Most roof maintenance mistakes come from good intentions. A dark-streaked roof looks dirty, so it gets pressure washed. Leaves pile up, so someone climbs up with a broom. Gutters get forgotten until water pours over the edge in the next storm.
This guide covers the common roof maintenance mistakes on asphalt shingle roofs in Plano and across North Texas, what the shingle industry actually recommends instead, and which jobs belong to a professional. It does not tell you to climb onto your roof. Everything you need to check yourself can be done from the ground, a window or the attic hatch.
What are the most common roof maintenance mistakes?
The most common roof maintenance mistakes are pressure washing shingles, scrubbing or sweeping debris hard across the surface, letting gutters clog, adding metal strips or fasteners to an existing roof, and climbing up to do the work yourself. Each one either strips the protective granules, breaks the shingle seal, or traps water where it causes damage.
Here they are side by side, with what to do instead:
| Mistake | What it can do | Better approach |
|---|---|---|
| Pressure washing shingles | Strips granules and can shorten roof life | A professional low-pressure cleaning method, or leave cosmetic algae alone |
| Hard sweeping or scraping | Abrades the surface and loosens granules | Non-abrasive debris removal by a professional |
| Clogged gutters | Water backs up and overflows at the roof edge | Regular gutter cleaning and repair |
| Upper roof draining onto lower roof | Concentrated water wears one area | Extend the downspout into the lower gutter |
| Adding zinc or copper strips later | Exposed nails or a broken sealant bond | Algae-resistant shingles at replacement time |
| Doing it yourself on the roof | Falls, and damage to the shingles you walk on | Check from the ground and attic; hire out roof work |
Is pressure washing shingles a roof maintenance mistake?
Yes. Pressure washing is the clearest roof maintenance mistake on asphalt shingles. The Asphalt Roofing Manufacturers Association warns never to use a pressure washer on an asphalt shingle roof, because it causes granule loss and very likely premature failure of the roof system. The stains it removes are usually cosmetic anyway.
The Asphalt Roofing Manufacturers Association (ARMA) guide to algae and moss prevention and cleaning is blunt on this point. A pressure washer will cause granule loss, and very likely premature failure of the roof system.
Granule loss is the damage mechanism ARMA names. For more on what granule loss looks like and when it signals a problem, see our guide to shingle granule loss and when it means trouble.
If a cleaning contractor offers to pressure wash your shingle roof, that offer is itself a reason to look elsewhere.
Are black streaks on a roof actually damaging it?
Usually not. The dark streaks on many North Texas roofs are algae, not mold, dirt or failing shingles. ARMA states there is no scientific evidence that algae damages asphalt shingles, although it affects how the roof looks. Moss is different and can cause harm. Knowing which one you have prevents an unnecessary, damaging cleaning job.
ARMA’s guidance explains that the black discoloration and streaks seen on many roofs across the United States and Canada are actually algae, often mistaken for mold or mildew. The most common type produces a dark pigment that protects it from ultraviolet light. Algae forms where moisture tends to stay on the roof surface, and its spores are carried by wind and animals, which is why whole neighbourhoods can show it at once.
There is one exception worth knowing. ARMA notes that on highly reflective or “cool” roofs, algae will have a negative impact on the long-term effectiveness of those roofs. If your roof was chosen for its reflectivity, discoloration is more than cosmetic.
Moss is a separate problem. ARMA says moss can be detrimental to asphalt shingle performance. It can make the leading edges of shingles lift or curl, which raises the risk of shingle blow-off in high wind. In severe cases, moss build-up can push water sideways, damaging the roof deck or causing leaks.
So the first question is not “how do I clean it?” but “is this algae or moss?” A professional inspection answers that from close range.
How should a stained or mossy roof be cleaned?
If a roof needs cleaning, it should be done with a low-pressure chemical wash by a professional working with fall protection, not with a pressure washer or a stiff brush. ARMA describes a bleach-and-water solution applied with a sprayer and rinsed with low-pressure water. Landscaping must be protected, and protective equipment worn.
ARMA’s cleaning method relies on chemistry, not force. The solution is left to dwell on the roof surface for a set time and then rinsed with low-pressure water. Algae then washes away with later rains. Moss loosens over time, and ARMA notes that in severe cases more than one treatment may be needed.
This article does not give the mixing instructions, because the work happens on a sloped roof that is wet and slippery from the solution itself. A chemical wash on a pitched roof is professional work. Ask any cleaning contractor:
- What method do you use? The answer should be low-pressure. If it involves a pressure washer on the shingles, decline.
- How do you protect plants and the lawn? ARMA specifically calls for protecting landscaping and surrounding areas from the bleach solution.
- How do your crews work safely on the roof? Ask about fall protection.
- Will you check with the shingle manufacturer’s guidance? Your shingle brand may have its own cleaning advice.
Or leave cosmetic algae alone. On an ordinary asphalt roof, ARMA’s position is that algae affects appearance, not performance.
Is sweeping or scraping debris off a roof safe for shingles?
Not when it is done hard or by hand on the roof. ARMA recommends clearing debris with a leaf blower or similar non-abrasive method as part of regular maintenance, with airflow directed down the slope so debris is not driven under shingle edges. Stiff brooms, rakes and scrapers grind against the granules and risk the shingle seal.
ARMA’s maintenance advice includes two details that explain why technique matters:
- debris should be cleared with a non-abrasive method;
- the airflow should be aimed down the slope, to avoid driving debris under the edges of the shingles.
Debris itself is a moisture trap. ARMA notes that overhanging branches shade the roof and drop debris that holds moisture and feeds moss. Its prevention advice is to trim branches back to let more sunlight reach the roof and to reduce how much debris collects.
Tree trimming near a roofline, and anything involving ladders or roof access, is work for a professional. From the ground, you can still watch for leaves piling in valleys and behind chimneys, and branches touching or hanging over the roof. Those are the spots to point out when you book a maintenance visit.
Why do clogged gutters cause roof problems?
Clogged gutters cannot carry water away, so it overflows at the roof edge, soaks the fascia and can back up toward the roof and down the walls. Both ARMA and the U.S. Environmental Protection Agency list gutter cleaning as routine moisture control. Neglecting it is one of the easiest roof maintenance mistakes to avoid.
ARMA’s guidance says to keep gutters clean to promote proper water drainage. The EPA’s brief guide to mold, moisture and your home gives the same instruction in its moisture-control tips: clean and repair roof gutters regularly. The EPA links that advice to keeping water from collecting where it can cause mold.
ARMA adds a design point that is easy to miss on homes with more than one roof level. Gutters from an upper roof should not drain directly onto a lower roof. Instead, the downspout from the upper roof should be extended into the lower gutter. A downspout that dumps onto shingles concentrates water and wear on one small patch.
Signs of gutter trouble you can see from the ground:
- water spilling over the front edge during rain;
- plants or seedlings growing in the gutter line;
- gutters pulling away from the fascia or sagging between hangers;
- staining on siding or fascia below the gutter;
- a downspout from an upper roof emptying onto lower shingles.
Gutter cleaning involves ladders at height. Hire it out if you are not equipped to work safely.
Can adding zinc or copper strips hurt an existing roof?
It can. ARMA says adding zinc or copper strips to an existing roof is not recommended, because the strips must either be fastened with exposed nails that can cause leaks over time, or slid under shingles in a way that breaks the sealant bond. Algae-resistant shingles are the cleaner fix, chosen at replacement time.
ARMA’s guidance notes that algae-resistant shingles are available that use copper granules or similar technology. It treats metal strips and algae-resistant shingles as measures to consider when it is time to replace a roof, not as add-ons for an existing one.
The sealant bond matters more than it looks. The Insurance Institute for Business & Home Safety (IBHS) has found, in research on asphalt shingle durability, that sealant strength is a critical factor in resisting wind damage, particularly after hail impact. Any maintenance step that lifts shingles to slide something underneath weakens the very bond that keeps them on in a storm.
How does the North Texas climate change roof maintenance?
North Texas roofs face hail, strong thunderstorm wind and summer heat more than moss or snow. That shifts maintenance toward checking for storm damage, keeping gutters flowing before the spring storm season, and managing attic heat. It also means the riskiest mistake is climbing onto a roof after a storm to look.
According to the NOAA National Centers for Environmental Information Storm Events Database, the Plano area logged 310 hail reports on 62 separate days from 2016 to 2025, and 108 thunderstorm wind reports over the same years. Those are reports, not a full count of every storm, but they show how often the roof is tested.
Heat is the steady background stress. ARMA’s bulletin on attic ventilation says heat buildup in an attic may accelerate the ageing of asphalt roofing products. Blocked intake vents are a maintenance issue a professional can spot from the attic.
Winter is short but not harmless. For what a hard freeze can do to gutters, flashing and shingles, read whether a Texas freeze or ice storm can damage your roof.
What roof maintenance can you safely do yourself?
You can do a great deal from the ground and the attic hatch: look for missing or lifted shingles, dented vents and gutters, overflowing gutters, branches over the roof, and attic stains or daylight. Keep a dated photo record. Leave anything that needs a ladder at height, a roof walk or chemicals on the roof to a professional.
A simple seasonal routine:
- After every major storm, walk the perimeter and look at the roof edges, ridge, gutters and soft metal for dents or missing pieces.
- Before spring storm season, book gutter cleaning and check downspouts drain away from the house.
- Each summer, look in the attic from the hatch with a flashlight for stains, damp insulation and blocked vents. Do not walk out onto the joists.
- Once a year, photograph each side of the roof from the ground so you can compare year to year.
- Any time you see a ceiling stain, note the date and weather and arrange an inspection.
This record helps whoever inspects the roof and helps if you ever need to talk to your insurer. Coverage and any maintenance conditions are set by your policy, so confirm with your insurer rather than assuming.
The wider picture, from hail preparation to insurance and safety, is in our guide to protecting a Plano home from hail, with insurance and safety basics.
When should you call a professional for roof maintenance?
Call a professional for anything that needs roof access: cleaning algae or moss, clearing debris from the roof surface, gutter work at height, trimming branches over the roof, and any repair. Also call after a significant storm, or when you see lifted shingles, granule piles, sagging gutters or ceiling stains from the ground or attic.
A good maintenance visit should come with photographs and written findings, not just a verbal “looks fine”. Ask what was checked: shingles, flashing, vents, sealant at penetrations, gutters and the attic.
Roofing Repair Plano offers scheduled roof maintenance in Plano built around those ground, roof and attic checks, with the findings documented for your records.
Frequently asked questions
Can you pressure wash asphalt shingles?
No. The Asphalt Roofing Manufacturers Association says never to use a pressure washer on an asphalt shingle roof, because it causes granule loss and very likely premature failure of the roof system. If a roof needs cleaning, a professional low-pressure chemical wash is the method the industry describes instead.
Are the black streaks on my roof mold?
They are usually algae, not mold. ARMA explains that the black streaks seen on many roofs are algae, which grows where moisture lingers. It says there is no scientific evidence algae damages asphalt shingles, though it affects appearance and can reduce the performance of highly reflective cool roofs.
How often should gutters be cleaned?
Regularly, and especially before the spring storm season in North Texas. The EPA advises cleaning and repairing roof gutters regularly as part of moisture control, and ARMA says to keep gutters clean for proper drainage. Trees close to the house fill gutters faster, so those homes need more frequent attention.
Is it safe to clean my own roof?
It is not recommended. Pitched roofs are a fall hazard, and cleaning solutions make the surface slippery. Walking and scrubbing can also damage the shingles. Check from the ground and the attic hatch, and hire a professional with fall protection for any cleaning, debris removal or repair on the roof.
Is moss on a roof a problem?
Yes, more than algae. ARMA says moss can lift or curl the leading edges of shingles, which increases the risk of blow-off in wind, and severe build-up can push water sideways into the roof deck or cause leaks. Have it assessed and treated by a professional rather than scraped off.
