I did it inside my bedroom, ceiling and all walls because we are fairly close to a cell tower. The rf meter I have went from 3000-5000 down to 7-10. I can't type the symbols in my phone for the units. Better sleep for sure since doing that a couple of years ago.

Windows we used film, curtains shielded too. Two coats primer. Put copper stripts to ground as well on walls before paint. Didn't do floor so some rf gets in and out which is ok actually, you can create a focusing effect if you aren't careful about it.