Paint cracking on outside walls

[Tweed]

Hello. The paint on parts of my outside house walls is cracking, probably due to direct exposure of the sun. I've scraped off the paint in the offending areas and it's come off exposing the bare render underneath, leaving noticeable depth patches where the render meets the many layers of hardened paint surrounding them. Has anyone any suggestions to avoid the "crater" look once it's painted?

[heathfield]

Fill the craters with something like exterior Polyfilla before repainting?

[The Builder]

Polyfilla, as Heathy says, is the usual.
It rather depends on what type of paint it is though. The thickness you describe suggest that it might be several generations of cement basedpaint or limewash/whitewash. Modern paints tend not to come away from render quite so cleanly.
It makes no difference to how you deal with it. I only mention it because you usually have to go at it fairly hard with a scraper, otherwise more chunks are likely to keep coming away.
Anyway, an old trick is to thicken some paint with fine sand. Daub that on around the edges to lose the "step" in the paint thickness.

[Tweed]

Thanks for the tips folks. It's a 1930 house so I expect the many layers is of both old & new paint.

[Whickerman]

btw - more likely it's frost damage from that beeaatch of a winter.

[Tweed]

Ta much HeathField, WM (good point) & great answer from The Builder :)
God knows what's been on it since 1930. I was always a bit wary of fillers as I'd expect shrinkage or degeneration to hi-light the problem areas even more in a fairly short time. Are the modern fillers really up to the job?