Does anyone know what this may be on this brick? I believe it is calcium build up but not to sure. And what chemical would be best to use? Thank you guys
Most likely efflorescence, but it could be calcium or mortar residue. How long has it been there? What happens if you rub it with a stiff nylon brush or your finger? If you wet a small test spot with plain water does it disappear and then return or does it stay visible? Was it ever cleaned with a acid-based cleaner?
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efflorescence, almost certainly caused by moisture leaching from the planter soil through the masonry and pulling salts out with it. You can clean it with hydrochloric acid that you make yourself (dilute pool muriatic from hardware store) or order a manufacturer created masonry cleaner (prosoco makes one and another good one is NMD80, both of which are buffered acids that will do a better job than just diluted muriatic) but set expectations of the homeowner that the efflo will return if the situation isn’t fixed that’s creating it.
You might not even need a cleaner if you’re able to break it up with a brush and then pressure wash the residue off with moderate pressure around 500-800 PSI. I figured you try that first though.
Perfect! I appreciate it guys. The residue does seem chalky when rubbed and in some spots. This is for a friend who wants it done. So I will be doing a test spot to see if it comes out with scrubbing before trying chemical
