Paint peeling on external wall

Harcrid

Any ideas what may be causing the below?







To give the full background, we bought the house over 10 years ago (new build) and after a few years the paint started to peel in this same patch, with what appeared to be a green type of mold behind it. We powerwashed the paint and mold off and repainted it but the same thing occurred a few years later.

So in July 2019 we had the whole house powerwashed and the new painter applied some of sealer or treatment before repainting ( I cant remember what product he used) which he said would take care of it. No sign of any issues until the cold snap last week which seems to have made all this paint peel almost overnight which would lead me to believe there is moisture present which froze and caused the paint to peel.

Interested to hear if anyone can shed some light on what may be the cause?

Bullocks

I'd say possibly water getting in around the window cill and into the plaster. Is there a crack off the corner of the cill aswell?
That would definitely soak in a bit.

listermint

Usually this means the subsurface is wet , either not fully drying out or is getting more moisture from a source either external or internal.

E.g rain or leaky pipe. Presume it's just a sand cement render underneath ?

Harcrid

Just standard sand render i believe. The only pipework in the area would be an internal radiator beneath the window that you see in the picture but I dont see any evidence of it leaking. That side of the house does take the brunt of the bad weather but its always the same patch it returns.

listermint

I'd recheck the radiator and floor. But it's unlikely it's bridged the cavity .

Most likely there's a crack in the render above or around that area that's letting rain in behind storing it and causing a wet damp surface which the paint lifts away from .

May have to get the paint taken back again in dryer weather . Review and repair the render . Let it dry out in sun and repaint.

Harcrid

Thanks listermint and Bullocks for the feedback. Kind of confirms my thoughts. Appreciate it.