  spoke to San Francisco resident Galen Pewtherer, who tried everything imaginable to improve his signal – including rigging up a Pringles can as a signal-boosting antenna. It didn’t work.