Painting skirting boards

[MyBalletShoes]

Just had some skirting boards put into a conservatory. They're already in a white finish but are slightly scuffed and unfinished on the edges where they've been cut to join together. So, they need painting again.

Does anyone know if I need to sand them first? Or if I can just do a coat over the top of the already very smooth white finish? I know the paint needs to cling to a grain which the sanding will enable so I'm leaning towards yes. It's just that the boards are already finished so to speak except for these small bits and marks where they've been cut to fit

Any help greatly appreciated!

We had ours done recently and he didn’t sand, but used a primer. Could have been cutting corners but it’s held up so far! It was originally a faded white gloss and he did primer, then new white gloss.

Thanks @Kismett

Primer sounds like an option as they only need a light coat to cover the small imperfections in the joins.

If it’s not a big job, sanding shouldn’t take too long. You’d just want to rough up the surface a little and wouldn’t need to do anything too serious. Good luck either way!