Steel-frame house a Faraday cage?

In a Facebook group for new house builders, someone asked if we had a regret about some aspect of building a house. This was my reply (with edits):
I built with a steel frame and a Colorbond roof. I don’t know which is the cause (could be a combination of the two), but radio/phone reception inside is poor-to-nonexistent:
  • I have to place the phone on the window sill and use an earpiece to hold a conversation. I am with Vodafone, whose signals are never as good as Telstra’s. I like its features and price, so I have not gone to Telstra.
  • The DAB2+ digital clock radio in the bedroom mostly works, but sometimes the alarm comes on with no radio signal.
  • I am also a ham operator and almost all VHF/UHF reception indoors is nonexistent.
  • I tried some rabbit-ears antenna on a TV set and there was no reception on any channel.
  • My wi-fi router is in the garage and although I don’t need it much in my home office at the far end, thanks to an Ethernet run, it is 2 out of 3 bars on the strength icon. If I step into my back yard, I lose the wi-fi on my phone completely.
The house is a Faraday cage.
Steel framing waiting to be erected.
Steel framing waiting to be erected.
The other issue is as the house heats up with the sun, there are ongoing pops in the roof space. My son has a similar home opposite mine from the same builder and he does not have this issue. A combination of a steel roof and steel framing should be avoided if you need good radio/TV/phone reception.