What are the black streaks on my roof?
Those dark stains are caused by Gloeocapsa Magma, an airborne algae that feeds on the limestone filler in asphalt shingles. It spreads across your entire roof over time, accelerating shingle breakdown and potentially voiding manufacturer warranties. Moss and lichen cause even more physical damage by lifting shingles and allowing water infiltration.
Our soft wash roof cleaning process
We follow ARMA (Asphalt Roofing Manufacturers' Association) guidelines — low-pressure application of professional-grade cleaning solutions that kill algae, mold, and moss at the root. No high-pressure blasting that strips granules or causes leaks. Results are visible the same day.
Why not pressure wash a roof?
High-pressure washing strips the protective granules from asphalt shingles, can force water under flashing, and will void most roofing warranties. Soft washing is the manufacturer-recommended method — it cleans thoroughly and safely, and the results last years longer because it kills biological growth at the source rather than just blasting the surface.
Where we serve
We wash roofs throughout the NH Seacoast including Portsmouth, Exeter, Dover, Durham, Hampton, Stratham, Lee, Nottingham, Barrington, Rye, North Hampton, and all surrounding communities. We also serve Southern Maine (Kittery, York, Berwick, Eliot) and the NH Lakes Region (Wolfeboro, Alton, Gilmanton, New Durham, Barnstead).
Roof washing cost in NH
Roof washing starts at $400 for most NH homes and increases based on roof size, pitch, and the extent of algae, moss, or lichen growth. A heavily colonized roof with established moss or thick lichen requires more solution and dwell time than a roof with early-stage algae streaking. We provide free estimates and give you an honest assessment before starting. All pricing is confirmed upfront — no surprises.