CHAPTER 8STRUCTURAL COATINGSAND PRESERVATIVESThe final stage of most construction projects is theapplication of protective coatings, or “painting.” Aswith all projects, you should follow the plans andspecifications for surface preparation and applicationof the finish coat. The specifications give all the infor-mation you need to complete the tasks. But, to have abetter understanding of structural coatings, you needto know their purposes, methods of surface prepara-tion, and application techniques.PURPOSES OF STRUCTURALCOATINGSLEARNING OBJECTIVE: Upon completingthis section, you should be able to state thepurposes of the different types of structuralcoatings and how each is employed.The protection of surfaces is the most importantconsideration in determining the maintenance costof structures. Structural coatings serve as protectiveshields between the base construction materials andelements that attack and deteriorate them. Regularlyprogrammed structural coatings offer long-range pro-tection, extending the useful life of a structure.PREVENTIVE MAINTENANCEThe primary purpose of a structural coating isprotection. This is provided initially with new con-struction and maintained by a sound and progressivepreventive maintenance program. Programmed paint-ing enforces inspection and scheduling. A viablepreventive maintenance program will help ensure thatminor problems are detected at an early stage—beforethey become major failures later. An added advantagederived from preventive maintenance is the detectionof faulty structural conditions or problems caused byleakage or moisture.Resistance to moisture from rain, snow, ice, andcondensation constitutes perhaps the greatest singleprotective characteristic of paint, the most commontype of structural coating. Moisture causes metal tocorrode and wood to swell, warp, or rot. Interiorwall finishes of buildings can be ruined by moistureentering through neglected exterior surfaces. Porousmasonry is attacked and destroyed by moisture. There-fore, paint films must be as impervious to moisture aspossible to provide a protective, water-proof film overthe surface to which they are applied. Paint also actsas a protective film against acids, alkalies, materialorganisms, and other damaging elements.SANITATION ANDCLEANLINESSPainting is an essential part of general main-tenance programs for hospitals, kitchens, mess halls,offices, warehouses, and living quarters. Paintcoatings provide smooth, nonabsorptive surfaces thatare easily washed and kept free of dirt and foodstuffs.Adhering foodstuffs harbor germs and cause disease.Coating rough or porous areas seals out dust andgrease that would otherwise be difficult to remove.Odorless paints are used in these areas becauseconventional paint solvent odors are obnoxious topersonnel. In food preparation areas, the odors maybepicked up by nearby food.FIRE RETARDANCECertain types of structural coatings delay thespread of fire and assist in confining a fire to its areaof origin. Fire-retardant coatings should not beconsidered substitutes for conventional paints. Theuse of fire-retardant coatings is restricted to areas ofhighly combustible surfaces, and must be justified andgoverned by the specific agency’s criteria. Fire-retardant coatings are not used in buildings containingautomatic sprinkler systems.CAMOUFLAGECamouflage paints have special properties,making them different from conventional paints.Their uses are limited to special applications. Do notuse camouflage paints as substitutes for conventionalpaints. Use this paint only on exterior surfaces torender buildings and structures inconspicuous byblending them in with the surrounding environment.8-1
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