Also I wonder if lead paint actually attenuates signals. Prior to the bans in the late 70s was it known to interfere with TV or radio reception? I grew up in a farm house built in the 1920s and it had lead paint on some interior rooms as well as the exterior. Wifi and cell phones work fine there. I wonder if there is any actual data showing the signal attenuation levels caused by lead paint.

Working installing wifi commercially I got a pretty good idea of what would block wireless signals. Sheet metal, anything with a lot of water (trees, vegetation), and the ground were big culprits. It doesn't pass the sniff test for me that a sub mm thick layer of paint containing 0.5% lead would cause any significant signal loss. Maybe it's possible but I'm a "don't trust, verify" kind of person, especially when something goes against my real world experience.