Correcting damage around window reveals

[JamieB3009]

Hello,

I would like some advice on the best recommended method to create a lasting repair around window reveals and also windowsills that will not keep reappearing shortly after repair is done. The damage is as per the attached photos. I have tried regjlar filler but it just keeps re cracking shortly afterwards. Any recommendations.

Thanks

 

[Wayners]

Dig out mastic.
Sealing helps as plasterboard gypsum it's very dry. Filler can struggle to stick properly.
If you have any wood glue which is PVA, you can water down 50/50 or more as it's not critical, and seal the exposed gypsum.
Two coats as and let it dry for 4+ hours.
2kg box of toupret is the best stuff IMO but fill in two goes.
Soon as the first mix sets in around an hour hit it again with another mix. Smooth off.
When dry sand using 120 grade on a block of wood so it's flat.
Paint first coat.
Thin run of caulk around window as that will stick well to paint.
Second coat of paint to finish..
If you have movement around window causing a crack you need to fit a small trim, but don't worry about that now..