Rust stain on your composite deck is so disheartening. Your beautiful deck ruined with a ring from the propane tank. Don’t despair, rust stains are nasty on composite decking, but they can be removed.
Some everyday household products that will remove rust stains from composite decking are Dawn Ultra, vinegar, lemon juice, toilet bowl cleaner, Oxyclean, and WD 40. Convenient wipes for removing rust stains are Magic Eraser® and DeckMAX® PVC Revitalizing Wipes.
Before using any cleaning products, always check in a non-conspicuous part of the deck before using it. To start, there are a couple of cleaning products you should never use on a composite deck. Never use chlorine bleach or acetone on composite decking as it will damage the decking.
Composite decking is both a propriety and an evolving product. Making it a good idea to check with individual manufacturers’ recommendations before damaging your deck. With some decking manufacturers using different materials in their composite. The good news is most of the newer composite decking is designed with a polymer cap. Meaning if its safe for polymer (plastic), it should be safe for your decking. As the cap both seals and protects the core.
If the composite decking is not capped, you are dealing with two material now, wood and plastic. Making removing the rust a little trickier as it needs to work for both wood and plastic and, at the same time. Able to remove the stain from the wood fibres as they will absorb more than the plastic material.
Let’s go through our list of rust removing cleaners, explaining how they work and how to use them on your deck. Starting with more general and gentler rust deck cleaner, progressing to stronger cleaners for the nastier rust stains.
General Composite Decking Cleaner
Same as washing your dishes or your kitchen floor. Assuming you have a vinyl kitchen floor but similar to tile. Mix a little in a bucket of water and clean your decking with a cloth or medium plastic bristle deck brush. TimberTech warns against using natural bristle brushes as they can dull the surface of the decking.
Always rinse your decking clean after as to remove all soapy residue from your deck. Soap residue is unsightly and can be slippery on your deck.
If you are cleaning your entire deck, most manufacturers have their own deck cleaning products specifically designed for cleaning composite decking. You can use theirs, or you can pick up a general composite deck cleaner. Check their warranties as some will only warranty their decking if cleaned with their cleaner. As always, check that it is safe on your decking before using it.
Moving down the list to stronger rust removing products.
Removing Rust Stains with Vinegar or Lemon Juice from Composite Decking
Both Vinegar and Lemon Juice are acidic and will dissolve iron oxidation, rust. Lemon is nice in that it has a citric smell, unlike vinegar. If you are like my wife, who is repulsed by the smell of vinegar. Stronger than soap in dissolving rust stains. As soap is a base, absorbing the material but acid dissolves it. A stubborn rust stain will be removed better with acid than soap. Here are three ways to use Vinegar or Lemon Juice on rust stains
- Start by mixing a 50-50 solution of water and vinegar or lemon juice. Spray on the rust stain. Let sit for 10 minutes and then wipe clean. Repeat till the rust stain is removed from the decking. Rinse clean to prevent residue from forming on the deck.
- For a darker or stubborn rust stain, use full-strength vinegar or lemon juice. Pour on the rust stain and let stand on your deck for 10 minutes and then rinse clean. Thoroughly rinse the decking to prevent vinegar or juice residue.
- For a really hard to remove rust stain, mix vinegar or lemon juice with borax (another acid) into a paste, like toothpaste. Apply to the stain and let it sit a few hours or overnight. Then rub the paste off with a scrubbing pad. Careful not to use a pad that will damage the decking. Again, once removing the rust rinse off all the paste and residue from the decking.
Coke removes rust stains but not recommended on composite decking
I just want to mention coke as it is legendary for cleaning stains. From blood to rust, coke is renowned for cleaning stains.
Just the other week, I was talking with my neighbour as she was doing some auto body repair, and she recommended using coke to remove rust from my van. It is powerful and amazing, the phosphoric acid does remove rust, but the sugar leaves a sticky residue on your deck. Using coke to remove rust is just exchanging one stain for another on your deck. In a bind, maybe but not recommended.
Toilet bowl cleaner to remove nasty rust stains from composite decking
I was surprised when I first heard this one. I was like what? Toilet bowl cleaner is for toilets, for cleaning…you know what off. But looking on the back of the toilet bowl cleaner and right on the bottle is says “rust removal.” Well, I’ll be, toilet bowl cleaner removes rust stains.
Toilet bowl cleaner contains Hydrobromic Acid, another powerful cleaner. But a word of caution, over 20% hydrobromic acid will damage PVC, plastic. Toilet bowl cleaner is less than 20%, but we are flirting with danger as it can damage the decking.
Apply on the rust stain and scrub with a medium plastic bristle deck brush. You may need to let it sit for five minutes to help to remove the rust. Again, no natural bristles as they can damage the decking. Work it back and forth in the direction of the decking with the brush till the rust is dissolved. Rinse and clean off the decking of all the toilet bowl cleaner. Again, a powerful acid, if left on the deck it can damage the decking.
Oxiclean for Cleaning Rust Stains on Composite Decking
From the kitchen (Dawn) to the laundry room to remove rust from composite decking. Works well for making your whites, whiter and removing rust from your deck. Instead of chlorine bleach that will damage composite decking, OxiClean is safer using oxygen ions to clean. As an additional advantage, OxiClean will not harm plants around your deck as bleach will.
Dampen the decking first before applying OxiClean. Then scrub it with a medium plastic bristle brush working the rust off the composite. It shouldn’t take much with capped composite decking as the cap prevents the rust from being absorbed by the decking. And one more time, thoroughly rinse off the decking. Yes, whatever you clean a deck with must be clean off to prevent damage or residue.
WD-40 will remove rust stains from Capped Composite Decking
It loosens rusty bolts and cleans rust mark of decking. I love WD-40 and always keep an extra bottle around just in case something needs to be loosened. It’s also good for removing rust stains from capped composite decking. Only capped composite because the chemicals in WD-40 can stain the wood fibres if not protected by the polymer cap.
Similar to nut removal, spray on and let sit for a few minutes, then wipe off with a paper towel or an old rag. Something that can be thrown away after cleaning of the WD-40. Care must be taken to wipe off all of the WD-40. Otherwise, it will collect dust on the decking. Exchanging one mess for another.
Wipe clean light rust marks on composite decking
This is more for when some rust powder falls on the decking after moving the barbeque or something similar. Not really a stain but a rust mess none the less.
Trex recommends using original or extra power magic eraser. Can’t explain how, its magic. But the little foam block is fantastic at picking up a mess without damaging what’s below it. On newly painted walls, which should never be wiped for 28 days, I have used a magic eraser to gently and safely wipe off the dust from the fresh paint. It’s that good and also works for removing light rust stains from decking.
Fiberon recommends a wipe designed explicitly for decking care. DeckMAX® PVC cleaner comes in a handy container full of disposable wipes to clean off rust from your deck and any light mess for that matter.
Conclusion of removing rust stains from Composite decking
There you have it seven ways to remove rust stains from composite decking, using everyday household products. You’re in good shape, your deck can be returned to its former glory, and you can sit back and enjoy your deck.
PS exchange that rusty old propane tank for a new one without rust. You don’t want to do this again. Or even better put a grill mat under your barbeque, protect your decking from rust and grease.