Originally Posted by
Bloss
You need to look underneath see whether you have gaps at all between joists & bearers or bearers & stumps or piers. If they are obvious then you need to pack those - hardware stores will sell you plastic wedges of different sizes that are good for this if there is a gap more than few mms.
If it is a smaller gap or if the movement is between the YT and the joists (most likely) then a temporary fix that will last some time (at least 7-10 years usually) is to use building adhesive squeezed along both edges of the joist in the corner formed where the YT meets it - in the areas of movement.
A nuisance job if access is poor, but if you use ahead torch to see what you are doing and try to force the adhesive well into the corner it will fill the gap and remains semi-flexible. Works on T&G floorboards too.
Then when you are replacing the carpet at some later time you can punch, nail or screw.
It is not uncommon in older buildings for a squeak to come from the yellow plastic tongue itself as it mostly not supported and over time the plastic hardens and shrinks slightly. Not always, but sometimes, silicon sprayed into the join line from underneath helps. A more permanent fix is to glue and screw 60mm wide strips of timber (or even YT flooring cut into strips) under the join line to restrict the slight movements that causes the squeak.