Leaving black streaks and green moss untreated does severe, permanent damage to your home:
Shingle Eating: The black streaks are Gloeocapsa Magma, an algae that actively feeds on the limestone filler inside your shingles, making them brittle.
Water Traps: Moss acts like a sponge, trapping constant moisture against your roof deck. This rots the wood beneath and causes hidden structural leaks.
Shingle Lifting: Moss roots wedge underneath shingles, lifting them up and exposing your home to severe wind damage and water intrusion.
Skyrocketing Energy Bills: Dark, algae-covered roofs absorb massive amounts of heat, forcing your air conditioner to work twice as hard.
When we clean your roof, you might hear us use this industry phrase. Here is exactly what that means for your home:
"If it's black, it's back": Living, destructive algae on your roof appears as dark black streaks. If you see black, it means the infestation has returned (or was never treated properly at the roots) and is actively eating your shingles.
"If it's brown, it'll wash down": Once our Sodium Hypochlorite solution hits moss and lichen, it instantly kills them, turning them a dead, brittle brown color. This brown color is proof that the organism is dead. Because its root system has completely detached from your shingles, the dead moss safely loosens and washes away down the gutters during the next few rainstorms.
We never use high-pressure pressure washers on a roof. High pressure blasts away the protective ceramic granules, voids your manufacturer's warranty, and leaves the roots of the algae alive.
Instead, Crosswater Exterior Cleaning LLC utilizes Soft Washing—a gentle, low-pressure treatment standard approved by the Asphalt Roofing Manufacturers Association (ARMA).
Our Secret Weapon: Sodium Hypochlorite
We apply a custom-blended solution using Sodium Hypochlorite, the industry gold standard for roof preservation:
Chemical Elimination: It chemically breaks down and kills algae, moss, and lichen at the root level rather than just shaving off the top layer.
Zero Erosion: It is applied with the same gentle pressure as a garden hose, ensuring your shingles experience zero physical wear.
Extended Treatment Time: We do not rinse the solution off your roof. Leaving it on allows the treatment to continue working long after we pack up our truck. The next heavy rain will naturally rinse away the dead organic debris, giving your roof a deeper, cleaner wash.