How to stop stairs creaking from underneath

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Creaky stairs can be infuriating, particularly late at night and early in the morning. However, the problem isn't always easy to solve. The main causes of squeaking stairs are the shrinkage of the timber treads over time, and general wear and tear. 

How to stop stairs creaking from underneath

The tread(s) can start to rub against the top of the riser causing a squeaking or creaking noise.  Any adhesive originally used to bind the treads and risers together may also have become unstuck. This is normally just an annoyance, rather than anything seriously wrong with your staircase.

There are several methods of addressing or even eradicating these squeaky steps.  In most cases the best results are obtained by repairs from the underside of the staircase. This is not always feasible as sometimes the staircase is blocked off from the rear.  It is, however, also possible to repair from the front of the staircase.Let's assume for the moment that the rear of the staircase is not accessible and that we need to tackle the problem from the front of the staircase. There are three main methods of tackling loose treads from the front:

  1. Screw down loose treads

  2. Nail down loose treads

  3. Add a moulding or quadrant for support

 

The best method of securing the treads to the risers is to screw them down. Normally, three screws per tread are more than sufficient. 

Before mounting the screws, you will need to pre drill holes through the tread level with the riser. We recommend using 38mm  No.8 countersunk screws. Once the screws are in place, make sure that they are countersunk below the surface of the tread. 

If the staircase is exposed (i.e. no carpeting), for the neatest result it's best to use an appropriately coloured wood filler to conceal the screws. 

How to stop stairs creaking from underneath
 

For a more professional approach, you could use a plug cutter and screwsink set to properly disguise a countersunk screw. This process is detailed below:

 
How to stop stairs creaking from underneath
 

Using a block of wood which is of identical type to the tread, use a plug cutter to rout out a woodplug with the same diameter as the screwsink (left).

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

How to stop stairs creaking from underneath

       
 
How to stop stairs creaking from underneath
 

Use a thin chisel to chip out the formed woodplug as shown (left).

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

How to stop stairs creaking from underneath

       
 
How to stop stairs creaking from underneath
 

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

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

How to stop stairs creaking from underneath

       
 
How to stop stairs creaking from underneath
 

Leave the glue to dry for a few hours.  Once this is complete, use a sharp chisel to slice off the bulk of protruding woodplug (left).

Finally, sand the rough top of the woodplug so it is perfectly flush with the top of the tread (right).

How to stop stairs creaking from underneath

     
 

For MDF treads and risers, a slightly different approach is required. No pre-drilled holes are needed for MDF, as it is recommended to use special MDF screws. These have the added benefit of not splitting the MDF board, as can occur when drilling pilot holes or using unsuitable screws.  

Using normal 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.   

How to stop stairs creaking from underneath
     
How to stop stairs creaking from underneath

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

Please Note the dovetail arrangement in which the nails are inserted, which 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.

If a loose riser or tread is found, it is also possible to glue on a moulding or quadrant. This long piece of wood can be glued either at the top of the rise or the bottom, or indeed both. For extra adhesion, we also recommend pinning 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 a good idea for aesthetic reasons to add these mouldings to all the treads.

How to stop stairs creaking from underneath

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

  1. Attach glue blocks

  2. Replace worn or missing wedges

  3. Insert small slip wedges

       
How to stop stairs creaking from underneath

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 (left).

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 (right).

How to stop stairs creaking from underneath

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

How to stop stairs creaking from underneath

First, 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 adhesive (left).

Second, place the glue block into position as shown and line up the securing screws ready (right).  

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

How to stop stairs creaking from underneath
How to stop stairs creaking from underneath

Finally, taking care not to push the screw through the tread or riser, carefully drive in the screws. 

If you have someone to help, get them to stand on the tread while you drive the screws home. The extra pressure will help keep the tread nice and tight against the glue block.

As an alternative to glue blocks, or indeed in addition if there is enough room, you could add small rectangular blocks to the corners of the stairs to secure the treads to the strings, as shown on the right.

The screws are at right angles to each other, one boring into the bottom of the tread and the other into the string. Again, it is recommended that the blocks be coated in glue and moved around back and forth on the surface of the wood to eliminate any air pockets in the adhesive.

How to stop stairs creaking from underneath
How to stop stairs creaking from underneath

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 on the left makes this clear.

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.

How to stop stairs creaking from underneath
How to stop stairs creaking from underneath

Inspect the rear of the staircase. If you find any loose or worn wedges, gently chip out the old wedge with a chisel. Should the wedge be too damaged to refit into the mortise, new wedges can be purchased from our on-line shop .

Coat the new replacement wedges with glue and use a mallet to gently drive the new wedges into place. In addition, before fitting the new wedges, inject some adhesive into the mortise - that way, when the wedge is inserted again, the tread or riser will bond with the glue in the mortise and provide extra grip.

Another method of effectively tightening the joints between the tread and riser is to insert small 'slip' wedges into the joints. The procedure of inserting these wedges varies, based upon what types of joints the tread and risers are connected with. Each wedge should be about 30mm long and tapered down from 3mm to a point. Apply some glue to the wedges and insert them as follows according to your stair joints: 

 
How to stop stairs creaking from underneath
 
How to stop stairs creaking from underneath
 
How to stop stairs creaking from underneath
 

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

 

At Pear Stairs we sell a number of products to finish your staircase. If you have any questions don't hesitate to phone our friendly team on 01938 553311 for expert advice, or click on the Contact Us button to get in touch by email.

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