6.8.2 In the event the required minimum thickness is not
achieved as specified, additional coats shall be applied in accordance
with the manufacturerʼs instructions until the required
thickness is obtained. The inorganic zinc-rich coatings shall
not be corrected in this manner unless the manufacturer's
instructions specifically permit this practice.
----quoted from sspc sp1
moreover,refer to SSPC-Guide 14 - Guide for the Repair of Imperfections in Galvanized or Inorganic Zinc Coated Steel Using Organic Zinc-Rich Coating