How to Get Rid of Rust Stains On a Shingle Roof

Asphalt shingles are susceptible to stains, whether from algae that forms from moisture buildup or due to rust from corroded soil pipes and nails. Your first thought may be to power wash the roof or scrub the stained shingles with a stiff brush. These cleaning procedures will only damage the roof further because the force of the water or brush removes the granules that reflect sunlight and exposes the face of the shingle to the elements.

Rubber gloves
Oxalic acid
5-gallon bucket
Spray applicator
Ladder
Safety glasses
Garden hose
Soft scrub brush

Instructions

- 1
  Wear rubber gloves to mix the oxalic acid crystals and water in a bucket according to package directions. Generally, the recommended mixture is 1 lb. of crystals to 2 gallons of water. For light stains, you may use up to 5 gallons of water.
- 2
  Pour the mixture into the sprayer. Apply the oxalic acid mixture to the rust stain. Allow the mixture to thoroughly saturate the stained shingles. Oxalic acid reacts with the iron stains like a bleach. The stain will lighten as the acid works.
- 3
  Rinse the shingles with clear water to remove the oxalic acid mixture. Check the roof to determine how much of the stain remains. Apply a second application of the oxalic acid mixture if any stains remain. Rinse with clear water.
- 4
  Scrub the shingles gently with the acid mixture if stubborn stains remain. Only use the brush if it is absolutely necessary. Avoid harsh scrubbing techniques to keep shingle damage to a minimum.
- 5
  Rinse the roof completely and also clean the gutters. Spray off any landscape plants or areas under the roof that may have been exposed to the oxalic acid during cleaning.

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