Squeaky floors upstairs

An upstairs floor is not just a floor. It is also the ceiling of the room underneath, and that dual role is why it gets noticed while a ground-floor squeak goes unremarked for years. When somebody walks across a bedroom, the subfloor flexes between the joists, and any connection that has loosened rubs. On a ground floor over a basement that noise dissipates into an empty space. On a second storey it radiates directly into the living room where somebody is sitting. The problem is compounded by house geometry. Common older Ontario house forms, the two-storey semi, the Foursquare, the postwar two-storey, all place bedrooms directly over living space with a staircase running up between them. There is nothing structurally wrong with that, but it means a squeaky bedroom floor sits over the room you use every evening. Access is the other half of the story: if the ceiling below is finished drywall or plaster, we cannot simply reach the joists, so the approach has to be chosen accordingly.

Because the ceiling below is usually finished, upstairs squeaks are normally fixed from above, and the floor covering decides how. The first step is finding the joists under the spot: rows of nail heads where the subfloor is exposed, a stud finder, or a measurement taken from a joist you can see through a heat register opening. Joists usually run 16 inches on centre, but that is checked, not assumed. Under carpet, a snap-off screw goes through the carpet and subfloor into the joist, the head breaks off below the surface, and the pile closes over it. Under hardwood, a pilot hole and a trim-head screw go through the board into the joist, and the countersunk head is filled to match. A floating floor must not be screwed down, because it is designed to stay unfastened, and tile is not screwed through, so a squeak under either is reached from the ceiling below or left alone if it is minor. If the joists are engineered I-joists, their makers forbid cutting, drilling or notching the flanges, so the fix is fastening down into the top flange and nothing is cut into the joist. Opening a ceiling is a last resort, and if it is needed you will know before any work starts, because it changes the scope.