Squeaking stairs help

[ih]

Hi! 1930 built house semi with squeaking stair case currently carpeted ( i know this has to come off to do repairs) 13 steps in total there is meter cupboard underneath and the stairs are boarded with t&g and the toilet next to it toilet is tiled inside so no access to underneath the stairs in that area chippy who came few days ago says cutting t&g upto the partition to the toilet will be required to access to the wedges which is fine that means 8 treads can be fixed from underneath he is of opinion that stairs repairs from top are no no! I have seen website which says fixings/adhesive are possible from top! ( when chippy came i was out my oh attended)
Any help advise will be appreciated
Thanking in advance
Ih some poor photos with apology

 

[Burnerman]

You really need to get to the underside of the stairs to do a thorough job- the chances are the wedges will be loose or have maybe fallen out.
However you can screw through the treads into the risers which will help a bit. The trouble is you can't do the same at the bottom of the riser. I have screwed through the outer stringer before, directly into the tread and riser......it didn't cure things completely but it did help.
John