If you've recently moved into a new house and are having some difficulty getting a strong Wi-Fi signal, your house could be the culprit. Specifically the foil coating that might be residing under the exterior.
PCPro's Real World wireless expert, Paul Ockenden, states, "Modern homes constructed largely of plaster board also use signal-bouncing foil coating in bathrooms and kitchens".
A quick Google images search, for the product in question, returns some interesting images. You can see in the image above that the entire house has been wrapped in foil, not just the bathroom and kitchen. So with that in mind, what kind of Wi-Fi signal could these homeowners expect?
The foil coating discussed is Protect TF200 Thermo, a type of insulation. According to the site, "Protect TF200 Thermo is a high timber frame membrane with high tear strength, weather resistance and vapor permeability. Protect TF200 Thermo has all the features and benefits of the tried and tested TF200 membrane, but with the addition of a highly reflective surface enhancing the thermal performance of the final wall construction".
Sure, a "highly reflective surface" is great for home insulation, but it could be causing your Wi-Fi signal fits, as it will more than likely cause radio signals to just bounce around. Along with Wi-Fi, televisions, mobile phones, and even digital radios could be affected by the rouge signals.
Short of tearing down the your walls and removing the coating, there really isn't a lot that can be done if you suspect your signal is being bothered by your insulation.