Wood filler on stairs to be stain

[GoodOne]

Hi All,

I would appreciate if anyone could advise me on what sort of filler would be the best to fill up those gaps between the stairs?

Btw, I plan to strip off the paint and stain it.

.

 

[foxhole]

You could use wax filler crayon ( liberon) for small holes etc but gap between cannot be filled as there is movement when walked on which would break up any filler. You could use flexi sealant colour matched as used around laminate.https://www.screwfix.com/p/no-nonse...gclsrc=aw.ds&dclid=CIOjoNykrdoCFQUj0wodFxwHMA