How must a painter evaluate the condition and identify defects of substrates before painting?

• A. By applying a primer first
• B. By performing specific visual inspections and physical tests on the substrates.
• C. By guessing based on experience
• D. By measuring room humidity

Answer: (B)

Before painting, assess the substrate by visually inspecting it and performing practical tests to identify defects that could affect adhesion and the final finish. Visual checks reveal issues like cracks, peeling or blistering paint, chalking, stains, mold or mildew, oil or grease, dust, and surface contamination, as well as irregularities in texture or cleanliness that will influence how you prepare the surface. Physical tests confirm what the eye can’t fully tell you: how well the surface will hold primer and paint. This includes checking moisture content in concrete or wood, assessing surface adhesion with a patch or scrape test, evaluating surface porosity and profile, and, when relevant, testing pH on certain substrates. Knowing these conditions guides repairs, cleaning, patching, sealing, or moisture control and helps you choose the right primer or sealer. Applying primer before you’ve identified and addressed defects risks sealing in problems and could lead to failures later. Guessing is unreliable, and while room humidity matters for curing, it does not substitute for a proper substrate evaluation.