Know your paints and primers

With paint and primer in one, also called direct to substrate (DTS) paints, two coats perform as well if not better than a primer coat and two topcoats of a typical paint.

With so many choices in paints and primers, it’s important to know the formulations and what that means in regard to performance to ensure a durable and attractive paint job. Jobsite conditions will dictate to a certain extent which paint and primer products you’ll use. The type of substrate (bare wood, unfinished drywall, concrete, metal), the condition of the substrate (stains, damage, previous layers of paint), and how the area will be used (requires repeated cleaning and/or exposed to frequent direct sunlight, water or humidity) all factor in to which paints and primers will do the best job.

Behr Premium Plus self-priming zero-VOC paint seals uncoated and previously painted surfaces without the need for a separate primer. The interior paint offers exceptional hide and a mildew-resistant finish, with faster drying times than previous low-VOC formulas.

Composition of paints and primers

All paints and primers are made up of three basic components: pigment to add color; solvents (water or oil) to make the product fluid enough to spread or spray; and binders, which hold the product together and with the pigment create a hard film once the solvent evaporates and the product dries. You often hear about “solids” in paint products, which refers to pigment, binders and any other additives that do not dry or evaporate after application.

Oil-based paints consist of pigment and resins in a solvent thinner, often mineral spirits. When the thinner evaporates, the resins form a hard coating with the pigment. Water-based paints simply use water as the carrier instead of solvent.

In the past, oil-based paint or primer has been the preferred product for certain applications – such as painting interior trim or priming bare wood – because of its superior adhesion and stain-blocking properties. And while many contractors still prefer oil-based products for those applications, manufacturers have refined latex paint products to the point that you can use them for almost any application with confidence.

Glidden Gripper is a multi-purpose latex primer specifically formulated for maximum adhesion on glossy, uneven and other hard-to-stick surfaces. The quick drying and recoat primer is also low odor and low VOC.

Benefits of a water-based (acrylic, latex) formulation are:

• Better gloss and color retention
• Breathable – won’t trap moisture
• Quicker drying with less odor
• Low VOCs (volatile organic compounds)
• Nonflammable
• Easy soap and water cleanup
• Some products may even qualify for contractor insurance discounts, as there are no hazardous materials involved and respirators aren’t necessary.

Benefits of an oil-based (alkyd) formulation are:

• Better surface penetration
• Better adhesion, generally speaking
• Wear ability
• Better flow and leveling
• Smoother finish with fewer applicator marks.

Remember too, that water-based products can be applied over oil-based, but not the other way around. For example, many professionals like to use an oil-based primer on problem surfaces and then a latex paint on top of that to take advantage of the benefits of both product types. Putting oil-based products on top of latex can easily cause the finish to bubble, peel or otherwise fail.

Peel Stop from Zinsser is a clear, binding primer, interior and exterior sealer formulated to strengthen peeling and chalky surfaces and promote adhesion of old paint coatings.

Paints

When choosing paint, always opt for quality over price. Top-quality paints reduce application time, cover better and provide much better results than lower-quality “bargain” paints. Some typical quality indicators for paints are:

• Higher volume of solids (binder, pigment). Read the label and look for 30 percent to 45 percent solids by volume.
• In latex paint, look for 100 percent acrylic binders.
• In oil-based paint, look for linseed (or soya) or modified (alkyd) drying oils.

When deciding what paint sheen to specify, keep the following in mind:

• Flat or eggshell – least amount of sheen, best at hiding minor surface imperfections, most popular choice for most interior wall surfaces.
• Semi-gloss or satin – commonly used in rooms requiring frequent cleaning (kitchens, baths, high-traffic areas) because of its stain resistance and easier cleaning.
• Gloss – better stain resistance than the others but highlights surface imperfections. Most popular on trim, cabinetry and doors, but not preferred for large surfaces such as walls.

Kilz Max primer is a water-based primer,
sealer and stain blocker formulated to
perform like oil- and shellac-based primers.

Primers

Primers seal a substrate, provide optimum adhesion to the substrate and provide a compatible surface for the topcoat to stick to. Except for color, there are almost as many choices in primers as there are in paints. A general-purpose primer will work well for most applications, but some substrates and conditions require specialized formulas. When choosing primers consider the following:

Does the job require stain blocking or stain killing? If so, what type of stain is it? Water stains, smoke damage and knots in bare wood are a few examples of stains that may require specific formulations. These are clearly marked on the label.

Shellac-based primers are generally recognized as the only reliable knot sealer and the most reliable stain and odor blocker.

Cracked and peeling paint, chalky surfaces, glossy surfaces (such as metal, glass or surfaces previously finished with polyurethane) will require primer specially formulated for those surfaces or problems.

Other problem surfaces, such as damaged drywall with peeling paper, have their own requirements as well.

More vibrant paint colors may require a gray primer or one tinted with a small amount of the topcoat color to improve coverage.

Paints and primers in one

Glidden Duo Paint + Primer combines the strong adhesion and hiding properties of a primer with a quality topcoat to provide a professional, durable finish.

DTS paints combine the best properties of the primer (adhesion and stain blocking) with that of the topcoat (durability and appearance) in a single product.

There are many choices of paints and primers in one for interior and exterior use. Two examples are Glidden Duo and Behr Premium Plus. Both are 100 percent acrylic paints available in hundreds of colors. The formulations clean up with soap and water, yet provide a denser, harder and more durable paint film when dry. Other benefits to these types of paints are the mildew-resistant finishes and reduced VOC (volatile organic compound) content, which, with Behr Premium Plus, is zero.

The Rohm and Haas Paint Quality Institute, an independent association that provides research and education on painting and paint products says DTS paints provide durability on both interior and exterior applications and bring real value to contractors. The institute forecasts the use of DTS products will be a growing trend in the market.