I used to think roof moss was mostly cosmetic. Then I started seeing what was happening underneath it.

From the driveway, most mossy roofs don’t look urgent. A few green patches, maybe a darker strip on the north side. That’s usually why people leave them alone. Honestly, before I started spending my days around roofs, I probably would have thought the same thing.

What changed my mind wasn’t a dramatic before-and-after photo. It was seeing what can be sitting underneath a patch that looks harmless from the ground: moisture that hangs around longer than it should, moss working its way around the edges of shingles, and gutters filling up with the stuff that comes loose.

That doesn’t mean every green roof is an emergency. It does mean it’s worth looking at properly before someone starts blasting it with a pressure washer—or before it gets ignored for another few wet winters.

The part homeowners can’t really see from the ground

Roofs on the Island spend a lot of the year damp. The shaded side of a home can stay wet long after the driveway and siding have dried. That’s a comfortable place for moss and algae to keep growing.

The issue isn’t that moss looks bad. The issue is that a thick patch can hold moisture against the roof and make it harder to see what shape the shingles are actually in.

Sometimes we get up there and the roof is in good condition and just needs a careful clean. Sometimes the moss is telling us there’s a bigger roofing issue and cleaning isn’t the first thing the homeowner should spend money on. That’s why I don’t love quoting a roof from one blurry photo and pretending we know the whole story.

Please don’t let somebody pressure-wash your shingles

A pressure washer makes for satisfying video because the change is instant. It can also be far too aggressive for an asphalt roof. You don’t want someone trading a quick cosmetic result for unnecessary wear, water pushed where it shouldn’t go, or damage around vents and flashing.

Our approach is lower pressure and slower. The goal is to treat the growth, protect the roof and the property around it, and let the process do the work. It isn’t as dramatic as carving a clean line with a pressure washer. It is the way I would want my own roof handled.

Does your roof actually need cleaning right now?

You may want somebody to take a closer look if:

• the moss is more than a light surface dusting;
• growth is collecting along shingle edges or in the valleys;
• the shaded side stays green even through the drier months;
• pieces are washing into the gutters or onto the ground; or
• you can’t tell whether you’re looking at staining, moss, or worn shingles.

What I’d do if it were my house

I’d start with an inspection, not a cleaning package. Have someone look at the roof, take clear photos, and explain what they see in normal language. If it needs cleaning, you should understand why and how it will be done. If it needs a roofer instead, you should know that before paying for a wash.

That’s the whole idea behind the inspections our team does. There’s no need to decide anything from this page. We’ll look at the roof, show you what we see, and give you a straightforward recommendation.