Asphalt shingles are the most common roof type in the Waldorf area and the most susceptible to Gloeocapsa Magma algae — the black streaking you see on roofs across Southern Maryland. This organism feeds on the limestone filler in shingles, and the dark colouring absorbs heat and accelerates granule loss. Beyond the aesthetic problem, it genuinely shortens shingle life. We clean asphalt shingles using the ARMA-recommended soft wash method — low pressure, correct chemistry, no granule stripping.

Metal roofing is durable but it accumulates algae, mold, and atmospheric deposits in the same way as other roof types. The critical factor with metal is using the right cleaning solution — some chemicals react badly with metal coatings and cause staining or corrosion. We use chemistry that's safe for all metal roof finishes and coatings, and apply it at low pressure to avoid any surface damage.

Tile roofs are common in parts of Southern Maryland and they develop significant moss and lichen growth because the surface texture and porosity create ideal conditions for organic growth. We clean clay and concrete tile roofs using soft wash methods that remove moss, lichen, and algae without cracking tiles or disturbing their placement. High-pressure washing on tile roofs is a fast way to cause expensive damage — soft washing is the correct approach.

Cedar shake requires the most careful approach of any roof type. The wood is naturally more fragile than manufactured roofing materials and high pressure will split, crack, or fray the shakes. We use a gentle soft wash treatment specifically formulated for wood roofing that cleans thoroughly without damaging the wood fibre. A clean cedar shake roof also absorbs preservative treatments better, extending its life significantly.

Slate is one of the most durable roofing materials available, but the fastening system that holds slate tiles in place is vulnerable to high-pressure washing. We clean slate roofs at very low pressure using soft wash chemistry that removes moss, algae, and lichen without disturbing the tiles or their fixings.

Moss is more than a cosmetic issue. Moss retains moisture against the roof surface and causes the underlying material to stay wet for extended periods — leading to rot in wood structures and deterioration in shingle and tile surfaces. Physical moss removal combined with biocide treatment is the correct approach. We remove the moss and apply a solution that kills remaining spores and slows regrowth significantly.

Black streaks on roofs across the Waldorf area are almost universally caused by Gloeocapsa Magma — an algae that spreads by airborne spores and is endemic to the humid Southern Maryland climate. It can spread from one house to the next in a neighbourhood, which is why you often see multiple homes on the same street developing similar staining at the same time. Our soft wash treatment kills the organism completely.

Lichen is the most stubborn organic growth you'll find on a roof. Unlike algae and moss, lichen bonds physically to the roofing surface — its root-like structures penetrate into the material. Removing lichen requires the right chemical treatment applied and allowed to dwell long enough to break down the bond. Pressure washing attempts to remove lichen by force and takes pieces of the roofing material with it. We do it right.

After cleaning, we apply a preventative biocide treatment to the roof surface that significantly slows the regrowth of algae, moss, and lichen. Think of it as a protective layer that makes the roof inhospitable to organic growth for an extended period. Most treated roofs in the Southern Maryland climate stay noticeably cleaner for 12–24 months after treatment.