Surface Preparation and Substrate Assessment
What the domain tests
Surface Preparation and Substrate Assessment tests whether you can judge a substrate as clean, sound, dry, flat, and compatible before covering it. The domain covers concrete, wood, existing flooring, patching, profiling, moisture and pH testing, and repair documentation. The exam favors test methods and the principle that manufacturer tolerances control.
Core rules and concepts
- Concrete: remove curing compounds, paint, adhesive residue, and loose material; patch and profile per the covering manufacturer. ASTM F710 is a common preparation reference for resilient flooring.
- Moisture: use the specified test. ASTM F2170 measures in-situ relative humidity in concrete; ASTM F1869 is the calcium chloride test. Do not substitute a plastic-sheet test for a required quantitative method.
- pH: test concrete alkalinity; high pH can affect adhesive. Record readings by location and date.
- Wood: verify joist spacing, deflection, panel thickness, gaps, fasteners, and moisture content. Correct movement and squeaks before covering.
- Flatness: check with a straightedge or specified method. Typical resilient tolerances are tight, often stated in fractions of an inch over 10 ft; use the manufacturer's number.
- Existing floors: identify asbestos-era material, test if required, and do not cover unstable or wet substrate.
Worked example
A 1,000 sq ft slab gives an in-situ RH reading of 85% and pH 10. The specified adhesive allows 80% RH and pH 9. The slab fails both limits. Reasoning: patch cannot fix moisture; the fix is a manufacturer-approved moisture mitigation system, then retest before installation. Document readings and product batch.
Traps
Testing immediately after wet curing, taking one spot reading, covering a damp slab, using gypsum patch where a cementitious product is required, and ignoring pH are common errors.