Step 20 - Subfloor
How to Test for Moisture Issues
Moisture is the silent killer of flooring. High moisture causes warping, mold, and adhesive failure. Testing takes minimal time and could save thousands.
Time needed
24-72 hours
Cost
$30-80 (moisture meter)
Difficulty
Easy
Testing Methods
Wood Subfloors: Moisture Meter
Use pin-type moisture meter. Wood should read 10-13%. Above 15% indicates problems.
- • Test multiple locations across floor
- • Focus on exterior walls and plumbing areas
- • Record all readings
- • Moisture meters cost $30-80
Concrete: Plastic Sheet Test
Simple 24-hour test reveals moisture vapor issues.
- 1. Tape 2x2 foot plastic sheet to concrete
- 2. Seal all edges with duct tape
- 3. Wait 24 hours
- 4. Check for water drops or condensation
- 5. Moisture = need vapor barrier
Next Step
If tests show moisture, install a moisture barrier before flooring.