Choosing paint is a technical decision. The right coating depends on the substrate, exposure, expected wear, appearance, maintenance needs and project specification. A product that works well on interior drywall may not be suitable for exterior masonry, a metal handrail or a high-traffic floor.
Common coating families
- Waterborne acrylic/latex: common for many interior and exterior architectural applications, subject to product limitations.
- Alkyd and solventborne: used in some trim, metal and maintenance systems; solvent exposure, ventilation and fire precautions matter.
- Primers and sealers: designed for particular substrates or conditions such as porous surfaces, stains or adhesion needs.
- Epoxy and urethane: specialty systems used for selected floors and protective applications; mixing ratios, pot life and PPE can be critical.
What a primer does
A primer may promote adhesion, seal a porous substrate, improve uniformity, block certain stains or provide corrosion protection. Primer selection must match the substrate and the finish system. Primer is not a universal fix for damp, dirty or structurally unsound surfaces.
How to read a technical data sheet
- Approved uses and substrates.
- Surface preparation and primer requirements.
- Mixing instructions and pot life for multi-component products.
- Application tools and thinning restrictions.
- Coverage range and wet-/dry-film thickness.
- Air and surface temperature, humidity and other application limits.
- Drying, recoat and full-cure times.
- Cleanup, storage and disposal instructions.
Understand VOC categories
Volatile organic compounds (VOCs) can be emitted by coatings and solvents. Limits vary by coating category and local air district. In the South Coast AQMD area, Rule 1113 regulates architectural coatings. Use the South Coast AQMD architectural coatings page and its product database to research applicable products and categories.
Student exercise: Select two products intended for the same substrate. Compare their approved uses, preparation requirements, coverage, recoat window, film thickness and VOC category. Explain which one best matches a hypothetical project specification—and why.
