Mark Cooper
Hi Shona. I'm picturing this crack/split is in an older style skirting board with a shaped profile at the top. ie you possibly have an older home. It is more likely that this is a split along the grain of the board and has become apparent over time. If the surrounding area shows no sign of other damage, damp perhaps, then I would take the simple approach and use a filler(Polly filler is good) and fill the crack/split. Monitor it and if nothing more happens job done. If the skirting has a stain finish( not gloss painted) there are good natural wood coloured fillers available. I say this as Polly filer is white. Hope this is clear enough and helps you. Mark
