Rust on Flagstone

by Mike Siegel
(Geismar, LA - USA)



Hello Hans,

I recently installed a flagstone patio and walkway in my yard. The stone is blue/gray color and has a fast absorbtion rate. It is not acid sensitive as it does not "fizz" when muratic acid is applied (even full strength).

The problem I am having is that some of the stone has a reddish "rust" colored tint that I would like to remove. Some of the rust is somewhat loose (like dirt or sand) and can be removed with a brush and water, while other parts appear to be permanently rust stained and the stains can't be removed. Muratic acid has little effect on the rust color. This project is not grouted in - it is in a sand and limestone base with aggregate between the stones.

I would like to remove this rust color for the most part and then seal the stone to maintain a wet look that is not slippery. Some rust color enhances the look of the patio, but some stones are 100% rust red color. Do you have any ideas on how to remove the rust stains?

I attached pictures for clarity. I have scrubbed these stones with a brush and muratic acid solution up to 50% acid/water solution.



Comments for Rust on Flagstone

Click here to add your own comments

I have two possible solutions for you.
by: David

Hi Mike,

I called Prosoco, the chemical people we call for problems like yours.

The first product is called 800 stain remover. It is there most aggressive for your situation and it is a metallic stain remover. When you use it, you can't use a metal brush, like a steel brush, because it will cause the steel brush to rust and that could be where you got your problem with muratic acid. You should use a stiff non-metal brush.

The other solution is Ferrous Stain Remover.

You have to buy them through one of their distributors, so go to this page:

and type in your zip code.

You can also consult with Prosoco for the best sealer for your situation. That's where my dad buys his.

Great luck!!

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Flagstone Question.