appearance of the surface to show through. You may also use cement-based paints, rubber-based
coatings, and vinyl and alkyd paints on many types of masonry. You may apply almost all exterior
house paints to masonry; however, you must prepare the surface properly. Good results are obtained by
painting concrete porches and steps with a rubber-based coating or similar product. Roughening the
surface slightly with muriatic acid is recommended before painting concrete that is hard and glossy. All
concrete surfaces must be primed with an alkali-resistant primer.
b. Types of Exterior Coatings. Several of the most commonly used coatings for exterior
surfaces are listed below. Notice that some are applied on exterior and interior surfaces. New paints are
being developed each year, so you should read the latest literature and technical publications to keep
abreast of new developments.
(1) White alkyd, latex, and acrylic paint. Alkyd paint is a glossy enamel that is compounded
for use as a second or final coat on exterior wood or metal and on interior drywall or plaster. It offers
heavy-duty protection for these surfaces. Alkyd paint also comes in a flat finish. Flat-latex and satin-
gloss acrylic paints are formulated for most exterior building surfaces of wood, metal, and masonry.
Most latex paints may be thinned slightly with water for spray application. For success with these
paints, always use an alkyd or latex exterior primer. Some latex paints are self-priming if they are
painted over previously painted wood surfaces that are in good condition.
(2) Masonry white latex (acrylic) paint. This paint is intended for exterior body or final coats
on primed masonry surfaces (except floors). The paint, white or tinted, dries to a flat finish; so when a
glossy finish is desired, you must use exterior glossy paints. Paint adheres poorly to glazed surfaces, so
you must roughen such surfaces by acid-washing, sandblasting, or rubbing the glaze off with abrasive
stones. It is unnecessary to remove old coatings, organic compounds, or cement-water paints that are
firm. However, you must remove paint that is loose or flaking to ensure adhesion of the new paint.
Since moisture is detrimental to exterior masonry paint, surfaces must be thoroughly dry before primer,
body, and final coats are applied.
(3) Zinc-oxide oil or resin paint. A zinc-dust and zinc-oxide paint is manufactured to prime
zinc surfaces. You may also use the paint for body and final coats. There are several types of this zinc
primer. One type is an air-drying paint that has a linseed-oil vehicle. Another type, an enamel, has a
glycerol-phthalate vehicle that causes the paint to dry faster. This enamel can be baked dry if necessary.
Still another type, an enamel containing phenolic resin, is recommended for priming the inside surfaces
of steel water tanks because the primer is nonpoisonous. Before using zinc primer on new surfaces, you
must clean the surfaces with turpentine, mineral spirits, or another approved cleaner to ensure good
adherence of the primer coat.
(4) Olive-drab oil-based paint. This exterior paint is suitable for use on wood, metal, and
masonry that is exposed to the elements. It is a semigloss paint that has good color retention, and it is
used for body and final coats.
(5) International-orange oil-based paint. This paint consists of two different types of paint,
and it comes in two colors-chrome orange (color of a ripe tomato) and orange red. The most durable
type of international-orange paint is chrome-orange-pigmented, linseed-