Guide
Subfloor readiness
Flatness, moisture, and why prep is half the job.
Flatness
Most click floors want tight flatness tolerances. High spots telegraph; low spots open joints.
Moisture
Concrete slabs need testing. Wood subfloors need dry structure and the right vapor strategy.
Movement joints
Buildings move. Floors need expansion space at walls and fixed objects.
When to call a pro
If the slab is a lake, the joists bounce, or height transitions look like a skate ramp — pause the DIY.