plating, anodizing, & finishing Q&As since 1989
"Muriatic Acid on Brick Pavers"
I have used Muriatic Acid [affil link] approximately half a quart mixed with five gallon of water to clean stains on my patio brick pavers. Pavers were fresh (never been sealed). Unfortunately, I have delayed on washing it off the pavers, now I have yellowish spots deep with in the area of the pavers that I have used the Muriatic acid. Is there any chance of removing the spots or reversing this chemical reaction from the pavers?Hugh Fayaz
- Davie, Florida, USA
"Walks, Walls, and Patio Floors"
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Hope the yellow spots are agreeable to you. They will fade over time with enough rain, however the only sure way to get rid of them is to sand blast your pavers. Your best bet is to go to Home Depot and get some new ones.
- Roswell, Georgia
The reason you are seeing yellow spots on your muriatic acid cleaned pavers is because some of the aggregates used in making the pavers are now exposed. The reason for this is that muriatic acid attacks the pigments used to color the cement that is part of the concrete mix. The pigment most widely used to color concrete is iron oxide (rust).
Muriatic acid and metals do not go well together. In fact when swimming pool interiors are are being installed, they use muriatic acid to expose the colored aggregates to give your pool a unique look. Once exposed there is really nothing you can do. You could seal them using an acrylic sealer and have the sealer tinted to a color you like. This will have to be redone about every 3 to 4 years.Geoff Bond
pavers - Brookville, Florida USA
March 7, 2008
Can you tell me why there are spots appearing on newly installed paving stones? The patio/dog run has been sealer w/Gaze and Seal and the water beads up but there are dark almost black spots appearing on many of the pavers. What could be happening?Debbie Bounds
homeowner - Vacaville, California
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