Should I nail or screw floorboards down?

A squeaking floor is almost always a board moving against a fastener. Over years, a nail polishes a slightly oversized hole for itself in the joist, and the board then rises a fraction under one foot and drops under the next. That tiny movement, against the nail shank, is the noise. A screw does not do this because it holds the board clamped rather than merely pinned.

Safety

Step by step

1. Choose screws for anything you want to stay quiet.A countersunk woodscrew long enough to get well into the joist without passing through it. In practice that means the board thickness plus roughly twice again, checked against the joist depth and against whatever is beneath.
2. Pilot and countersink in old or dense timber.Old, dry softwood splits readily, especially close to a board end. A pilot hole and a countersink take seconds and prevent both splitting and a proud head.
3. Set the head below the surface.A proud screw head snags a vacuum, wrecks a sanding belt and telegraphs through any covering laid over it. Countersink so the head sits just under, then fill if the floor is exposed.
4. Use two screws per board per joist.One screw lets the board pivot. Two, set in from each edge, hold it flat. On wide boards this matters more, not less.
5. Use nails only where they are the right answer.On a historic floor where cut nail heads are part of the appearance, or where you are re-fixing a board that will be lifted routinely and you want a fast fixing. Lost-head or cut floor brads, driven at a slight angle in opposing pairs, hold considerably better than a straight nail.
6. Never use plasterboard screws.They are hardened and brittle, they snap under the shear loads a floor puts into them, and the broken shank is then impossible to get out. Use proper woodscrews or purpose-made flooring screws.
7. Match the fastener to a chipboard deck.Chipboard flooring is screwed, not nailed, with a coarse-thread chipboard or flooring screw. Nails pull out of chipboard readily and the board then rides on them and creaks.
8. Consider secret nailing where the finish matters.Tongued and grooved boards can be fixed through the tongue at an angle, so the fastener is hidden by the next board. It is slower, only works on a new lay rather than a repair, and gives a completely clean surface.

Common mistakes

• Adding more nails to a squeaking floor — You are adding more of the thing that is causing the noise. Take the nails out or leave them and add screws.
• Using a screw long enough to reach the ceiling below — In an upstairs floor, an over-long screw comes through the ceiling plaster below, and in a service run it reaches the pipes and cables. Measure the joist depth and choose accordingly.
• Driving fixings without scanning first — The most common serious injury in floor work. Services are in the void by design, not by accident.

Questions people ask