Published on November 3rd, 2015 | by Henri0
Rust stains on deck
Q. I have a couple of long and narrow rust marks on my deck, which is made of AZEK composite decking.
I had large flower pots that were resting on 2 painted metal bars so that water could drain from the pots, which I was using to grow tomatoes.
The stains are clearly rust colored and extend the length of the two round
bars (3 feet each bar. The width of the bar is about 1/2″ in diameter).
Do you have any suggestions for removing the rust spots?
A. Azek composite decking receives mixed reviews regarding staining. Some claim that this decking stains very easily, and is hard to clean, while others have reported the opposite. Much depends on the cause of the staining.
Rust stains are always difficult to remove if they have penetrated deeply into the material.
Hopefully, the rust stains have not penetrated the deck boards too deeply, which may make it impossible to remove them.
Obviously, water reached raw metal in spite of the fact that the ferrous metal bars were painted.
Try to wash the rust stains off with a solution made of one part bleach to three-parts water. Use a soft-bristle brush in order not to scratch the deck finish. If this does not work well enough, increase the portion of bleach to water.
You could also try using Zud, which contains oxalic acid, a corrosive chemical, but one very active in removing rust stains. Be sure to read and follow the precautionary directions on the Zud container.by