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Q: Why are there dark streaks on my roof?

A: Dark streaks on your roof are caused by an algae species called gloeocapsa magma. It is not generally harmful, though it can be a sign of excessive moisture and even cause granule loss over time. You can lighten the dark streaks on your roof using a solution of bleach and water, or prevent it by choosing algae and streak-resistant shingles.

Roof with dark streaks on the shingles

Q: How can I tell when I need a new roof?

A: Major issues will be readily visible. The biggest red flag is active leaking. After a storm, inspect your attic for damp spots or discoloration around your chimney and roof vents.

Also look for bald spots from excessive granule loss; missing, curled or cracked shingles; and moss growth. These can lead to leaks and expensive repairs if not addressed. These are the most immediate warnings, but you can read about more signs that your roof needs to be replaced here.

Exterior of a home focused on the roof

ROOF SMARTER™

Replacing a roof is a process. When you invest so much time in a project, you shouldn’t like the results, you should love them. In addition to helping pick just the right color, we can help you understand the entire reroofing project. Our Roofing 101 Guide will help you know the warning signs that you need a new roof and take you step by step through the process, from design inspiration to product selection to hiring a contractor.