Best material for a faraday enclosure [closed]

I am having an issue with someone directly below me compromising my machines by tracking me with RF signals. I am looking for the most efficient way to set up a faraday enclosure to prevent this from continuing to happen.

Initially I looked into using faraday fabric that is composed primarily of nickel and copper. However the attenuation rating was only 80-100dB even if multiple layers of the fabric are used. Since the RF transceiver can be placed within a foot of the fabric layer on my floor I did not think that this attenuation rating was sufficient.

My next thought was to use multiple layers of aluminum foil as the protective layer, but I have no idea what level of protection that would provide without implementing it first. Can someone provide advice regarding if this the most effective approach or if I should construct it using different materials?