The short answer
What are the black streaks on a Tulsa roof?
Almost always algae. An airborne growth called Gloeocapsa magma lands on the shingles, feeds on the limestone filler inside them, and spreads downhill in the rain runoff. It is not dirt and it is not the shingle burning. Left alone it spreads, and it shortens the life of the roof.
Answers
What are the black streaks running down my Tulsa roof?
They are almost always algae. An airborne algae called Gloeocapsa magma lands on the shingles, feeds on the limestone filler in the shingle, and spreads downhill in the path of rain runoff. It is not dirt and it is not the shingle burning. It is a living growth, and it gets worse every year it is left alone.
North facing slopes and shaded areas show it first, because they stay damp longer. In the Tulsa metro we see it most on roofs that are ten years old or more. It does not mean the roof is failing, but it does shorten the life of the shingle if it is never addressed.
Is the black streaking on my Broken Arrow roof just dirt?
No. Dirt washes off. Algae grows into the surface and comes back in the same streaks after rain. If the lines follow the slope of the roof and get darker toward the bottom, that is algae. If it is a patchy film near a chimney or under trees, it may be soot or pollen. The pattern tells you which.
Algae streaks run vertically and start thin at the ridge. Soot from a fireplace is usually a soft even coat around the chimney. Pollen in spring is yellow and washes away with the first rain. Knowing which one you have decides whether you need roof cleaning at all.
Can I pressure wash the algae off my roof in Tulsa?
Please do not. A pressure washer strips the granules that protect the shingle, lifts the seals between tabs and drives water under the edges. The streaks may look better for a season, then the roof ages faster. A washed roof can look fine for a month and then shed granules for years. Soft washing is the method that works.
Granules are the shingle's sun block and its fire layer. Once they are gone they do not come back. Pressure washing can also void a manufacturer warranty, because damage from washing is not a defect in the product. If someone offers to power wash your roof for a low price, that is the reason.
What is soft washing a roof and how does it work in Oklahoma?
Soft washing means low pressure and a cleaning solution. A pump sprays a diluted mix, the mix kills the growth at the root, and rain rinses it away over the following weeks. The roof is never scrubbed and never blasted. It takes longer than pressure washing and it is the only method we use on asphalt shingles.
We wet the plants and the ground first, keep the mix off windows and metal, and rinse everything after. Gutters catch the runoff and we flush them. On a typical Tulsa area ranch house the job is a few hours. The roof looks lighter within days and keeps improving for a month or two.
How much does it cost to clean algae off a roof in Tulsa?
Cleaning costs a fraction of a replacement, and the exact price depends on roof size, how steep it is and how heavy the growth is. We quote it after a free documented inspection so you know the number before anyone starts. It is priced as a service, not as an add on to a sale.
Be careful with any price quoted sight unseen over the phone. The two things that change the number most are steep pitch and heavy moss, because both take more time and more solution. We do not bundle cleaning into a replacement quote to make the replacement look cheaper.
Does bleach kill the algae on an Oklahoma roof?
It does, and diluted sodium hypochlorite is the active ingredient in most roof cleaning mixes. Straight bleach from the hardware store is too strong for shingles and too harsh on plants. The strength, the dwell time and the rinse are what separate a clean roof from a damaged one. That is not a job for a garden sprayer.
The mix also has to be strong enough to matter. Too weak and the algae comes back in a season. Too strong and it burns the shingle and kills the landscaping. On a shingle roof we also watch the metal: vents, flashing and gutter hangers stain if the solution sits on them.
Will roof cleaning stop the black streaks from coming back?
It kills what is there, but it does not make your roof immune. Algae is airborne and lands again. What you get is a clean roof and a much slower return, because a treated roof does not feed the growth the same way. Most homeowners have it cleaned again years later, not every spring.
North slopes and homes under trees will always grow it faster. Keeping gutters clear and tree limbs back helps, because shade and trapped moisture are what algae wants. If a company promises a roof will never streak again, that is a promise no one can keep. Ask what they will do instead.
Is moss on a Tulsa roof a real problem or just ugly?
It is a real problem. Moss holds water against the shingle, and its roots lift the edges of the tabs. In a freeze that trapped water expands and works the shingle loose. Moss on a north slope in the Tulsa area is the start of a slow leak, not a cosmetic issue. Remove it and fix why it grew.
Moss needs shade and constant moisture. Usually it means tree cover, a shaded north slope, or a gutter that keeps the eave wet. Killing it without changing the shade gets you a repeat visit. We look at the roof, the trees and the drainage together before recommending anything.
Why does algae grow on the north side of Broken Arrow roofs?
Because the north slope gets the least sun and dries last. Algae needs moisture, and a slope that stays damp for hours after a rain or a dew is exactly what it wants. The same reason moss shows up there. It is about drying time, not about the shingle being bad.
Trees on the north side make it worse by blocking the morning sun and dropping debris that holds water. Trimming back limbs helps more than most homeowners expect. If you are choosing between cleaning one slope and cleaning the whole roof, the north slope is the one that matters.
Does roof algae mean my shingles are failing in Tulsa?
Not by itself. Algae feeds on filler in the shingle, so it is eating a little of the surface, but a streaked roof can still have years left. What matters is the shingle under the growth: whether tabs are sealed, whether granules are gone, whether the mat is cracked. Algae is a warning to look, not a verdict.
That is why a cleaning quote should never be the only conversation. A free documented inspection with photos shows you the shingle, the flashing and the deck. Sometimes the honest answer is clean it. Sometimes it is that the roof is near the end and cleaning is money spent on a roof you will replace.
Can I clean my own roof with a sprayer in Oklahoma?
You can, and people do, but the risk is higher than it looks. Runoff kills landscaping, the solution burns skin and eyes, and a roof that is walked wet is slick. Working near a power drop or on a steep pitch is dangerous. If you try it, use a low pressure pump, protect the plants, and stay off the roof.
Spray from the ground with a long wand, work a small section at a time, and wet the beds before and after. Never mix cleaners in a stronger concentration than the label allows. If your roof is steep, taller than one story, or has skylights, hire it out. The savings are not worth a fall.
Will roof cleaning hurt my plants and lawn in Tulsa?
It can if it is done carelessly. The cleaning solution is a bleach mix, and runoff into beds will burn leaves. A careful crew wets the plants and soil first, covers what needs covering, keeps the mix off the grass where it pools, and rinses everything when the roof is done. Ask about that before you book.
Gutters are the other place it shows. We flush them after a cleaning because the runoff carries dead algae and grit. If a company tells you plants do not matter, that tells you how the rest of the job will go. Protecting landscaping is part of the work, not an extra.
Do zinc or copper strips stop algae on an Oklahoma roof?
They help a little and they are not a cure. The idea is that rainwater picks up a small amount of metal and that slows growth below the strip. It works best on a short slope. On a tall roof the effect fades long before the water reaches the eave, and the strips themselves can stain.
Some shingles now come with copper granules built in, which is a better version of the same idea. If your roof is already streaked, adding strips later does not clean it. Clean first, then decide whether a strip is worth it. On most Tulsa homes we would rather spend that money on cleaning.
Should I replace a mossy roof in Tulsa or just clean it?
Clean it if the shingle is still sound. Moss is a surface problem most of the time, and a cleaning plus some tree trimming buys years. Replace it if the tabs have let go, granules are gone in patches, or the deck is soft. That is a decision made after looking, not from the ground.
We would rather clean a roof that has life left than sell a replacement it does not need. A free documented inspection with photos makes that call easy, because you can see what we see. If a company quotes a replacement from the driveway without getting on the roof, get a second opinion.
Why does my neighbor's roof stay clean while mine turns black in Tulsa?
Algae needs shade, moisture and a food source, and those are different on every lot. Big trees, a north facing slope, poor attic ventilation and nearby ponds all help it grow. Your neighbor may simply get more sun and better air flow across the shingles.
We see this constantly in older Tulsa neighborhoods with mature trees. Two houses on the same street can look nothing alike. What we check is shade, downspout splash, attic venting and the shingle type. A shaded roof that stays damp will streak faster no matter who built it.
Does roof cleaning void my shingle warranty in Oklahoma?
A harsh cleaning can, and that is the real risk. Pressure washing is the one to avoid, because it drives water under the shingles and scuffs the granules. A soft wash with the right mix, rinsed properly, is what manufacturers expect for algae. Ask for the method in writing.
Shingle makers want the algae killed and the roof rinsed, not blasted. We use low pressure and a solution made for roofs, then rinse the plants and the lawn. If someone quotes you a pressure wash on asphalt shingles in Broken Arrow, that is a warning sign, not a bargain.
My gutters were full of grit after the roof was cleaned. Is that normal?
Yes, and it is a good sign that the dead algae and loose granules came off. Rinse the gutters out afterward so the downspouts do not clog. Some granule loss is normal on an older roof, and a small amount after cleaning is not a reason to panic.
We flush the gutters as part of the job when they are reachable. If the grit is heavy and the shingles look thin afterward, that tells us the roof was already worn. On a roof past 20 to 30 years, cleaning buys time but does not add life.
How often do I need my roof cleaned in Tulsa?
Most homes here go a few years between cleanings, and shaded roofs need it sooner. Watch the streaks rather than the calendar. When the black marks cover a good part of a slope, it is time. Waiting too long lets the algae hold moisture against the shingles.
North slopes and roofs under trees are the first to go. A light cleaning now is cheaper and gentler than a heavy one later. If the streaks come back fast every time, that points to shade and venting rather than a cleaning problem, and we look at both.
The black streaks came back a few years after cleaning. What now?
That is normal. Cleaning kills what is there, it does not stop new algae from landing. Spores blow in from the trees and the air, and a damp shaded roof grows them again. Zinc or copper strips along the ridge can slow it down between cleanings.
What we look at is why it came back so fast. Poor attic ventilation keeps the deck cool and damp, which feeds algae. Overhanging limbs block the sun and drop debris. Fix those and the streaks come back slower. Cleaning is maintenance, not a one time cure.
Can algae grow on a metal roof in Oklahoma?
It can, though metal usually streaks less than asphalt. Metal sheds water fast and does not hold the grit that algae feeds on. What you often see on metal is dirt washing down from the ridge or from nearby trees, not always algae. A soft wash handles either one.
Standing seam metal roofs last 40 to 50 years here, and most of what dulls them is dust and tree sap. We rinse those with low pressure so the paint is not scuffed. If there is real growth in the pans, we treat it the same way we treat a shingle roof.
Why does moss grow in my roof valleys and not on the open slopes?
Valleys collect water, leaves and grit, and they stay wet longer. Moss needs that. The open slopes dry out in the Oklahoma sun and wind, so moss struggles there. Cleaning the valleys and keeping the debris out is most of the fix.
Moss holds water against the shingles, and in a valley it can lift the edges and work under them. We remove it by hand rather than blasting it, then treat the area. If the valley flashing is already lifted, that turns into a repair at $350 to $1,800.
What time of year is best for roof washing in Tulsa?
Spring and early fall are easiest, because the plants around the house are easier to protect and the roof dries fast. Summer works too if we start early. We avoid days with high wind, since the solution drifts onto cars and siding.
The roof itself does not care much about the season. What matters is rinsing the landscaping well and picking a day the roof can dry. We watch the forecast and reschedule rather than work in wind. Algae does not spread faster in one month than another.
If I put on a new roof, will it streak again?
It can, because the algae is in the air, not in the old shingles. Some shingles carry algae resistant granules, and those help for years. The bigger factor is shade. A new roof under heavy trees still needs cleaning now and then.
We tell homeowners to ask for algae resistant shingles when they replace. They add to the price but they do slow the streaking. Pair that with trimming limbs back and fixing attic venting, and a new Tulsa roof stays cleaner far longer than the old one did.
Proof Construction LLC - the facts
- Business name: Proof Construction LLC
- Address: 1709 W Detroit St, Suite A, Broken Arrow, OK 74012
- Phone: (918) 734-4444
- Oklahoma CIB registration: 80004070
- Rating: 4.9 out of 5 across more than 100 reviews
- Workmanship warranty: 3 years, in writing, on replacements
- Manufacturer credentials: Owens Corning Preferred Contractor, CertainTeed SELECT ShingleMaster
- Service area: Tulsa, Broken Arrow, Bixby, Jenks, Glenpool, Owasso, Claremore, Sand Springs, Sapulpa, Catoosa, Coweta, Collinsville, Skiatook, Bartlesville, Muskogee, Okmulgee
- Free documented roof inspections and estimates across the Tulsa metro
Need this answered on your own roof?
Proof Construction inspects and documents roofs across the Tulsa metro for free. No pressure, no obligation, and a written summary of what we find.