Do I need to sand white internal doors if I want to just repaint them white?

[DIYagainstMould]

Hello,

We have white internal doors and winter time mould which disappears in summer. The doors get very filthy and I wipe them but would like to repaint them myself each summer, just for fun. Can I just do this without sanding and washing with anything? Thank you

Yes but only a little bit, just to scratch the surfaced so that the new coat sticks. Wash them first with washing up liquid to get any grease off because the paint won't stick otherwise.

I did all mine (22 of them) a few years ago.
I did wash them down well with sugar soap but didn't sand, apart from where some hooks had been which I filled and sanded.
Paint went on, and has stayed on, fine.

And I said at the time I was never doing them again!

Just a light sand. Think a couple of minutes per side, nothing strenuous. Use 120-150 grit ie medium grade sandpaper. Edit to add, get any old lumps and drips out from previous painting at this point, can be a few of those esp on panel doors.

And yes sugar soap will be better than washing up liquid but either will do as long as it’s clean. I prefer to use a combination of brush and mini roller for doors. Brush alone can leave brush marks if you’re not careful.