The one page on this site that tells you how to fix something instead of just naming it. Everything else in Why Floors Fail needs a moisture meter, a power stretcher or real tile experience before it is safe to touch. A squeak is different — the fix is a screw in the right spot, and the risk of trying is close to zero.
Whatever is on top of the floor did not cause the squeak and mostly cannot fix it either. Almost every case is a fastener that missed the joist — or one that has since worked loose — letting the subfloor flex a fraction of an inch under weight and rub against the fastener shank, or a soft, uneven spot in the subfloor itself flexing across a joist.
Nailed hardwood and floating floors transmit that movement straight up. Carpet and its pad cushion the impact and muffle the sound, which is why carpeted rooms squeak less often — but a genuinely loose connection can still talk through carpet under enough weight. NWFA attributes most hardwood squeaks to inadequate subfloor fastening for exactly this reason, and calls for re-fastening rather than replacing boards.
Ten minutes of walking the floor tells you more than any guess. Where the noise is and how it is shaped decides which fix below actually applies.
Cross the room on the balls of your feet at normal walking weight, not tiptoeing. Mark every spot that talks with a piece of painter's tape as you find it — you will not remember the exact spot once you stand up.
One isolated spot is almost always a single fastener. A run of noise following a straight line across several boards points to one joist along its whole length. Noise scattered across the whole room, worse in winter, is more often subfloor shrinkage than a single bad fastener.
An unfinished basement or a crawlspace under the marked spot changes everything about the fix — it means working from below, never touching the finish floor at all. Without that access, the fix has to come from above, and the floor covering on top decides how.
Every one of these is the same fix — pull the subfloor tight to the joist — done differently depending on what you can reach and what is on top.
This is the easy case. Locate the marked squeak from above, then go underneath and find the same spot against the joist. Specialty subfloor screw kits are built exactly for this — designed to pull the subfloor snug to the joist from below without penetrating the finish floor at all, so there is nothing to patch or refinish afterward. This works the same way whether the floor above is hardwood, laminate or carpet, because the repair never touches it.
Find the joist under the marked spot with a stud finder, or drill a small test hole where trim will hide it. Pre-drill at an angle through the board, into the joist, and drive a trim-head screw below the surface. Set the hole with color-matched putty. This is straightforward on a nailed floor; a glue-down engineered floor is already bonded to the substrate and squeaks there are less common and less reliably fixed this way.
The same repair, adapted: specialty squeak-fixing screws exist specifically to be driven straight through carpet and pad without pulling the carpet back first, using a shank the fibers pass through cleanly. Find the joist the same way as for hardwood, then fasten through the marked spot.
The honest answer: this is the case with no clean fix from above. The panels are not fastened to the subfloor at all, so there is nothing to tighten without disassembly. If the noise is panel-to-panel friction at a joint, the practical options are lifting the affected section to address the subfloor underneath, or living with it. This is the scenario where prevention — getting the subfloor flat before the floor goes down — matters far more than any fix after the fact.
None of these are common. Most squeaks are exactly what they sound like: one small thing, in one small spot, with a small fix.
Usually, if you have access from below. From a basement or crawlspace, a specialty subfloor screw driven up into the joist from underneath never touches the finish floor at all. Without that access, nailed or stapled hardwood can be fixed from above with a pre-drilled, angled screw through the tongue into the joist. A floating floor is the hard case — the panels are not fastened to anything, so a joint that is genuinely rubbing usually means lifting the affected section rather than working through it from the top.
Almost always no. The overwhelming majority of squeaks are one loose fastener or one soft spot in the subfloor, not a sign the framing is undersized. It is worth a second look if the squeaking is widespread rather than in one or two spots, or if it comes with visible sag or a noticeable bounce underfoot — those point toward the joists themselves rather than a single fastener, and that is a question for a contractor or a structural engineer, not a screw.
It dampens the noise; it does not fix the cause. Carpet and its pad cushion the impact of a footstep, which is why carpeted rooms squeak less often than hardwood or laminate over the same subfloor. But the loose connection underneath is unchanged — enough weight in the right spot can still make it talk, and the fix is the same subfloor repair either way, not a thicker pad.
Only if one lands in the joist. A screw driven into open space between joists tightens nothing and just adds a hole — this is the single most common way people make an attempt and conclude the floor cannot be fixed. Find the joist first, with a stud finder or by drilling a small test hole where it will be covered by trim, then fasten there.