so in my house (built 1955), a wall in the living room does not have a
grounded outlet and i need one there so i want to run an extension
cord/plug up from the basement. in the basement, above the drop
ceilings, there is a long piece of masking tape (ancient and unmarked)
that runs right about where i have roughly measured the wall on the
floor above it to be.

is it customary to mark the location of a wall of the floor above with
tape?

thanks everyone.