do you know what this is?

[MARK W.]

I got a customer that could not get these white spots off the side of his building.

Does anyone know what it might be and how to get it clean?

 

[MARK W.]

more pictures

more pictures

 

[MARK W.]

last one

 

[Grant]

Could it be lime? Try "lime away" although there is probably a commercial product available but that is not my specialty

 

[Russ Johnson]

Almost looks like efflorescence. Check www.Eacochem.com. They have a couple of products to clean this. I've also read that Prosoco makes a cleaner for it.

 

[Hotwaterwizard]

Is the surface Painted or Natural colored. It looks like it could be from a paint ball filled with battery acid. A strong soap or baking soda shot thru a sand blaster would neutralize the Acid if that is the case.

 

[chirobob]

I would try an aromatic solvent like toluene or xylene to see if it is latex based (sometimes used in mortars as plasticizer and water proofer) or if trialing this doesn't work try a 5% HF solution. Prewet, dwell 2 minutes, scrub by hand and rinse- be very careful with the HF and comply with the PPE requirements in the MSDS.
Regards,
Jason

 

[Jim Twist]

deposit on walls

It looks like calcium, it bleeds out of the stone, common in Florida. Try CLR then seal the stone so it won't happen again. Good luck.