Still, an important factor in paint selection -- aside from personal color preference -- is gloss. Regardless of the type of coating you choose, the gloss of the one you buy will affect both its appearance and its durability. High-gloss paints are the most durable because they contain more resin than either semigloss or flat paints. Resin is an ingredient that hardens as the paint dries. The more resin, the harder the surface.
Consequently, for kitchens, bathrooms, utility rooms, doors, windows, and trim, high-gloss paints are ideal. Semigloss paints, with less resin and a reduced surface shine, are slightly less wear-resistant but still suitable for most woodwork. Finally, flat paints are the coatings of choice for most interior walls and ceilings because they provide an attractive, low-glare finish for surfaces that take little abuse and require only infrequent washings. Here's a paint primer to help you decide what kind of paint you need for the quick fix at hand.
The word "latex" originally referred to the use of rubber in one form or another as the resin, or solid, in paint. The solvent or thinner, called the "vehicle," was water. Today, many paints are made with water as the thinner but with resins that are not latex, and the industry is leaning toward such terms as "water-thinned" or "water-reducible." If the paints are called latex at all, the term often used is "acrylic latex" because they contain a plastic resin made of acrylics or polyvinyls rather than rubber.
In addition to the speed of drying, new opacity (the ability to completely cover one color with another), and washability of acrylic latex paints, the greatest advantage of water-thinned paints is you can clean up with water. The higher expense -- as well as the potential fire hazard -- of volatile thinners and brush cleaners is gone. If you wash the brush or roller immediately after the painting session is over, it comes clean in just a few minutes.
Latex paint works well on surfaces previously painted with latex or flat oilbase paints. It can even be used on unprimed drywall or unpainted masonry. However, latex usually does not adhere well to high-gloss finishes and, even though it can be used on wallpaper, there is a risk that the water in the paint may cause the paper to peel away from the wall. Because of its water content, latex will cause bare steel to rust and will raise the grain on raw wood.
Alkyd Resin Paint
The use of synthetic alkyd resin for solvent-thinned (oilbase) paints has brought several advantages. One of the most useful is a special formula that makes the paint yogurt-thick. A brush dipped in it carries more paint to the surface than previous versions. Yet, under the friction of application, the paint spreads and smooths readily.
In most gloss and semigloss (or satin) paints, alkyd materials are still preferred for trim, doors, and even heavy-traffic hallways. Many homeowners still like them best for bathrooms and kitchens, where they feel more confident of washability despite the availability of water-thinned enamels in satin or gloss that can be safely cleaned with standard household cleaners.
The opacity of alkyd paints has improved with the addition of a material that diffuses and evaporates, which leaves minute bubbles that reflect and scatter light and makes the paint look thicker than it really is. With paints of this formula, one coat of white will completely cover black or bright yellow.
While alkyds should not be used on unprimed drywall (they can raise the nap of its paper coating) or unprimed masonry, they are suitable for raw wood and almost any previously painted or papered surface. The most durable of interior paints, alkyds are dry enough for a second coat within four to six hours. Solvents must be used for thinning and cleanup. Check the label to find which solvent is recommended by the manufacturer. And, while the solvents may be almost odorless, they're still toxic and flammable, so you should work in a well-ventilated room.
Available only in a limited number of colors and in flat or low-gloss finishes, this paint contains a liquefied rubber. It is expensive and has a potent aroma, but, because rubberbase paint is waterproof and durable, it's an excellent coating for concrete. It can be applied directly to unprimed masonry. When used on brick, rubberbase paint should be preceded by a sealing coat of clear varnish. Before putting it on new concrete, wash the concrete with a 10 percent solution of muriatic acid, rinse thoroughly, and let dry completely. (Wear goggles and gloves when working with muriatic acid, and work in a well-ventilated space.) Like alkyds, rubberbase paints require special solvents; check the label for specifications.
If you're after a finish that looks like stucco, or if you want an effective cover-up for flawed surfaces, textured-surface paint will do the job. Some varieties come premixed with sandlike particles suspended in the paint. Because of their grittiness, these paints are usually used on ceilings. With other varieties, you have to add the particles and stir thoroughly. Another form of textured paint has no granules. Thick and smooth, it's applied to the surface and then textured with special tools. Textured paints are available in either flat-finish latex or alkyd formulations. Latex versions are frequently used on bare drywall ceilings because they can be used without a primer and they help to camouflage the seams between sheets of drywall.
One of the problems with textured paint becomes evident when the time comes to paint over it. All those peaks and valleys created by the texturing actually increase the surface area of the wall. The rough surface will require 15 to 25 percent more paint the second time around.
Quite a bit more expensive than conventional alkyd paint, dripless paint is ideal for ceilings because it's so thick it won't run off a roller or brush. It will usually cover any surface in a single coat, but, because it's so dense, it won't go as far as its more spreadable relatives.
With additional pigment to improve their covering capabilities, true one-coats are otherwise just more expensive versions of ordinary latex or alkyd paints. For best results, reserve them for use on flawless, same-color surfaces that have been previously sealed. Tip: Not all paints advertised as "one-coat" really are. Read the warranty.
Designed for use on acoustic ceiling tile, this paint covers without impairing the tile's acoustic qualities. It can be applied with a roller, but a paint sprayer is more efficient and less likely to affect the sound-deadening properties of the tile.
Primers are inexpensive undercoatings that smooth out uneven surfaces, provide a barrier between porous surfaces and certain finishing coats, and allow you to use an otherwise incompatible paint on a bare or previously painted surface. For flat paint finishes, the primer can be a thinned-out version of the paint itself. But that's often more expensive than using a premixed primer, which contains less-expensive pigment, dries quickly, and provides a firm foundation or "tooth" for the final coat of paint. Latex primer has all the advantages of latex paint -- almost odor-free, quick drying, and easy to clean up -- and is the best undercoat for drywall, plaster, and concrete. Don't use it on bare wood, though, because the water in it may raise the grain. For raw wood, it's best to use an alkyd primer.
Exterior painting requires different types of coatings. We'll examine exterior paints in the next section, as well as another common home repair tool -- abrasives.