Question 1

What actually causes the dark streaks running down my roof?

Accepted Answer

It is a cyanobacteria called Gloeocapsa magma. It survives on the limestone filler baked into asphalt shingles and travels on the wind, which is why streaks usually appear on the north-facing plane first and why one house on a street gets it while the neighbour does not. The dark protective sheath the colony forms is the stain — no amount of rinsing removes a living colony.

Question 2

Why is the roof rinsed at low pressure instead of pressure washed?

Accepted Answer

Asphalt shingles hold their UV protection in a bonded granule layer. Direct pressure lifts those granules, exposes the mat and takes years off the roof, and every major shingle manufacturer treats it as installer or owner damage. A soft wash applies the cleaning solution, gives it dwell time to kill the growth, and rinses at roughly garden-hose pressure so nothing mechanical touches the surface.

Question 3

Is a roof wash safe on concrete tile and metal roofs?

Accepted Answer

Yes, with different handling. Concrete tile is brittle underfoot, so we work from ladders, walk boards and roof planes only where the tile profile supports it, and we watch valley flashing for pooling. Standing-seam and corrugated metal cleans quickly but needs a full rinse of every lap and fastener line so no solution dries on the coating.

Question 4

What happens to my plants, lawn and pets during a roof wash?

Accepted Answer

Beds under the drip line get pre-wetted and tarped where needed, downspout discharge is diverted away from planting, and everything is flushed with clean water on the way out. Pets stay inside for the visit and can go back out as soon as the surfaces are rinsed and drying — typically right after we pack up.

Question 5

How soon will the roof look clean?

Accepted Answer

Most of the change is visible the same day, but roof cleaning is the one service that keeps improving after we leave. Dead algae and lichen release over the following two to six weeks with sun and the first rain, so a roof that looks 80% better at pack-up usually reads fully clean by the next month.

Question 6

Can a roof wash stop leaks or replace a repair?

Accepted Answer

No, and we will say so on site. Cleaning removes growth that holds moisture against the surface, which helps the roof dry and drain, but a cracked tile, failed boot or lifted flashing needs a roofer. If we spot one during the wash you get a photo of it and a plain description of what we saw, with no upsell attached.

Question 7

How much does roof cleaning cost, and can it be bundled?

Accepted Answer

Roof washing is quoted per roof after we see pitch, access, story count and how much growth is on the surface, and every quote is in writing before we start. Standalone visits meet the $297 minimum; bundling the roof with a house wash or gutter clean-out on the same trip is where the savings are, because the setup and access cost is shared.

Question 8

How often should a Central Valley roof be cleaned?

Accepted Answer

Every three to four years suits a sunny, well-drained roof here. Move to every two years if you sit under mature oaks or walnut canopy, if sprinklers hit the eaves, or if the north plane is permanently shaded — those roofs stay damp long enough for algae and lichen to re-establish quickly.

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