Applying the same exterior paint to brick, stucco, and wood siding is like using the same drill bit for steel, concrete, and wood. Each material has a fundamentally different relationship with moisture, alkalinity, movement, and surface texture. Using the wrong paint on a given substrate does not simply produce a suboptimal result. It produces a predictable failure: moisture locked behind an elastomeric coat on wood causes rot, an alkali-intolerant primer on freshly cured concrete fails within one season, and a rigid alkyd on stucco that micro-moves with temperature cracks along every stress line.

Understanding why each substrate is different, and matching the paint system to those properties, is the starting point for exterior work that holds up across multiple seasons.

Why Each Substrate Needs a Different Paint Approach

The three most common exterior siding materials each present a different primary challenge.

Brick is highly alkaline and extremely porous. Fresh brick and mortar have a pH of 12 to 13. Standard paint primers applied to high-alkalinity masonry fail as the alkaline compounds saponify the binder and cause the primer to delaminate. Beyond alkalinity, brick absorbs enormous volumes of paint due to its porosity. Coverage rates on rough brick run significantly lower than the flat-surface estimate on the can label. Any product applied to brick must tolerate both the alkalinity and the absorption without failing.

Stucco shares brick’s alkalinity and porosity but adds a third challenge: micro-movement. Stucco expands and contracts slightly with temperature and moisture cycling. It develops hairline cracks over time, and those cracks admit water unless the paint film is flexible enough to bridge them and move with the surface. A rigid film over stucco is a film that will crack.

Wood siding moves dramatically compared to masonry. Across the grain, wood expands and contracts 2 to 6 percent as moisture content changes with humidity and weather. End grain absorbs moisture two to three times faster than face grain. Wood also presents the tannin challenge: cedar and redwood contain extractives that bleed through water-based primers and discolor the topcoat. Any paint system for wood must accommodate movement and seal against moisture entry from all directions.

Best Exterior Paint for Brick Homes

Once-painted brick surfaces are committed. Paint seals the porous face of the brick and changing the approach later is expensive. Using the right product from the start matters enormously.

The Sherwin-Williams Loxon product line is specifically engineered for masonry surfaces. Loxon XP Masonry Coating is a direct-to-concrete and direct-to-masonry option that handles surface alkalinity up to pH 13 without primer. It provides approximately 80 square feet of coverage per gallon on rough stucco and similar masonry surfaces, compared to the 350 to 400 square feet a standard paint covers on smooth surfaces. Its VOC content is under 50 grams per liter.

For surfaces that need a primer before topcoating, the Sherwin-Williams Loxon Concrete and Masonry Primer/Sealer is the matched primer for the Loxon system. It tolerates fresh masonry alkalinity and should not be applied below 40 degrees Fahrenheit. New masonry surfaces must cure a minimum of seven days before any coating.

The Loxon Acrylic Coating topcoat, when applied at 8 mils wet and 3.7 mils dry, dries to touch in four hours and is ready for recoat after 24 hours.

For brick specifically, the question of vapor permeability is significant. Brick walls need to breathe. Moisture that enters a brick wall from inside or outside must be able to escape. A film-forming coating with very low vapor permeability traps moisture in the brick, which causes spalling, efflorescence, and freeze-thaw damage in cold climates. Choose masonry coatings with a perm rating that allows adequate vapor transmission for the wall assembly being coated.

Best Exterior Paint for Stucco Surfaces

Stucco’s combination of alkalinity, porosity, and movement makes elastomeric coatings the strongest choice for most stucco homes. An elastomeric coating stretches 150 to 400 percent, bridging hairline cracks as they develop with temperature cycling rather than cracking with them.

Sherwin-Williams Loxon XP Waterproofing Masonry Coating combines waterproofing and color in a single-product system designed for stucco and other masonry surfaces. For maximum crack-bridging performance, a dedicated elastomeric topcoat applied at full wet film thickness provides the best results.

When spraying elastomeric products, use an airless sprayer tip in the 0.019 to 0.023-inch range and a pump with a minimum capacity of 1 gallon per minute. Standard sprayer tips and smaller pumps cannot move the thick product adequately. After spraying, back-roll the surface immediately with a 3/4-inch nap roller to press the coating into the texture. This back-rolling step is not optional on stucco. Elastomeric sprayed without back-rolling sits on the high points of the texture rather than filling the valleys, leaving unprotected recesses that fail early.

The BEHR Masonry Bonding Primer (number 880) is an alternative primer option for stucco before a latex or elastomeric topcoat. Its water-thin viscosity allows it to penetrate into the surface rather than bridging over it. Apply the topcoat no sooner than four hours after the BEHR primer dries, and complete topcoating within 30 days of priming.

Best Exterior Paint for Wood Siding and Clapboard

The long-running debate between oil-based and water-based paint for wood siding has a clear answer for long-term performance: 100 percent acrylic latex. Oil-based alkyds offer better initial adhesion on bare wood and greater flexibility during the first few years. However, alkyds become brittle over time outdoors. As the oil component oxidizes, the film loses its ability to flex with the wood’s seasonal movement. Cracking and peeling follow.

One hundred percent acrylic latex stays flexible across multiple decades of freeze-thaw cycling and humidity changes. It also allows the wood to breathe more effectively than a rigid alkyd film, reducing moisture buildup at the paint-wood interface.

For primed bare wood, the primer selection is as important as the topcoat choice. On cedar and redwood, water-based primers used alone will allow tannin bleed, a brownish discoloration that bleeds through the primer and discolors any topcoat. The correct approach is to spot-prime knots and sap streaks with Zinsser BIN shellac-based primer first, then full-surface prime with an oil-based exterior primer such as Zinsser Cover Stain. This two-step primer system blocks tannins reliably.

Where local VOC regulations permit, oil-based exterior primers on bare wood provide superior penetration into open grain and excellent tannin blocking. In regulated states, Benjamin Moore Advance Waterborne Alkyd offers alkyd-level adhesion and leveling with water cleanup and VOC under 50 grams per liter.

Moisture content must be below 15 percent in wood siding before any primer is applied. Back-prime all six faces of boards before installation to block moisture vapor from entering through the back face.

Primer Requirements That Differ by Substrate Type

Masonry and wood require different primer chemistry, and using the wrong one is as problematic as skipping primer entirely.

For masonry and brick: Use an alkali-resistant masonry primer. Standard latex primers saponify on fresh concrete and mortar above pH 12. Masonry-specific primers are formulated to tolerate high alkalinity and bond reliably to the irregular, porous texture of concrete, brick, and stucco. Allow new masonry to cure a minimum of 28 to 30 days before priming in most cases, though Loxon products specify a shorter window of seven days.

For wood: The primer must seal against moisture entry through end grain and face grain, block tannin bleed on resinous species, and provide enough solids to fill open grain texture. Oil-based exterior wood primers do all three effectively. Acrylic exterior primers are acceptable on pre-primed or painted wood and on species without tannin issues but may require two coats on bare cedar or redwood.

For metal: Masonry and wood primers do not adhere to metal and do not prevent rust. Metal substrates require a rust-inhibiting primer with zinc phosphate or a rust-converter primer such as Corroseal before any topcoating.

How Surface Porosity Affects Paint Coverage and Longevity

Coverage rate is not a fixed number. It varies substantially with surface porosity, and ignoring this when estimating paint quantities leads to either running short of paint midway through a project or applying insufficient film thickness in an attempt to make paint stretch further.

A gallon of premium exterior latex covering 350 to 400 square feet on a smooth primed surface covers 150 to 200 square feet on rough-sawn wood or deeply textured stucco. Brick with open mortar joints may absorb even more per square foot on first application.

Insufficient film thickness is one of the most common causes of shortened paint life. The protective performance of any paint system depends on achieving the minimum dry film thickness the manufacturer specifies. On high-porosity surfaces, the first coat soaks in and provides almost no protective film. The second coat, applied over the sealed first coat, provides the actual protective layer. This means that on brick or stucco, two coats are a functional minimum and three coats provide meaningfully longer protection in high-UV or high-moisture environments.

On wood siding, using a filled primer that builds film thickness faster reduces the number of topcoats needed while still reaching the required total dry film thickness.