Most homeowners simply call it "mold," but exterior staining can actually be caused by several different organisms, including mold, mildew, algae, moss, lichen, and Gloeocapsa magma. Knowing which one you're dealing with helps determine the most effective treatment.
At HiCleaners, we identify the biological growth affecting your property and treat it at the source rather than simply washing away surface staining. We provide exterior mold, mildew, and algae removal throughout Massachusetts and Southern New Hampshire for both residential and commercial properties.
What's actually growing on your exterior?
Many people use the term "mold" to describe any exterior biological growth, but the staining on a home may actually fall into several different categories:- Mold – thrives in damp, shaded areas with poor airflow; often appears as dark, fuzzy or spotted patches;
- Mildew – a surface-level fungus, typically gray or white, common on siding and painted surfaces;
- Algae – the green film most homeowners notice on north-facing walls, roofs and decks;
- Gloeocapsa magma – the cyanobacteria responsible for the black streaks commonly found on asphalt shingle roofs;
- Lichen and moss – the most stubborn growth, often found on roofs and shaded masonry, physically bonded to the surface.
Each behaves differently and calls for a slightly different treatment approach – which is exactly why identifying what you're dealing with matters before any cleaning starts.
Why Massachusetts homes are especially prone to this
New England gives biological growth almost everything it needs. Humid summers keep exterior surfaces damp for extended stretches. Mature tree cover throughout Massachusetts creates shaded, low-airflow conditions on north-facing walls and rooflines. A long, wet fall keeps organic debris sitting against siding and in gutters well into the colder months. Coastal humidity adds another layer for homes near the water.Over time, many properties throughout the region develop some degree of mold, mildew, algae, or other biological growth. The exact type varies, but the conditions that allow it to develop are common across Massachusetts and Southern New Hampshire.
Why it's a problem, not just an eyesore
Exterior biological growth affects more than curb appeal. Depending on where it develops, it can contribute to material deterioration, create slippery walking surfaces, and make exterior maintenance more difficult over time.Left alone, exterior growth doesn't stay put – it spreads, and it causes real damage along the way:
- It continues to spread over time. Left untreated, mold, mildew, and algae expand across the surface and often migrate to new areas.
- It can trap moisture against exterior materials. That trapped moisture accelerates material degradation – paint failure, siding rot, shingle granule loss.
- Some forms of biological growth can release spores that may contribute to allergens for sensitive individuals.
- It creates slip hazards. Algae and moss on decks, walkways, and steps become dangerously slick when wet.
Our goal is to treat biological growth at its source rather than simply removing surface staining, helping slow regrowth compared with cleaning methods that address appearance alone.
Keep exterior mold from taking over your home
Most homeowners don't think much about exterior mold until they notice green or black staining spreading across larger sections of the home. By then, the growth has often been developing for months.Protect your home's appearance while helping preserve the siding, roofing, and other exterior surfaces that protect your property year-round. The earlier biological growth is addressed, the easier it is to keep exterior surfaces looking their best.
Beyond improving curb appeal, many homeowners simply want the biological growth properly addressed instead of temporarily rinsed away. Our treatments are biodegradable, we take precautions around surrounding landscaping, and we work carefully around your property throughout the service.
Why homeowners choose HiCleaners: biodegradable, plant-conscious treatments, fully insured, background-checked technicians, treatment aimed at the root of the growth, not just the surface, available 7 days a week.
Commercial mold, mildew and algae treatment
First impressions matter for commercial properties. Visible mold, mildew, or algae on exterior facades can make an otherwise well-maintained property appear neglected to tenants, visitors, and customers.For commercial buildings, HOAs, and apartment complexes, visible biological growth can create the impression of deferred maintenance for tenants, customers, and inspectors alike. On walkways, entryways, and other shared areas, biological growth can also increase slip hazards. We offer scheduled treatment programs with General Liability Insurance, COI available upon request, and flexible scheduling around business hours.
Where it shows up
Exterior biological growth can develop on many different surfaces, but each requires its own cleaning approach. Rather than treating every material the same, we evaluate the affected surface and recommend the appropriate service.For black roof streaks, moss, and lichen, see our Roof Cleaning service. For algae and mildew on siding or building facades, see Exterior House Cleaning. Hard surfaces such as concrete and walkways are handled through Pressure Washing, while our Soft Washing page explains the low-pressure cleaning method we use on delicate exterior surfaces.
Exterior mold removal throughout Massachusetts and Southern New Hampshire
We provide exterior mold, mildew, and algae removal throughout Massachusetts and Southern New Hampshire, including Greater Boston, the North Shore, South Shore, MetroWest, and North of Boston.Remove exterior mold, mildew, and algae with a treatment designed to address the source.
Free estimate within hours. No obligation.
781-333-8758 – request a free estimate today.
Fully insured · Treated at the root · Biodegradable solutions.
