To stop a subfloor under a carpet from squeaking without having to remove the carpeting, use a kit such as the one from Squeeeeek No More which includes a long screw to find the floor joist.
Next, use the guide to drive a special screw that pulls the subfloor down tight against the floor joist, then can be broken off below the surface of the carpet.
Watch the video above to find out more.
VIDEO TRANSCRIPT
Stopping a squeaky floor under carpet begins with finding the floor joists beneath the surface. This kit includes a long screw which is only threaded for the first inch. When you drive it into the floor, it won’t back out without pulling on the washer if there’s no joist there. When you find the spot, you set the kit’s guide over it, and drive in their special screws. The guide stops the screw at the proper depth so you can snap it off beneath the surface, holding the subfloor tight and stopping the squeak with no fasteners visible at all.