It all must be stripped, properly prepped, primed and repainted, there is no easy fix. Anything put over that will just do the same thing, crack........................

I agree, it has to be stripped. Looks like someone painted over and didnt give previous coats a chance to dry completely before putting on more coats. Nothing will fix, but, to strip and sand, and prime properly and redo.

Oh no.....I hate the thought of stripping all that!! What's the easiest way to strip? Chemical?

Yes

An infrared paint stripper.

Get a good Palm-sander & some 100-grit sandpaper!

Screw the chemicals!

You'll have to sand ANYWAY after doing any stripping....

Faron

I'm the outlier. I wouldn't expend all that energy just to ultimately repaint it. If it really is just cracked and not peeling at all, I'd at least do a test section.... I'd coat it with a good primer and then give it a coat of white and see if that levels in the cracks. If it works for the test section, I'd continue with the rest, then hope it never cracks again. Or you could sand/strip a test section and see how much of your life you'd need to devote to doing the whole thing, just so you could repaint it, and reevaluate the situation. :)

Much better to use stripper on it, when you have no idea what is under it.