How to fix a squeaky stair, from below and from above

A squeaky stair is not a mystery. It is two pieces of timber moving against each other where they should be held still. To understand why that happens, the timber movement page covers the seasonal side and how a staircase is joined covers the wedges and glue blocks that do the holding. This page is the fix. The good news is that most squeaks are harmless and cheap to sort. The only real question is whether you can get to the underside of the stairs.

Find it first

Before you fix anything, pin down exactly where the squeak is. Get someone to walk slowly up and down and then rock their weight on each step while you watch and listen, ideally from underneath if there is a cupboard or open soffit. Work out which step it is, and whether the noise comes as the front of the tread meets the riser, at the back, or out at the wall string. A squeak nearly always traces back to one specific joint, and fixing the right one is the whole job. Mark it with a bit of tape so you do not lose it.

The proper fix: from underneath

If you can reach the underside of the stairs, through an understairs cupboard or an open soffit, this is where the real repair is made, because you are working straight at the joint. Three things to look for and put right:

1. The wedges. Each tread and riser is locked into its housing in the string with a glued timber wedge. Over time a wedge can shrink or work loose. Knock it back in, or replace it with a new glued wedge, so the tread is pulled tight into its housing again.
2. The glue blocks. Small triangular blocks glued into the angle where the tread meets the riser stop the two flexing apart. Old ones come loose or fall off. Clean the corner, run a bead of glue, and fit fresh blocks, rubbing them into place so they grab.
3. The tread-to-riser joint. Where the back of a tread meets the top of the riser, a couple of screws driven through from behind, into the tread, pull the joint solid and kill the movement for good.

Fixed from below like this, a squeak usually stays gone, because you have dealt with the cause rather than covered it.

If you cannot get underneath: from above

On most stairs the underside is plastered in, so you have to work from the top. It is still a good fix if you are careful:

1. Locate the loose tread as above, and find the riser below it and the strings at each side, which is where there is solid timber to screw into.
2. Pilot and countersink a hole down through the tread into the top of the riser below, or into the string, so you do not split the timber. Then drive a screw to pull the tread down tight.
3. Hide the fixing. Countersink deep and fill over the screw, or drill for a small timber plug or pellet cut from matching wood, so the repair disappears. On a carpeted stair the fixing simply sits under the carpet.
4. For a rubbing squeak where a tread and riser are just chafing, working a little talcum powder or powdered graphite into the gap can quiet it as a quick fix, though it is a patch, not a cure.

When it is more than a squeak

Know the difference between a noise and a fault. A squeak from a tread is friction, and benign. But if a whole tread flexes noticeably underfoot, if a newel post has worked loose, or if the banister moves, that is not a squeak to silence, it is movement in something that is meant to be solid, and on a staircase that carries a safety job. A loose handrail or spindle is often just a screw, but a moving newel or a springy tread is worth getting looked at rather than papered over.