Janesville Epoxy Flooring coats basement floors with epoxy in Janesville, WI, serving surrounding cities including Milton, Edgerton, Beloit, South Beloit and Evansville. In more than 20 years of this work, the lesson we keep coming back to is simple: a basement floor coating succeeds or fails on moisture. That is why moisture testing is a line item in every basement scope we write, not something offered after a floor has already blistered.
A basement slab sits in the ground, surrounded by soil that holds water after every storm and every spring thaw. Some slabs stay dry enough to coat with a standard system, some need a moisture-mitigation primer, and a few should not be coated at all. We find out which one you have before we quote, because guessing wrong costs you the whole floor.
Our proposals name the primer, the base coat, the topcoat and the finished thickness, and we read the warranty exclusions aloud before you sign, with moisture named first. We never sell a coating as flood protection, as radon reduction or as a fix for water coming up through a slab. What we do sell is a durable, washable floor on a slab that has been tested and prepared to hold it.
Moisture Comes First in a Basement
How We Test a Basement Slab
Testing starts with a look at the floor and walls for staining, dampness and white deposits. From there we choose the right method for the slab: an ASTM D4263 plastic sheet test as a quick screen, an ASTM F1869 calcium chloride test to measure how much vapor the slab emits, or ASTM F2170 relative humidity probes set into drilled holes. Each tells us something different about what the concrete is doing.
We compare the readings against the coating manufacturer’s limits and the moisture thresholds referenced in ASTM F710. Those numbers decide whether the floor gets a standard 100% solids epoxy, a moisture-mitigation primer underneath, or an honest recommendation not to coat.
Hydrostatic Pressure Under the Slab
When groundwater rises after heavy rain or snowmelt, it presses up against the underside of the basement slab. That pressure can drive moisture through the concrete with enough force to lift a coating, even when the surface looks dry most of the year. It is the reason a floor that seems fine in August can fail in April.
We ask about the home’s water history, look at the sump and drainage, and test at more than one location where conditions vary. If pressure is significant, a coating alone is the wrong answer, and we will say that rather than install one.
Summer Condensation on a Cool Floor
In summer, warm humid air reaches the cool basement slab and condenses on it, leaving the floor damp even when no water is rising from below. Homeowners often mistake this for a leak, and coating over it traps moisture between the floor and the epoxy. Dehumidification usually solves it.
We measure the dew point spread at the slab surface before every coat. If the floor is too close to condensing, we run dehumidifiers and wait, because a coating applied to a sweating slab will not bond properly.
Reading a Basement Floor’s Warning Signs
Efflorescence and White Staining
Efflorescence is the white, chalky powder left when water carries dissolved minerals to the surface and evaporates. It tells us moisture is moving through the slab, even if the floor feels dry today. We never coat over it.
We grind efflorescence away completely so the coating bonds to clean concrete, and we use its location to decide where to place our moisture tests. Heavy, recurring deposits point toward a water problem that needs solving before any coating is considered.
Cracks, Old Paint and Previous Coatings
Many basements here were built in the 1960s and 1970s, and their slabs carry decades of paint, sealer and patchwork. Old floor paint is one of the most common reasons a new basement coating fails, because it blocks the bond to the concrete. We grind it off rather than coating over it.
Cracks are opened up and filled with a rigid repair material, then ground flush. Cracks that leak water or keep moving are flagged before we quote, since they may need a foundation or drainage fix first.
Sump Pits, Floor Drains and Edges
The sump pit, floor drains and the joint where the slab meets the walls are where water appears first and coatings tend to fail first. We detail those edges carefully, keep the sump and drains fully working, and never seal over anything that is meant to carry water away.
Where the floor slopes toward a drain, we keep that slope intact. A coated basement should still drain the way it was designed to if water ever does get in.
Coating a Basement After a Flood
Water From the Rock River and Spring Storms
The Rock River crested at a provisional 12.11 feet at the Afton gauge on April 18, 2026, the highest reading there since 2008 and well above the 9.0-foot flood stage. The storms of April 17 brought flash flooding in Janesville, with basements holding about a foot of water, and Rock County was included in the Wisconsin disaster declaration. Many local basement floors took water that spring.
If yours did, the slab needs to dry before anything else happens. Concrete that has soaked for days can take weeks to release that moisture, even after the visible water is gone.
Drying, Retesting and Then Coating
After a flood, we start with testing, not with a schedule. We take readings, let the slab dry with dehumidification and air movement, and test again until the numbers are within the system’s limits. Only then do we grind, repair and coat.
A coating is never flood protection, and we do not sell it that way. What a well-built coating does offer after a flood is a surface that cleans up easily if water returns, without carpet or wood to tear out.
Building a Basement Floor That Lasts
Primers, Base Coats and Topcoats
Every basement floor is diamond ground to a measured ICRI profile, never acid etched. Where readings call for it, a moisture-mitigation primer goes down first to manage vapor rising through the slab. A 100% solids epoxy base coat builds thickness, and a topcoat adds abrasion and stain resistance.
The system is named in the proposal with its finished thickness, so you know exactly what is on your floor. Each layer is timed against slab temperature and dew point, not just the clock.
Finishes for Playrooms, Gyms and Workshops
A coated basement can become a playroom, home gym, workshop, laundry area or storage space with a floor that wipes clean. Smooth solid colors suit play areas, flake broadcasts hide dust and wear, and textured finishes add grip in gyms and laundry rooms. Lower sheens hide scuffs under rugs and furniture.
We help you match the finish to the room, then build it to the thickness the use demands. A workshop with rolling tool chests needs more body than a reading nook.
Radon and Basement Coatings
Rock County sits in EPA radon Zone 1, and Rock County Public Health has reported that about half of the homes it tested were above the health advisory level. A floor coating is not radon mitigation, and we never present it as one. Testing and a mitigation system are a job for a radon specialist.
If you have a mitigation system, we coat around its pipe and sealed sump lid without disturbing it. If you have not tested, it is worth doing before you finish the basement.
- 20+ Years in Concrete Coatings
- Moisture Testing in Every Scope
- Free Written Estimates