On Sunday, October 14, 2018, 12:46:49 PM PDT, Karl <gmkarl@gmail.com>
   wrote:

   "My name is Karl Semich and I have a desire to make available to
   everyone highly secure shielded rooms / SCIFs, for privacy and
   security in this modern age."
   <snip>
   "I then plan to try to measure a variety of setups ranging from
   homemade aluminum foil & iron paint to soldered copper and welded or
   bolted stainless steel, to identify ways for everyday people to
   cheaply create shielded environments that are actually effective.  I
   would like to find a way people can use off-the-shelf supplies to make
   environments that are isolated from DC to light, if desired."
   Sounds like a fascinating project.  You should take a while do define
   your goal.  Do you want the room to be magnetically (static; DC?)
   shielded as well?  If so, look for iron sheet or foil to back your
   aluminum-foil walls, floor, and ceiling.  However, iron foil is very
   expensive, compared with household-grade aluminum foil.
   [1]https://www.amazon.com/10x100cm-Tablets-Sheet-0-05mm-Thickness/dp/B0
   7C8FMH6Z
   Sheet metal, even if it is thicker than foil, would probably be cheaper
   than this.
   You may also want to install a layer to absorb the radio waves emitted
   inside the room.  There are commercial materials to do that, some form
   of iron compounds, known as "ferrites".  Google 'ferrite powder' for
   some examples.  There is also 'ferrite paint'.
   Take a look at the episodes of Better Call Saul, for an attorney who
   thinks that he is somehow allergic to electricity.  He lit his room
   with gasoline lanterns.  Lighting a radio-sealed room could be done
   with thick fiber optics (think rods, maybe 0.1" thick, driven by white
   LEDs through the walls.  Or, drive the white LEDS using batteries,
   inside the room itself.  (If you are willing to accept the small static
   magnetic field of the DC current flowing; driving the LEDs using
   coaxial cables should greatly reduce even that effect.)
                 Jim Bell

References

   1. https://www.amazon.com/10x100cm-Tablets-Sheet-0-05mm-Thickness/dp/B07C8FMH6Z