Can squeaks be fixed during new flooring installation?

The decision is about timing, not whether it can be fixed

A squeak is almost always two layers of wood rubbing where a fastener has backed out slightly, and the mechanics of that are covered in full elsewhere. The more useful question, if new flooring is already happening in that room, is not whether the squeak can be fixed at all. It is whether this project is the moment to do it, or whether it is really a separate repair that happens to share a room with an installation.

Option one: fix it while the old floor is already coming up

If the floor over the loose spot is being removed anyway, the subfloor is exposed for a stretch of time it would not otherwise be. That is about as easy as a squeak repair ever gets, because nothing has to be opened up specifically to reach it, and the diagnostic work of walking the room and listening board by board happens naturally while the old material is coming out. Re-securing the panel to the joist at that point adds a few extra fasteners to work that is already underway rather than starting a repair from scratch. This is the option worth raising early, ideally before the crew arrives, so it is expected and planned for rather than discovered partway through the day.

Option two: fix it from below, on its own timeline

If there is a basement ceiling or an open crawlspace under the room, the loose spot can be re-fastened from underneath without touching the finished floor above it at all. That route does not depend on new flooring happening on any particular schedule. It can happen before the installation, after it, or completely separately, because the access lives below the room rather than inside it.

Option three: let the new floor quiet it without curing it

When neither of the first two is available, a stiffer, rigid-core material can genuinely make a mild squeak less noticeable, because it resists transmitting the small movement the way a thinner or more flexible surface would. That is worth understanding honestly: the loose fastener is still loose. The floor is dampening the sound of it, not repairing it, and a squeak handled this way can return, sometimes in a different spot, once everything above it has settled in.

What actually decides between the three

Whether the old floor in that exact spot is coming out is the first fork. If yes, option one is nearly always worth taking, since the labor of opening the subfloor is happening regardless of the squeak. Whether there is a basement or crawlspace below is the second fork, and it can make option two available even when option one is not, or as a way to handle a squeak in a room that is not being touched at all. If neither applies, and the noise is minor and confined to a low-traffic spot, letting the new material quiet it is a reasonable, honest choice, so long as it is chosen rather than assumed.

Where this decision does not extend

This is about a squeak in a room where flooring is already being installed, or where access already exists from below. It is a different situation from a squeak in a room with no project planned and no way to get underneath it, which is really its own repair rather than something to fold into an unrelated job. It is worth naming that boundary honestly, because forcing a fix into a room that offers neither access from below nor a reason to open the floor means creating that access first, which is a repair in its own right rather than a detail folded into work already happening. And a squeak that comes with real give or spring underfoot, not just noise, is a different question again, one worth a direct look before any material choice gets made, rather than something any of these three options is meant to address on its own.