How to fix squeaky stairs

The main causes of squeaking stairs are the shrinkage of the timber treads over time, along with general wear and tear. 

Treads can start to rub against the top of the riser causing a squeaking or creaking noise. Adhesive originally used to bind the treads and risers together may also have failed. This is normally just an annoyance, rather than anything seriously wrong with your staircase.

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There are several methods of addressing or even eradicating the squeak.

In most cases the best results are obtained by repairs from the underside of the staircase. This is not always feasible as sometimes the underside of the staircase is blocked off.

It is, however, possible to repair the staircase from above.  There are three main methods of tackling loose treads from the front.

 Solving the squeak from above the stairs

1.

Secure with screws

The best method of securing the treads to the risers is to screw them down. Usually three screws per tread should be more than sufficient. 

Drill pilot holes through the tread and in line with the riser. 

We recommend using No.8 x 38mm (1 7/16") countersunk screws.

Ensure that the screws are countersunk below the surface of the tread. Use a countersink bit if necessary. Some screws are ribbed under the head and will cut their own countersink. If unsure, test on a piece of similar scrap timber. 

If the staircase is to be left exposed (i.e. no carpet) it is wise to use an appropriately coloured wood filler to conceal the screws. 

For a more professional finish, use a Plug Cutter and Screwsink set to properly disguise the countersunk screws.This process is detailed below:

A set of two Plug Cutters and screwdiggers for No.8 and No.10 countersunk woodscrews.

As listed on our Wonkee Donkee Tools website.

You will need a block of timber which is of identical type, colour and grain as the tread.

Use a plug cutter to route out a woodplug with the same diameter as the screwsink.

The woodplug is formed in the block and now needs to be cut out.

Use a thin chisel to "chip" out the formed woodplug as shown.

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Now, using a screwsink (or screwdigger), drill out the pilot hole for the countersunk screw, through the tread into the top of the riser.

Screw the countersunk screw into the top of the tread and through into the riser.

With the tread secured, cover the hole left by the screw with the plug you produced earlier. Cover the base and sides of the block with wood adhesive. Make sure you align the woodgrain of the plug with the grain of the tread.

Leave the glue to dry for a few hours, then, using a sharp chisel, slice off the bulk of protruding woodplug.

Finally, sand the rough top of the woodplug until it is perfectly flush with the top of the tread.

For MDF treads and risers, a slightly different approach is needed. 

Pre-drilled pilot holes are not required when screwing into MDF when using specially designed MDF screws. Unlike ordinary screws, MDF screws are designed to be used without pilot holes, and so will not split MDF board. 

Using ordinary screws designed for Hardwood or Softwood can cause the MDF to bulge and eventually split.

The secret of the MDF screw lies in its structure; a serrated thread allows it to cut cleanly through the board without bulging or splitting the wood:

2.

Nailing Loose Treads.

One of the simplest repairs is to nail two nails (or more if needed) into the centre of the edge of the tread, where they meet the riser as shown below.

Note
The "dovetail" arrangement in which the nails are inserted gives the nails better grip on the wood.
Take care not to split the wood or pierce the edge of the riser with the nails.

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3.

Using A "Moulding" Or "Quadrant".

If a loose riser or tread is found, it is also possible to glue on a "moulding" or quadrant". The length of moulding can be glued either at the top of the riser, the bottom of the riser or both. We recommend that you pin the moulding to both the riser and the tread. 

This method is used as a more aesthetically pleasing alternative to simply nailing or screwing the treads and risers together, but it does require a bit more precision work. If the staircase is exposed (no carpets) it is recommended for aesthetic reasons to add these mouldings to all of the stairs - not just the squeaky ones.

Solving the squeak from underneath the stairs.

If, on the other hand the rear of the staircase is accessible, more effective repairs can be made to the stairs.

These are as follows:

1.

Glue Blocks.

A successful method of strengthening the joints between riser and tread is to use "glue blocks". These are triangular shaped small wood blocks, which can be made easily by sawing a square block in half down the diagonal. 

Four small pilot holes are drilled into the block at right angles to each other, as shown below:

The glue blocks need to be placed near each corner (and one in the middle on wider staircases) where the tread meets the top of the riser:

Install the glue blocks with the help of these three simple steps:

Firstly apply some PVA glue to the glue blocks. It is important to move the glued block back and forth to rid of any air pockets within the glue.

Place the glue block into position as shown and screw in the securing screws.

Remember to use MDF screws if you have MDF treads and risers.

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Alternatively, glue and screw string blocks (small rectangular blocks of timber) to the corners of the stairs to secure the treads to the strings. These can be used in addition to the glue blocks to give added strength and rigidity.

The principle of string blocks is essentially the same as glue blocks, but they are used to fix the ends of the treads to the strings. 

The screws are fixed at right angles to each other, one pair boring into the bottom of the tread and the other pair into the string. It is recommended that the blocks are glued then moved back and forth on the surface of the tread and string before screwing to eliminate air pockets in the glue.

2.

Replacing Worn Or Missing Wedges.

If the staircase is built into a housed string system, it most likely contains securing wedges for the risers and treads. These wedges would have been placed in the staircase when it was originally constructed.

They are used to butt the risers and treads up against the mortises of the housed string so that no gaps are visible between the strings and the treads and risers.

The drawing below summaries this:

Over time and extensive use of the staircase, the wedges can slip or become damaged. This can also lead to the dreaded "creaking" or "squeaking".

A slipped or damaged wedge can normally be spotted if there is a gap showing on the staircase between the tread and/or riser and the string mortise:

If possible, inspect the rear of the staircase for loose and damaged wedges. Gently remove all damaged wedges with a chisel. 

Inject adhesive into the mortise and coat the replacement wedge with adhesive. Use a mallet to gently drive the wedge into place. 

3.

Insert Small "Slip" Wedges.

Another method of effectively tightening the joints between the tread and riser is to insert small "slip" wedges into the joints.

The way in which these wedges are inserted into the joint will depend upon the type of joint that connects the tread and risers.

Each wedge should be about 30mm long and tapered down from 3mm to a point. Apply wood adhesive to the wedge, and insert according to the following joints: 

Once the adhesive has dried, use a sharp chisel to trim off the ends of the protruding wedges.

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Conclusion:

To completely eliminate squeaking treads, you may need to employ a combination of some or all of the above methods - glue blocks, string blocks, wedges and screws.