Duraguard Protective Coating Solutions
Commercial & Industrial Concrete Floor Systems & polishing
Durapoxy 520 — Moisture-Tolerant Penetrating Epoxy Primer & Sealer
The Universal Primer for Wet, Damp, and Moisture-Affected Concrete Slabs
Not every concrete slab is dry. Basements, below-grade floors, slabs on ground, and older industrial floors frequently carry moisture that makes standard epoxy primers impractical or impossible to apply. Durapoxy 520 solves that problem. Duraguard’s water-based, moisture-tolerant penetrating epoxy primer and sealer is engineered to bond to damp and moisture-affected concrete where solvent-based primers cannot — delivering the same deep penetration, outgassing prevention, and substrate sealing that every high-performance floor system requires, regardless of slab moisture conditions. Installed by Duraguard Protective Coating Solutions throughout Wisconsin and Illinois since 1993, Durapoxy 520 is the universal first coat for facilities where moisture is a factor.
What Is a Moisture-Tolerant Epoxy Primer?
Standard epoxy primers require a dry substrate to bond properly. When moisture is present in the concrete — whether from hydrostatic pressure, a high water table, a below-grade slab, or simply a floor that was washed down and not fully dried — a solvent-based primer will not achieve proper adhesion. The moisture interferes with the chemical bond, leading to delamination, blistering, and premature coating failure.
A moisture-tolerant primer like Durapoxy 520 is formulated differently. Its water-based chemistry is compatible with damp concrete surfaces, allowing it to penetrate and bond even when the slab contains residual moisture. Rather than being repelled by moisture at the surface, Durapoxy 520 works with the concrete’s moisture content to achieve the penetration and adhesion needed as a primer and seal coat.
The result is a reliable foundation coat that performs on the full range of concrete conditions Duraguard encounters in real-world industrial and commercial installations — from perfectly dry slabs to moisture-affected floors that would cause a standard primer to fail.
Why Durapoxy 520?
Moisture Tolerant — Works Where Other Primers Cannot
Durapoxy 520’s water-based formulation allows it to bond to damp and moisture-affected concrete surfaces. For facilities with below-grade floors, slabs on ground, older industrial concrete, or floors in humid environments, Durapoxy 520 is the primer that makes the rest of the system possible. When moisture conditions rule out solvent-based primers, Durapoxy 520 is the right call.
Deep Penetration — Seals the Substrate
Like all effective epoxy primers, Durapoxy 520 penetrates into the concrete’s pore structure rather than sitting on top of the surface. This deep penetration fills voids, seals the substrate, and creates the mechanical lock between the primer and the slab that the entire floor system depends on. The result is a uniformly sealed surface that gives every finish coat above it the foundation it needs.
Prevents Outgassing — Eliminates Pinholes and Surface Defects
Outgassing — the release of trapped air from concrete pores upward through a curing topcoat — is a leading cause of pinholes, bubbles, and surface defects in epoxy floor installations. Durapoxy 520 seals the concrete pores completely before the finish coat is applied, stopping outgassing at the source and delivering a smooth, defect-free surface ready to receive any Duraguard finish system.
Universal Compatibility — Goes Under Every System
Durapoxy 520 is compatible with the full range of Duraguard coating systems. It can be applied under Durapoxy TC topcoats, under urethane concrete systems like Duraclad 903, under decorative flake and broadcast systems, and under any other Duraguard finish coat. When moisture conditions are a factor, Durapoxy 520 replaces TCX as the primer layer without changing anything about the finish system above it.
Water-Based — Low Odor for Occupied Facilities
Because Durapoxy 520 is water-based, it produces minimal odor during application and cure. This makes it practical for occupied facilities, food processing environments, and any space where solvent odor during installation is not acceptable. Combined with its moisture tolerance, this makes Durapoxy 520 the right primer for a wide range of real-world installation conditions.
8 to 12 Hour Cure
Durapoxy 520 cures in 8 to 12 hours under normal conditions, keeping multi-coat installation schedules on track and allowing finish coats to be applied the following shift or the next day.
Where Durapoxy 520 Is Used
Below-Grade and Slab-on-Ground Installations
Floors below grade or directly on ground are subject to moisture migration from the soil and water table. Standard primers fail in these conditions. Durapoxy 520’s moisture-tolerant formulation makes it the correct primer choice for any below-grade floor or slab-on-ground installation where moisture vapor transmission is a concern.
Older Industrial and Commercial Concrete
Older concrete slabs frequently carry more moisture and are more porous than newer construction. Durapoxy 520 penetrates and seals these substrates effectively, giving aged industrial floors the same quality primer foundation as new construction.
Food and Beverage Processing Facilities
Food processing facilities that wash down floors regularly create conditions where residual moisture in the slab is common. Durapoxy 520’s moisture tolerance and low odor make it the right primer for food processing installations where both moisture and occupied-facility requirements must be met.
Manufacturing and Warehouse Floors
Industrial manufacturing and warehouse floors in older buildings, facilities near water, or environments with high ambient humidity benefit from Durapoxy 520’s ability to bond and seal in conditions where standard epoxy primers are unreliable.
Any Installation Where Moisture Is a Factor
Whenever a site assessment identifies moisture in the concrete slab — whether measured by calcium chloride test, relative humidity probe, or visual inspection — Durapoxy 520 is the primer that gives the finish system the best chance of performing to its full design life. Skipping moisture-tolerant priming on a damp slab is the most reliable way to get a coating failure.
Durapoxy 520 vs. Durapoxy TCX — Choosing the Right Primer
Both Durapoxy 520 and Durapoxy TCX are high-performance epoxy primers engineered to seal concrete and prepare the substrate for Duraguard’s finish systems. The difference is moisture tolerance.
Durapoxy TCX is a 94% solids solvent-based primer best suited for dry concrete substrates where maximum film build and penetration are the priority. Durapoxy 520 is the water-based, moisture-tolerant alternative for slabs where residual moisture makes a solvent-based primer impractical.
Duraguard evaluates substrate moisture conditions during every pre-installation site assessment and specifies the correct primer for the conditions present. In many cases, the choice between TCX and 520 is determined by a simple moisture test — not by preference or cost.
The Duraguard Installation Process
Proper surface preparation is critical regardless of which primer is specified. Duraguard prepares concrete by diamond grinding or shot blasting to open the surface profile and remove any existing coatings, oils, or contaminants before Durapoxy 520 is applied.
Moisture testing is performed as part of every pre-installation assessment to identify slab conditions and specify the correct primer. When Durapoxy 520 is indicated, our installation crews apply it at the correct coverage rate and film thickness to ensure complete substrate sealing before the finish system is applied.
We work around your production schedule, including nights and weekends, to minimize downtime during installation.
Service Area
Duraguard installs Durapoxy 520 moisture-tolerant primer and seal coat systems throughout southeastern Wisconsin and northern Illinois including Racine, Kenosha, Milwaukee, Waukesha, Waukegan, Gurnee, Libertyville, and surrounding areas.
Get a Free Floor Assessment
If your facility has moisture concerns, an older slab, or a below-grade floor — or if your current coating is failing and you suspect moisture is the cause — contact Duraguard today for a free on-site assessment. We will evaluate your slab conditions, identify moisture issues, and specify the right primer and system for your environment.
Call us at (833) 387-2482 or use our contact form to request your free evaluation.
Duraguard Protective Coating Solutions is proud to align with leading industry organizations that set the standard for flooring excellence and business integrity. We follow the guidelines and technical standards established by the International Concrete Repair Institute (ICRI), ensuring every project meets rigorous industry benchmarks. As an accredited member of the Better Business Bureau (BBB), we are committed to transparency, trust, and customer satisfaction. Duraguard is also recognized through Wisconsin Manufacturers & Commerce (WMC), reflecting our dedication to Wisconsin’s manufacturing and business community.