The streaking is algae and is cosmetic. Moss is not – it holds water against the shingle. Zinc or copper strips at the ridge suppress both and are a modest addition during other work.

This is most common in homes built roughly 1980 to 2000. The polybutylene and aluminum-wiring window, 150 amp panels, R-22 systems and first-cycle architectural shingle.

You can handle this one yourself. No call needed.

Related

• Two or three layers of shingle already on the roof
• Plank decking with gaps between the boards
• Rust streaks below the chimney flashing
• Wood shingle under the asphalt
• No ridge vent and no soffit intake
• Valley metal rusted or missing
• Masonry chimney needs work
• Sagging visible along the ridge line

Back to Roofing.

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Written by Jaylan Jones. I Like To Exterior Services earns a referral fee when a call connects to a contractor. See our business-model disclosure.