White build-up on Stucco

Hi everyone,
I had a homeowner contact me to wash some painted stucco walls on their house (painted render over brick).
Along the top of the garage door is a build-up of something?? caused by water dripping down from a crack along the molding above (you can see the drips there too). It had rained earlier, so I could actually see the water dripping down - it was running clear, but I have no idea what those thick white ice-cycle looking things are. They said it was ‘calcium’ and they want these removed, but I’m concerned the paint and/or render is going to come off - even if I soft-wash it and do a gentle rinse. Anyone come across anything like this before?


(water drips from a crack along the length of molding up the top, down to the area just above the garage door)


(Not sure what this build-up actually is)


(Underside - you can see the water dripping there)

either white mold or efflorescence. test spot time

I see this on the Facebook F9 page, they typically suggest dry ice blasting for the heavy calcite. Don’t know about stucco though.

Yes, good idea :+1:t3:

I’ll check it, thanks.