Locate the exact squeaky area by walking slowly and marking the spot
Tighten loose subfloor screws into the joists from above if accessible
Drive screws through the subfloor into the joists to eliminate movement
Use a stud finder or joist locator to find joists before fastening
Add construction adhesive between subfloor and joists from below if exposed
Shim gaps between joists and subfloor from below with wood shims
Install blocking or bridging between joists to reduce flex
Replace damaged or warped subfloor sections
Secure loose hardwood boards with finish nails or flooring screws
Use a squeak repair kit designed for carpeted floors
Sprinkle powdered graphite or talcum in minor wood-on-wood rubbing areas
Refasten loose underlayment if it is the source of the noise
Check for and repair joist damage, rot, or termite issues
Remove and reinstall flooring if the squeak persists and access is limited
Hire a professional if the floor is sagging, damaged, or unsafe