Testing Radon Before & After Epoxy Floor Sealing in Katy TX

Pre-Installation Test Protocol

Test radon before floor installation to establish a baseline. Use a short-term charcoal canister test (48–96 hour exposure) or a long-term alpha track test (90 days) for more accurate results. Place the test in the garage, 6–12 inches above the floor, closed garage door. The result tells you starting radon load and whether epoxy alone is likely to be sufficient or whether sub-slab depressurization is needed.

Post-Installation Test Timing

Wait at least 30 days after epoxy installation before post-testing. The epoxy needs time to fully cure and stabilize. Run the post-test under the same conditions as the pre-test (same time of year, same closed-door protocol). This ensures the comparison is apples-to-apples and not affected by seasonal variation in soil gas pressure.

Realistic Reduction Expectations

Based on EPA data and customer feedback, epoxy floor sealing typically reduces radon concentrations by 20–50% when the floor was the primary entry point. Reduction is higher when cracks were significant entry points that are now sealed, and lower when wall-floor joints and pipe penetrations (not addressed by floor coating) are the main pathways. If post-test results remain above 4 pCi/L, sub-slab depressurization is the next step.

When to Call a Certified Mitigator

If your pre-test shows radon above 4 pCi/L, or your post-epoxy test still shows above 4 pCi/L, engage a certified radon mitigator. The EPA Action Level is 4 pCi/L. A certified mitigator can install sub-slab depressurization, seal the wall-floor joint, and test to confirm mitigation. We can coordinate timing with epoxy installation — often the mitigator's pipe penetrations are made before the floor coating is applied.