WAC 296-150V-0950
What requirements apply to roof coverings? (1) The roof covering must be securely fastened in an approved
manner to the supporting roof construction and must provide weather
protection for the vendor unit and the occupants.
(2) Exterior covering materials, including metal coverings,
must be moisture and weather resistant and contain corrosion
resistant fasteners to prevent wind and rain deterioration.
Note:
Electro-plated, electro-deposited zinc, and electro-galvanized staples are not considered corrosion-resistant materials.
(3) All exterior openings or penetrations into the conversion
vendor unit or medical unit around piping, ducts, plenums, or vents
must be sealed with moisture-resistant material.