Roof cleaning in Arlington Heights, without the pressure

What's growing on your roof

Most roofs in the Chicago suburbs that look “dirty” are actually covered in organic growth. There are usually three culprits:

• Algae. The long black streaks running down a roof are almost always a type of algae. It spreads by wind and rain from roof to roof, which is why whole blocks often look streaked. What those black streaks are.
• Moss. Green, spongy clumps that hold water against the shingles and can lift their edges over time.
• Lichen. Flat, crusty spots that grip the surface tightly and are the slowest to let go.

All three thrive on the shaded, north-facing slopes that stay damp after rain, and Arlington Heights has no shortage of mature trees casting that shade.

Signs your roof needs cleaning

You don't need to climb a ladder to check. From the street or the yard, look for:

• Dark vertical streaks running from the ridge toward the gutters.
• A green or gray tint on one side of the roof, usually the north or the side under trees.
• Clumps of moss along shingle edges, in valleys or on the shaded lower rows.
• Pale, crusty spots that look like paint splatter. That's lichen.
• A roof that looks older than it is. If your neighbors' roofs of the same age look lighter, growth is usually the difference.

If you see any of these, the growth is already established, and it will keep spreading across the roof until it's treated.

Moss needs extra care in a Chicago winter

Moss deserves its own mention because it does more than stain. It works like a sponge, holding water against the shingles long after the rest of the roof has dried. In the Chicago suburbs, that water freezes and thaws over and over through the winter, and each cycle can pry at the edges of the shingles the moss is sitting on.

Scraping or blasting moss off makes the problem worse, because it tears away shingle granules along with it. We treat the moss first so it dies and releases its grip, then remove the loosened clumps gently by hand. What's left washes away with the following rains.

Why roofs should never be pressure washed

A pressure washer can make a roof look clean for a few weeks, but it does real damage along the way:

• It strips the mineral granules that shield shingles from sun and weather, which shortens the life of the roof.
• It can force water under shingles and into the roof deck.
• It removes the visible stain but leaves the roots of the growth behind, so the streaks come back quickly.

Asphalt shingle manufacturers and the industry's trade association advise against pressure washing roofs for these reasons. Soft washing is the method they point to instead. Why we never pressure wash a roof.

Our soft wash roof cleaning process

1. Inspect and quote. We look at the roof type, the growth, the pitch and what's planted below, then give you a clear price.
2. Protect the property. Plants, shrubs and lawn under the roofline are soaked with water first, and downspouts are managed so runoff is diluted.
3. Apply the solution. A cleaning solution matched to your roof is applied at low pressure, with no one walking on fragile areas more than necessary.
4. Let it work. The solution kills the algae, moss and lichen at the root. Heavy moss is loosened and removed by hand where needed.
5. Rinse and check. Plants and surfaces below are rinsed again, and we walk the property with you when the job is done.

Some staining fades further over the following days as rain washes away the dead growth. That's normal, and it's a sign the growth was killed rather than just knocked loose.

Roofs we clean

Our roof cleaning services cover the roofs you see most around Arlington Heights:

• Asphalt shingles. The most common roof in Arlington Heights, and the one most prone to black algae streaks.
• Cedar shake. Cleaned at low pressure so the wood doesn't get furred or splintered.
• Other roof types. Ask us about your roof. If a surface can't be safely soft washed, we'll tell you.

Roof cleaning and shingle warranties

A common worry is whether cleaning a roof will void its warranty. The risk comes from high pressure and harsh scrubbing, which can damage shingles. Low-pressure soft washing with an appropriate cleaning solution is the approach shingle manufacturers recommend for removing algae. If you have a specific warranty in mind, check its terms or send it to us, and we'll talk it through before any work is done.

Protecting your plants, gutters and downspouts

Runoff from a roof cleaning ends up in your gutters, downspouts and garden beds, so we plan for it. Plants are pre-wetted and rinsed again afterward, runoff is diluted, and we can brighten your gutters in the same visit so the black stripes on the gutter faces don't undo the clean roof above them.

How long does a clean roof stay clean?

Because soft washing kills the growth instead of just removing the stain, results last much longer than a pressure wash. How long depends on shade, tree cover and how exposed the roof is. Shaded roofs under big trees will see growth return sooner than open, sunny ones. Trimming overhanging branches and keeping gutters clear both help.

Cleaning a roof before you sell

A streaked roof is one of the first things buyers notice in listing photos, and it can make a sound roof look like it needs replacing. A soft wash before you list lets the roof show its real condition. If you're selling, give yourself a few weeks between the cleaning and the photos, so any remaining shadow has time to wash away with the rain.

What roof cleaning doesn't fix

Cleaning removes growth. It doesn't repair a roof. Missing or cracked shingles, curling edges, damaged flashing and leaks are jobs for a roofer. If we notice something like that from the ground or while we work, we'll point it out so you can have it checked, but we won't sell you a repair we don't do.