How to Clean Rust from Stacked Stone Veneer
Iron oxide, or what we commonly call “rust”, is a chemical reaction that occurs when metal gets exposed to moisture and air. Its pretty common to see metal objects like a bbq grill rust out over time, but what about when you see rust on stacked stone veneer? The reason the rust can show up on stone in the first place is that many natural stones are going to have varying amounts of iron content. Left to itself, most natural stones have so little iron content they won’t rust themselves, but often times the oxidation process gets catalyzed and accelerated when the stone veneer comes in to contact with a corrosive agent, often disguised as cleaners for the stone or surfaces surrounding it, such as acids and bleach, as we well as chlorine, fertilizer, and salts.
The good news is that removing oxidation from your stacked stone application can be achieved in a number of different ways. Generally speaking to remove rust, the best course of action is to start with the mildest cleaners and then work your way up to more harsh chemicals. We normally recommend starting with a non acidic natural stone cleaner to gauge initial results. These cleaners should be available at most places where natural stone and tile are sold, or can be ordered online. Thorough scrubbing is required for these cleaners to really get down to the surface of the stone and work their magic.
If a standard natural stone cleaner doesn’t clean up the oxidation, a mid range cleaner is a product called sulflamic acid. This mild acid is used in many types of tiling applications to clean up post installation. We recommend mixing the sulflamic acid solution to the manufacturer’s recommendation and then using a stiff bristle brush to spot clean the oxidation spots on the stone. Blot any acid that remains on the stone with a cloth and then flush the area of the stone installation with lots of fresh water.
If you find yourself working on a more stubborn oxidation stain on stone veneer a stronger cleaning agent such as muriatic acid might be required. Similar the spot cleaning method described above for sulflamic acid, muriatic acid should only be applied directly to the staining and then cleaned up and flushed out with water immediately after. It’s very important to understand that the use of acids to clean stone veneer products is a precision spot by spot process, its not a broadcast application. These cleaners can also be very harmful if they come in contact with skin, so proper precautions should be taken including proper eye safety and adequate ventilation.
The final step in cleaning oxidation stains off stacked stone veneer is to always go back and seal the stone stacked stone with a quality water based natural stone sealer. The sealer might not necessarily prevent the oxidation from returning, but it will definitely decrease the rate at which oxidation occurs and also make cleaning future oxidation stains much easier.
Speaking of prevention, the best way to handle oxidation staining on stacked stone veneer is to understand why it’s happening in the first place and take steps to prevent it. For example, if you know that once a year you’re handyman pressures washes your concrete patio with a diluted bleach solution, a good idea would be to cover any stacked stone in that area, or use a detergent cleaner with the pressure wash instead. Or if you know your sprinkler water has really high iron content and causes the stone veneer around your house to rust and stain, adjusting the irrigation to avoid over spray onto the stone is an easy fix that saves a lot of hassle down the line.
We hope you enjoyed this brief look at how to clean rust from stacked stone veneer applications. With a decade and half selling stacked stone veneer products and millions of square feet sold all over the world Norstone has “seen it all” when it comes to rust problems with stacked stone installations and we’re here to help answer any questions you have with your Norstone application.