How to Perform a Roof Coating Adhesion Test: Step-by-Step with Scott Caprio
Introduction
Before applying any roof coating system, one of the most important steps in the preparation process is performing an adhesion test. This simple test helps determine whether a coating will properly bond to the roof’s existing surface — and it can save thousands of dollars in potential failures down the line.
In this article, Scott Caprio, Technical Sales Director at United Asphalt Company, walks through the process of performing an adhesion test and explains how to interpret the results.
Why Adhesion Testing Matters
Even the best roof coatings depend on proper adhesion to perform as intended. If a coating doesn’t bond well to the substrate, it can peel, blister, or delaminate — often within months of installation.
An adhesion test helps confirm that your chosen coating will:
- Adhere strongly to the existing roof surface
- Withstand environmental stress such as expansion, contraction, and UV exposure
- Deliver long-term protection without premature failure
Testing before full application ensures your coating system will last — and that your restoration investment is sound.
Step-by-Step: How to Perform a Roof Coating Adhesion Test
1. Inspect and Select Test Areas
Begin by inspecting the roof and identifying a few small areas (typically 6–8 inches wide) that represent the overall condition of the surface.
2. Apply Sample Coatings
Choose a couple of coatings you’re considering for the project. Apply each coating to a small test section of the roof substrate.
3. Embed Reinforcing Fabric
Place a strip of reinforcing fabric into the wet coating, leaving about 6–7 inches uncoated. This uncoated portion will be used later during the pull test.
4. Allow Proper Cure Time
Let the coating cure completely — typically a few days — depending on temperature, humidity, and product specifications.
5. Perform the Pull Test
Attach a fish scale or similar pull device to the uncoated end of the fabric. Slowly pull upward to measure the amount of resistance before the fabric separates from the substrate.
6. Evaluate the Results
- Passing Grade: Anything over 6 pounds of resistance is typically acceptable.
- If the coating splits in half and leaves material behind on the substrate, that’s ideal — it shows strong adhesion.
- If the coating lifts easily or the reading is below 5 pounds, consider another product or additional surface preparation.
Interpreting Your Adhesion Test Results
Strong adhesion indicates that the coating system is compatible with the existing roof surface. Weak adhesion, on the other hand, suggests that the roof may need additional prep work such as cleaning, priming, or repairs — or that another coating formulation should be considered.
Skipping this test can lead to coating failure, leaks, or early roof replacement — all of which are far more expensive than spending a few hours testing first.
Final Thoughts
Adhesion testing may seem like a small step, but it’s one of the most critical parts of any successful roof restoration project. It ensures compatibility, saves time, and protects your investment by preventing costly coating failures.
If you’re planning a commercial roof restoration or want to learn more about choosing the right coating system, reach out to the Armour Proof Coatings team at United Asphalt Company for expert technical support and product recommendations.
