Can I fill this gap with something?

[FFCForever]

Hi all,
I have a reasonably sized gap in my bedroom floor between the floor boards and the wall, maybe about 3cm wide. I recently lifted up the carpet etc and and still to replace the skirting but this bedroom is above another room that has a TV in it etc and it would be nice for soundproofing etc to fix it up a bit.

I wondered if I should just ram some insulation in there or perhaps some expanding foam (not all too keen on that idea as it’s messy).

Any suggestions?

 

[oldbutnotdead]

Doesn't look like 3cm. 3mm maybe...
Ram some rockwool in there. Exp foam would be a pain in a gap that small, need about 10mm to do anything useful with the stuff

 

[Why Not Indeed]

If the gap in that picture is 30mm, then that screw head is about 15mm across, which seems unlikely. Anyway.
I have seen recommendations from @JobAndKnock for "Compriband" tape - this might well work here. No mess and you're unlikely to accidentally hoover it up unlike rockwool. It will be a lot more expensive for the same coverage, though [especially as I wouldn't be buying a whole roll of rockwool just for this, I would just nick a bit out of the loft ]

 

[Deleted member 174758]

Compriband is a compressed, closed cell foam which expands from about 4 to 10mm (compressed size) up to between 10 and 50mm, depending on the tape chosen. We used it throughout a mill refurb (over 100 apartments) where some of the floors terminated at an original (stripped) brick wall, to fill the gaps between the edges of the laminate flooring and the brickwork. It needs a two solid surfaces in the same plane to expand into, e.g. a floor edge and a masonry wall, and it is expensive, but it works very well. If your gap is 30mm between the edge of the floor and the bottom of the skirting it probably won't work as the second solid surface in the same plane as the edge of the floor is going to be the wall, which might be 25 to 50mm behind the front face of the skirting

Any possibility of a photo from slightly further back with an object, such as a coin or the like, for scale?