The quarter-landing at the top of our stairs (ie top of stairs by bathroom door, with a further step to left onto main landing) has one floorboard that's very springy and dips down when trodden on. I’ve had a look at it and it doesn’t seem split or broken, just… bouncy. We’ve got new carpet coming this week and we’re worried that either the board movement will eventually lead to uneven wear on the carpet or that the board movement will worsen / finally give way after carpet’s down and then fixing will be a pain. Any ideas on a simple (very simple, given my DIY skills…) solution? I’ve seen online suggestions of just fixing 3mm / 5mm plywood over the whole area (though I’m wary of that given there’s a lot of doorframe mouldings potentially to shape for, plus I don’t know how that would work in terms of the nose of that top stair). My first thought was to try to whip out offending section of board (they’re not tongue and groove) and replace, but not sure how easy it would be to get it out / slot the replacement length back in. Any suggestions / tips / solutions gratefully received..!