Gutter Brightening & Black Streak Removal
If your gutters were washed and the black stripes are still there, nothing went wrong — house washing was never going to remove them. Tiger striping is bonded oxidation and asphalt runoff, and it takes a different chemistry and real hand work.
Three different jobs that get confused constantly
Gutter cleaning happens inside the trough: debris out, downspouts flushed. Gutter washing is the exterior face getting the same soft-wash treatment as your siding — it removes mildew, pollen film, and general grime. Gutter brightening is the third, least-known step: targeted chemistry plus soft-brush agitation to strip the oxidation and asphalt striping that washing can't touch.
Most companies quietly stop at step two and let the homeowner assume the streaks are permanent. They're not — but removing them is manual work priced by the foot, so it's sold honestly as its own line item, not smuggled into a wash quote.
- Soft-wash first, so you only pay for brightening where it's actually needed
- Section-by-section dwell and agitation — no cleaner left sitting on painted metal
- Plants and windows pre-soaked and rinsed; protecting your landscaping is part of the job
- Front-elevation-only option for budget-focused curb appeal
The finish brightening protects: crisp, uniform gutter faces that read as "well kept" from the curb.
Black streak questions, answered
Why do my gutters have black streaks that won't wash off?
Those vertical black streaks — pros call them tiger striping or zebra striping — are electrostatically bonded deposits of asphalt-shingle runoff and oxidized aluminum finish. They're not dirt, which is why a house wash or rain never removes them.
Every time rain crosses your shingles, it carries microscopic asphalt and mineral particles over the gutter lip. Combined with years of UV oxidation on the gutter's factory finish, the residue bonds to the painted face in stripes that follow the drip pattern. Notice how homes with gutter shields often lack stripes below the shielded runs — the runoff never rides over the face there.
What is gutter brightening, exactly?
Gutter brightening is a separate service from cleaning or washing: a dedicated cleaner is applied to the gutter's exterior face, allowed to dwell briefly, then agitated with a soft brush and rinsed — lifting oxidation and asphalt striping that bleach-based house washing leaves behind.
The order matters. We wash first with a standard soft-wash mix, because a surprising amount of biological grime does come off that way. What remains after the wash is the bonded striping — that's what the brightening chemistry and hand agitation are for. It is genuinely manual work: spray, dwell, scrub, rinse, and stubborn faces take two or three rounds.
How much does gutter brightening cost in Jacksonville?
Around $2 per linear foot is the honest local benchmark, reflecting the hand-scrubbing involved. Many homeowners brighten only the street-facing runs — roughly $100–$150 on a typical front elevation — rather than the whole house.
A full-perimeter brightening on a large two-story can reach several hundred dollars because every foot is worked by hand. We'll quote it both ways — front-only and full — and plenty of clients sensibly choose the front. Curb appeal lives on the street side.
Will brightening damage my gutters or plants?
Not when it's done with the right dwell times. Brightening cleaners are strong degreasers; left too long they can dull paint, which is why we work in short sections and rinse thoroughly. Landscaping below gets pre-soaked with fresh water and rinsed after, the same protocol as a soft wash.
This is the main argument against DIY brightening with random degreasers: the difference between a bright gutter and a blotchy one is timing and technique. If a corner of your gutter has already been over-stripped by a previous cleaner, we'll show you before we start.
Streaks still there after a house wash? Now you know why.
Flat quote first, work second. Most Jacksonville quotes take under ten minutes.