Hi John & Ray and others who may have suggestions. I was partially successful in cleaning a granite outside building wall and could use your opinions on how we might proceed. I tested a small area and the F9 Calcium and Efflorescence Remover seemed to work better then both the f9 barc & a calcium paste.

As you can see from the before and after pictures we were faced with a substantial build up of what appears to be calcium/efflorescence from several vent fans located directly next to this wall which vent onto the wall.

As we worked on the wall it was easy to see the stain even when the wall was wet but as we worked toward completion all looked clear as you can see from the pictures. After the wall dried the staining reappeared but only in certain areas. So we reattempted to apply f9 again to this area and apply substantial pressure but did not make much improvement. In fact interestingly when we used the f9 the first time the surface would foam in the areas that the build up was present, even when there was very little left until all was removed however when we applied the f9 the second time to the areas still showing build up nothing happened "no foaming occurred"

I will posted pictures above, pictures 13 & 14 are showing the wall as it looks dry, pictures 15 to 18 is the wall when wet.

Any suggestions would be greatly appreciated and I have placed a call to Craig from f9 awaiting to speak with him.

Thanks,

Gregg,

did you softwash the building before you did any F9?