Loxon paint, technically recognized as a specialized line of coatings from Sherwin-Williams, is engineered specifically for the protection and aesthetic enhancement of exterior masonry and concrete surfaces. It is designed to withstand high-pH environments, resist alkali attack, and provide robust resistance against wind-driven rain, mildew, and efflorescence, making it a critical choice for commercial and residential exterior projects.
Understanding the Loxon Product Family
The term "Loxon" refers to a comprehensive suite of products within the Sherwin-Williams professional catalog, rather than a single paint product. Understanding the distinctions between these formulations is essential for achieving professional-grade results. The primary function of the Loxon line is to address the unique challenges of masonry, which include porosity, alkalinity, and moisture migration.
Unlike standard acrylic exterior paints, Loxon products are chemically formulated to be "alkali-resistant." When concrete or stucco cures, it produces lime, which raises the pH of the surface. Standard paints applied to "hot" (high-pH) masonry can suffer from saponification, where the binder in the paint reacts with the lime, leading to premature chalking, peeling, or total coating failure. Loxon coatings are designed to be applied to masonry with a pH as high as 13, eliminating the traditional requirement to wait 28 days for full concrete curing.
Key Product Classifications
The Loxon brand encompasses several distinct types of coatings, each serving a specific phase of the masonry restoration or finishing process:
1. Conditioners and Primers
Loxon Concrete & Masonry Primer is often used to seal porous surfaces. It acts as a bridge between the masonry substrate and the topcoat, creating a uniform surface that ensures even sheen and color development. This is particularly vital for porous materials like split-faced block or aged, chalky stucco.
2. Masonry Coatings and Sealers
Loxon Self-Priming Masonry Coating is a high-build formulation. It serves a dual purpose: it acts as both the primer and the topcoat. Its high-build nature allows it to fill small cracks and imperfections in the substrate, providing a monolithic, waterproof barrier.
3. Water Repellents
For projects where the natural look of the masonry must be preserved, there are clear, penetrating water repellents under the Loxon brand. These silane/siloxane-based sealers penetrate the pores of the concrete to provide hydrophobic protection without altering the appearance of the stone or block.
Technical Specifications and Prerequisites
Before beginning any project involving Loxon coatings, you must verify the condition of the substrate. While Loxon products are forgiving regarding pH, they are not a substitute for proper surface preparation.
Surface Cleanliness
The substrate must be free of oil, grease, wax, and loose particulates. If the masonry is old or has been exposed to the elements, power washing is usually required. For new masonry, you must remove "form release agents," which are chemicals used in the construction industry to prevent concrete from sticking to molds; these can prevent the paint from adhering properly.
Moisture Testing
Even though Loxon is resistant to alkalinity, it is not immune to hydrostatic pressure. If water is pushing through the wall from the interior—known as "negative side water pressure"—most coatings will eventually blister. Ensure the wall is dry enough for application. While many Loxon products can be applied to "green" (freshly poured) concrete, they should not be applied to surfaces that are actively saturated with liquid water.
Temperature and Weather Constraints
As of 2026, the application guidelines for Loxon remain consistent with industry standards for professional masonry coatings:
- Air and Surface Temperature: Do not apply if the temperature is below 35°F (2°C) or is expected to drop below 35°F within 48 hours of application.
- Humidity: High humidity can significantly extend the drying and curing time.
- Wind: Avoid application during high-wind conditions, as this can cause the coating to dry too rapidly, leading to "flash drying" and reduced film integrity.
Comparison of Loxon Masonry Solutions
| Product Type | Primary Function | Ideal Substrate | Key Advantage |
|---|---|---|---|
| Loxon Primer | Adhesion/Sealing | Porous Concrete/Stucco | Superior alkali resistance |
| Loxon Self-Priming Coating | Protection/Finish | CMU, Poured Concrete | High-build, fills small voids |
| Loxon Water Repellent | Hydrophobic barrier | Brick, Stone, Exposed Aggregate | Invisible, keeps water out |
| Loxon Vertical Concrete Stain | Aesthetic/Protection | Poured Concrete | Uniform color, matte finish |
The Application Process: Step-by-Step
Achieving a professional finish requires more than simply applying the product; it requires a systematic approach to the building envelope.
Phase 1: Preparation
Begin by inspecting the joints and masonry units. If there are cracks wider than 1/16 inch, these must be filled with a high-quality, paintable elastomeric sealant. Ensure all patching materials have cured according to the manufacturer's instructions before applying Loxon. If the surface is dusty, a quick rinse or air-blast is necessary to ensure the primer can bond to the substrate rather than a layer of loose dust.
Phase 2: Application Methods
Loxon coatings are typically high-viscosity products. For large commercial surfaces, airless spray application is the industry standard.
- Airless Spray: Use a tip size between .019 and .025. This ensures the high-solids content of the paint is delivered to the surface efficiently.
- Back-rolling: If spraying, it is highly recommended to "back-roll" the coating. This forces the paint into the pores of the masonry, ensuring the entire surface is encapsulated and that no pinholes remain.
- Brush/Roller: For smaller areas or architectural details, high-quality synthetic brushes or 3/4-inch to 1-inch nap rollers are preferred to hold enough paint for masonry textures.
Phase 3: Monitoring Curing
Loxon coatings typically dry to the touch in one to two hours, but they require significantly longer to reach full chemical cure. During this period, avoid contact with heavy cleaning equipment or abrasive materials that could compromise the integrity of the film.
Common Mistakes to Avoid
Many failures in masonry coating projects are attributed to poor application techniques rather than the paint itself.
- Over-thinning: While some thinning is allowed, exceeding the manufacturer's recommendations will reduce the film build, ultimately leading to poor water resistance and uneven color.
- Applying in Direct Sunlight: If the masonry is too hot, the water in the paint will evaporate instantly. This prevents the polymers from properly coalescing, leading to a weak, chalky, or peeling finish.
- Ignoring Pinholes: Concrete masonry units (CMU) are inherently porous. If you apply a single thin coat, you will likely leave thousands of "pinholes" that allow moisture to penetrate, defeating the purpose of the coating. Always ensure the "film build" matches the thickness requirements stated on the technical data sheet.
Troubleshooting Performance Issues
If you encounter issues such as peeling or cracking, the cause is almost always rooted in the state of the substrate rather than a manufacturing defect in the Loxon coating.
- Efflorescence: If white, powdery salt deposits appear on top of your fresh paint, it means the moisture was trapped inside the masonry. The paint has pushed the salts to the surface. You must address the moisture source—often a leaking gutter, a gap in window flashing, or improper landscape grading—before repainting.
- Blistering: This is often a sign of trapped moisture or application over a contaminated surface (like oil or form release agents). If this occurs, the failed section must be scraped away, the area cleaned, and the source of moisture mitigated before touch-up.
Frequently Asked Questions
Can I apply Loxon paint to non-masonry surfaces?
Loxon is specifically formulated for high-alkaline masonry surfaces. While it may stick to wood or metal, it is not engineered for these materials. Using it on surfaces it was not designed for may lead to poor adhesion or chemical incompatibility with the substrate.
Is Loxon paint considered an "elastomeric" coating?
Some products in the Loxon line, such as the Loxon XP Waterproofing System, are elastomeric. Elastomeric coatings are designed to be thicker and more flexible than standard paint, allowing them to "bridge" small cracks that may open and close due to thermal expansion. Always check the specific product label to confirm if you are using an elastomeric grade.
How long does Loxon paint last?
Longevity depends on environmental exposure, the quality of surface preparation, and the number of coats applied. In professional applications, when properly prepared and applied at the recommended dry film thickness, high-quality masonry coatings can provide protection for 10 to 15 years.
Can I use Loxon on interior basement walls?
Loxon products are designed primarily for exterior environments where UV resistance and breathability are required. For interior basement walls, particularly those prone to dampness, specialized basement waterproofing paints (often referred to as masonry sealers) are typically more appropriate as they are formulated to handle high hydrostatic pressure from the outside.
Does the paint require a topcoat?
This depends on the specific Loxon product. The Loxon Self-Priming Masonry Coating is designed as a standalone product. However, if you are using a dedicated primer, you must apply a high-quality exterior topcoat over it. Always refer to the technical data sheet for your specific product version to confirm the system requirements.
Professional Recommendation
For the best results, treat your masonry project as an engineering task rather than a decorative one. Always begin by conducting a moisture test and checking the compatibility of your existing substrate. If you are coating CMU or stucco, prioritize the Loxon XP or similar high-build formulations to ensure you are filling the pores adequately. When in doubt, consult the official Sherwin-Williams technical data sheets, as they contain the exact mil-thickness requirements for your specific project climate and surface type. By treating the substrate with the respect its chemical properties demand, you ensure the longevity of your exterior finish for years to come.
