How do I fill this gap?

[Diydolly36]

Without using expanding foam. It's where the skirting board meets the floor. I'm going to caulk the small scruffy gaps but this floorboard has been cut short & I don't want to lift it now I've started painting the floor. I was thinking a gluey pva'd twist of newspaper tied to a piece of string could be poked through & pulled taut until it dried & then the gap caulked, but has anyone got a better idea?

[lalalonglegs]

I second caulk - don't get too technical with it, just squeeze it in and then smoothe it off.

[Diydolly36]

To be clear, I have to poke something into the gap first as there's nothing behind just a void to the sub-floor. Caulk is fine for the front after I've managed to plug the behind, otherwise it'll just fall through. Any ideas?

[wowfudge]

Just plug the gap with scrunched up newspaper then use caulk over the top.

[lalalonglegs]

Piece of cardboard? I'd be tempted to cut the nozzle of the caulk into a large hole and see if I could just fill it with a thick squirt - it's so sticky I doubt it would just fall down. The gap doesn't seem huge.