They’re three different organisms that look similar but behave differently. Gloeocapsa magma is a cyanobacteria that causes the dark vertical streaks on asphalt shingle roofs — it feeds on the limestone in modern shingles. Common green algae causes the discoloration you see on shaded siding and fences and feeds on moisture and surface debris. Mildew is a fungus that thrives in damp areas and tends to be more powdery in appearance. All three respond to similar soft-wash treatments, but the dilution ratios and dwell times differ slightly. We identify which organism we’re treating before applying any solution.

Because pressure washing only removes the visible top layer of the organism — it doesn’t kill the spores or the cellular structures left behind in the substrate. The colony regenerates from those remnants within weeks to months. Worse, pressure washing on shingles strips protective granules and on softer surfaces like siding can force water behind the substrate. Soft washing with the proper chemical solution kills the organism at the spore level so it can’t simply regrow.

Properly treated surfaces typically stay algae-free for 3 to 5 years in the Brentwood area. The exact window depends on tree cover, surface orientation, humidity exposure, and how thoroughly the original treatment was applied. Heavily shaded north-facing surfaces will see faster regrowth than open south-facing ones. We can apply optional preventive treatments during follow-up service that extend the algae-free window further.

Pricing varies by what’s being treated and the affected area. Roof algae and black streak removal usually runs $400–$900 depending on roof size and pitch. Siding algae treatment is typically included with a house wash service ($350–$700 for most homes). Fence and standalone surface treatment depends on linear footage. We provide written estimates with flat pricing after a property walk-through — no hourly billing, no upsells.

Yes, when applied correctly. The sodium hypochlorite solution we use is biodegradable and breaks down rapidly when diluted and rinsed. Our crews pre-wet all landscaping around the treatment area, dilute the solution to plant-safe ratios, tarp particularly sensitive plants when needed, and post-rinse adjacent foliage thoroughly. We’ve cleaned thousands of Brentwood homes adjacent to mature gardens, vegetable beds, and sensitive ornamentals without incident.

Yes — lichen is actually one of our common requests. Lichen is the toughest of the three to remove because it’s a symbiotic combination of fungus and algae that anchors more aggressively into surfaces. We use an extended-dwell treatment that gives the solution more time to penetrate, and we may do a second application on heavily affected areas. The dead lichen will continue to weather off naturally for several weeks after treatment, which is normal.

Most surfaces look dramatically improved the same day. Asphalt shingle roofs typically show 80–90% improvement within a few hours, with full color restoration over the following 24–48 hours as the dead algae completely washes away. Siding and fences usually show full results within hours. Heavy lichen colonies may continue to weather off and improve over several weeks — the organism is dead immediately, but the residue takes time to fully release from the surface.

Yes — we treat algae and biological staining on natural stone, concrete pavers, brick walkways, and stamped concrete. The treatment is similar to what we use on siding but with adjusted dilutions appropriate for the substrate. This service is often combined with paver cleaning or paver sealing for a complete restoration.