Roof Cleaning in St. Louis: Stop Algae Stains Before They Damage Your Shingles

If you see black streaks sliding down your shingles, you are not alone. Those stains are often living algae, and the safest way to deal with them is a professional roof cleaning service that uses the right solutions and low pressure to protect your roof.

Why Black Streaks On St. Louis Roofs Matter

Across St. Louis, from Tower Grove to Webster Groves, our mix of shade trees, summer humidity, and seasonal rains creates the perfect place for roof algae to thrive. The main culprit is a blue-green algae that many homeowners recognize as those dark streaks that refuse to rinse away.

Left alone, algae and moss hold moisture on the shingle surface. Over time, that trapped moisture can speed up wear, lift edges, and make your roof look older than it is. Clean shingles reflect heat better, too, so a clean roof can help your attic stay cooler during our hot July afternoons.

Black streaks are algae, not dirt, so simple rinsing or a high-pressure blast will not fix the problem and can make it worse.

What Actually Causes Roof Algae And Moss In Our Area

Algae feed on the limestone filler inside many asphalt shingles. When you add shaded roof planes under big oak and maple canopies in places like Kirkwood, University City, and South City, the surface stays damp longer, and growth speeds up. After a few seasons of pollen and leaves, the streaks become easy to see from the curb.

Moss and lichen can show up too, especially on the north side of the roof where the sun is weakest. These growths anchor into the shingle surface and hold even more moisture, which can lead to granule loss around the affected spots. That is why treating growth early is smarter than waiting until clumps are visible from the street.

Soft Washing Vs. Pressure: The Right Way To Clean Shingles

There is a safe way to clean a roof and a risky way. The risky way is high pressure, which can tear off protective granules and shorten the life of your shingles. The safe way is called soft washing, which uses carefully mixed cleaners and very low pressure to loosen and rinse away the stains while protecting the roof system.

Soft washing uses low pressure to protect the shingle surface while the cleaning solution does the real work. A trained technician applies the solution, allows proper dwell time, and then performs a gentle rinse. Plants and gutters are protected, and runoff is managed so your landscaping is safe.

How Professional Roof Cleaning Protects Your Home

A clean, streak‑free roof does more than look good. It also supports the health of your home by keeping water flowing and heat reflecting the way the roof was designed.

• Protects shingle life by removing growth that traps moisture on the surface.
• Improves curb appeal for homes in neighborhoods like Dogtown, The Hill, and Clayton.
• Helps gutters drain by reducing granular debris and organic buildup near the edges.
• Supports attic comfort because cleaner shingles reflect sunlight more consistently.

Many buyers in St. Louis, MO, look at the roof first when viewing a home. If you plan to sell in the next year or two, a clean roof can set the tone for the rest of your property before the showing even starts.

When To Schedule Roof Cleaning In St. Louis

Our climate gives you several good windows to book a service. Spring and fall are homeowner favorites because temperatures are mild and weather patterns are steadier. Summer works too, but crews may start earlier in the day when it is cooler. Winter cleanings are possible during above-freezing stretches, though ice and snow will delay work for safety.

Think about what surrounds your home as you plan. Heavy tree cover in places like Glendale and Maplewood means more shade and leaf debris, which often calls for more frequent cleaning. Homes with wide southern exposure in Chesterfield or Creve Coeur may go longer between treatments.

Roof Types Around St. Louis And How They Are Cleaned

Asphalt Shingles

Asphalt shingles are common across the metro, and they respond best to soft washing. The process keeps granules in place while the cleaner targets the organic growth causing stains.

Clay, Concrete, And Slate

Several older homes closer to the Central West End or Lafayette Square feature tile or slate. These materials need careful handling and low pressure, along with measured rinsing, so water does not push up under the tiles.

Metal Roofs

Metal panels collect pollen and dirt that dull the finish. A gentle application and rinse can clean them up without streaking or spotting.

Never let anyone use high pressure on asphalt shingles or brittle tile; it can strip the surface and create leaks you will not see until the next heavy rain.

What To Expect When You Hire Exterior Cleaning Solutions STL LLC

We start with a simple conversation and a quick look at your roof from the ground or from safe vantage points. You will get a clear explanation of what we will clean, how we will protect your plants and gutters, and how long it should take. On service day, our team sets up ground covers near downspouts, moves lightweight items, and confirms water access.

The soft wash solution is applied evenly across stained areas first, then across the rest of the roof for a uniform finish. After the dwell time, we rinse with low pressure and check valleys, skylights, and flashing. Before we leave, we tidy up the work area and walk you through the results.

If you want a single source for exterior care over time, our pressure washing company can also take care of siding, patios, and walkways on a future visit so the rest of your home matches your clean, bright roof.

Local Signs It Is Time To Call A Pro

• Dark, shadow-like streaks that do not lift after a heavy rain.
• Green clumps or fuzzy patches along shaded eaves or under overhanging limbs.
• Granules are collecting in your gutters after storms or yard work.
• Water is running over the front of the gutters because debris is accumulating near the roof edges.
• New stains reappear on the same roof plane each spring.

If you notice any of these in your home in St. Louis, MO, it is better to act now. Algae spreads over time, and dealing with it early keeps your roof looking fresh and doing its job.

Preparing Your Property For A Safe, Effective Cleaning

There is not much you need to do before we arrive. We suggest closing windows, parking cars away from downspouts, and letting family members know we will be on site. If you have delicate plants near splash zones, we will hydrate and cover them before we start, then rinse when we are done.

You can expect some light runoff in the gutters and at the base of downspouts as we flush the system. That is normal. We take care to control flow and protect landscaping as part of the process.

How Often Should St. Louis Roofs Be Cleaned

Most homes in our area do well with a cleaning every 2 to 4 years, depending on shade, roof pitch, and surrounding trees. Heavily shaded or north-facing homes may benefit from shorter intervals. Homes with more sun and less tree cover can often go longer. During your visit, we will share what we see and suggest a practical timeline for your property.

Common Myths About Roof Washing

• “Rain Will Wash It Off”
  • Algae bonds to the shingle surface and will not rinse away. A controlled soft wash is the safe and effective approach.
    
    
• “Higher Pressure Cleans Faster”
  • High pressure can drive water under shingles, strip granules, and leave permanent marks. A slower, low-pressure method preserves the roof and gives better long-term results.
    
    
• “Those Stains Are Only Cosmetic”
  • Algae hold moisture and collect dirt. Over time, that moisture can add stress around edges and fasteners. Treating stains early is simple prevention.

Ready For A Cleaner, Longer-Lasting Roof

If your shingles are showing streaks or green growth, scheduling a gentle cleaning now can save time later. Our team will assess your roof, protect your landscaping, and deliver an even, streak‑free finish that boosts curb appeal right away.

Want your roof to look new again and stay protected through the St. Louis seasons? Call Exterior Cleaning Solutions STL LLC at 314-406-3595 to book a visit.