All signs, except those attached flat against the wall of a building, shall be constructed to withstand wind loads as follows:
(a) For solid signs, thirty pounds per square foot on one face of the sign.
(b) For skeleton signs, thirty-six pounds per square foot of the total face area of the letters and other sign surfaces, or ten pounds per square foot of the gross area of the sign as determined by the overall dimensions of the sign, whichever is greater.
(1952 Code § 43-4-9)