If you are seeing green clumps creeping across your shingles or dark streaks running down the shaded side of your roof, that is moss and algae, and it does not clear up on its own. I am Tomer, and I do this work myself. I am already up on roofs all over Pittsburgh every week for chimney work, so cleaning a roof the safe way is something I handle hands-on from start to finish. Here is how I do it, why moss hits roofs so hard here, and what you actually get out of the job.
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A Pittsburgh Roof I Just Cleaned
The photos here are from a recent job on a shaded, tree-covered lot. The roof had gone almost solid green, with moss packed across the slope and branch debris piled in it. I soft-washed it, cleared the dead moss off by hand, cut back the limbs feeding it, and cleaned out the gutters. Same roof, same shingles, just no longer buried under moss holding water against the roof.
Why Moss Is a Problem on Pittsburgh Roofs
Pittsburgh gives moss everything it needs. Our summers are humid, and the spring and fall shoulder seasons stay wet for weeks at a stretch, so a roof barely gets a chance to dry out. Then there is the tree cover. A lot of the streets I work sit under mature oaks and maples that throw shade over the roof all day long, the older parts of Mt. Lebanon, the wooded lots up around Wexford and Cranberry, and the hillsides out through the Alle-Kiski Valley. The north-facing and valley-facing slopes down in the river valleys are the worst of it. They get almost no direct sun, they hold damp, and moss takes hold there first.
Winter is where the real damage happens. Moss soaks up water like a sponge and holds it against the shingles. When that water freezes it expands, and it pries the shingle edges up a little more with every freeze-thaw swing we get through a Pittsburgh winter. Come spring the moss is thicker, the shingles are lifted, and water has a clear path underneath to the wood decking. On the older slate and asphalt roofs around here, sitting on hilly, shaded lots, that is exactly how a cosmetic problem turns into a leak.
My Roof Cleaning Process
I treat roof cleaning as one job that fixes the cause, not a quick spray that hides the symptom. Four steps, every time.
1. Soft-Wash Moss and Algae Treatment
I start with a low-pressure soft wash using a roof-safe solution that kills the moss and the algae streaks down at the root, not just on the surface. This part matters: I do not pressure wash roofs, and you should not let anyone do it to yours. High pressure blasts the protective granules off asphalt shingles, drives water up underneath them, and voids most shingle manufacturer warranties. A soft wash cleans the roof at a pressure that will not tear it up.
2. Physical Moss Removal
Once the treatment has killed it, I clear the moss buildup and debris off the roof by hand. Browning the moss out and leaving it up there is only half a job. Dead moss still holds moisture against the shingles the same way living moss does, and that trapped damp is what shortens a roof's life. So I get it off the roof and out of the valleys for real, not just dead in place.
3. Tree Branch Trimming
Next I cut back the limbs hanging over the roof. Two reasons. Less shade means the roof actually dries out between rains instead of staying wet, and fewer branches overhead means fewer spores dropping onto the shingles to reseed the moss you just paid to clear. Pulling the canopy back off the roof is one of the biggest things that keeps it clean longer.
4. Gutter Cleaning
Last, I clean the gutters. A moss job knocks a lot of material loose, moss, loose granules, and leaf debris, and a good bit of it lands in the gutters. I clear all of it so water drains the way it should. Clogged gutters back water up under the shingle edges and rot the fascia, which undoes the whole point of cleaning the roof in the first place.
Done together, these four steps go after the cause. Most outfits stop at killing the moss. I treat it, remove it, cut back what feeds it, and clear the drainage, so the roof stays clean a lot longer than a spray-and-go ever will.
What You Get
- A longer roof life. Clearing the moss before it lifts the shingles protects the roof you already paid for instead of pushing you toward an early replacement.
- Your curb appeal back. The green clumps and the black algae streaks are gone, and the roof looks like itself again.
- No moss-driven leaks. Pulling the moss out of the field and the valleys closes off the paths water uses to sneak under the shingles.
- Drainage that works. Clean gutters and clear valleys move water off the roof fast, the way it was built to.
Why Homeowners Call Me
I am owner-operated. When you call, you get me, not a crew that got sent out after a salesman came first. I show up, I do the work myself, and I am from here, so I know how these roofs and these shaded river-valley lots behave through a wet Pittsburgh year. I will tell you straight whether your roof needs a full cleaning or just a treatment, and I will not talk you into work it does not need.
Where I Work
I clean roofs across Pittsburgh and the suburbs, including Mt. Lebanon, Cranberry, Wexford, and out through the Alle-Kiski Valley. You can see the full list of areas I cover. If your roof is shaded, wooded, or just has not been touched in years, that is exactly the kind of roof I am on every week. This work is closely tied to my roof moss removal service, so it is a natural part of what I already do up there.