Asphalt Shingles Rust Stain Removal

[larry4406]

Anyone with experience on removing rust stains from brick chimney and asphalt shingles?

Appears my POS chimney cap is the culprit of these stains per the chimney sweep that was here yesterday.

Surfing the net I find several common methods.

1. Many use 6-8 ounces of oxalic acid (wood bleach) per gallon of water and mix it into a pump sprayer. Wet the area with clean water, apply solution, scrub, keep wet, rinse, and then I assume repeat as necessary.

2. Some use a product called Zud Cleaner which appears to be 1-10% oxalic acid https://hpd.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=18001005

3. Others use a product called OneRestore by EaCoChem which appears to have Hydrochloric Acid as its active ingredient. https://www.eacochem.com/ProductMSDS/productMSDS_OneRestore.pdf

What does the collective wisdom of GJ recommend? I want to make sure that the cure is not worse than the symptom. Roof is relatively new (less than 10 years).

Obviously the POS cap needs to be replaced by a stainless steel unit.

 

[MarlynOC]

Oxallic acid.

 

[SALIV8]

I would just replace the chimney cap. Should go away on its own after a year or so. Imo

 

[retfr8flyr]

I've used an Oxallic acid salutation many times to clean rust stains from the asphalt roof shingles.

 

[Ole Slewfoot]

Get a can of the color matched spray paint for your shingles.

 

[Kevin54]

Spend a couple of bucks and get a couple of big bottles of CLR and let it spread out across the shingles. Let it soak for a while, then rinse with the hose. Then shitcan the chimney cap for one that won't rust or do away with it altogether.

 

[Jazz1]

I'd let Mother Nature and Father Time take care of it.

 

[larry4406]

Thanks for the responses.

I think I am leaning towards the oxalic acid method. Not sure if Home Depot or Lowes carries it. Maybe ACE hardware.

 

[nmantas]

Thanks for the responses.

I think I am leaning towards the oxalic acid method. Not sure if Home Depot or Lowes carries it. Maybe ACE hardware.

I bought some once at a smaller hardware store because the big boys didn't stock it (but can order it with free shipping to store). Also called wood bleach (but be aware there are non acid versions too).

 

[MarlynOC]

Oxallic acid at paint stores as Wood Bleach. Add a bit of Dawn Dish soap to mix to allow the spray to "adhere" to surface rather than just run off.

 

[retfr8flyr]

Order the powder online from Amazon and mix your own, that is what I do. The powder is cheap and keeps forever. I always have some on hand, as it has so many good uses.

 

[6768rogues]

Nothing but time and Mother Nature.

 

[larry4406]

Just realized I never updated this old post....

I used oxalic acid (wood bleach) in a pump sprayer and it worked very well. Wetted roof first. Local Ace hardware was only place that had it (not available at the blue and orange big box stores). Also installed a new stainless steel chimney cap.

 

[Cardboard Man]

Nice job! That turned out really well. Thanks for the update as well.