Why Is My Roof Streaky? Here’s What You Need to Know

If you’ve noticed black streaks, moss, or patches of discoloration on your roof, you’re not alone. These stains are common and may seem like a minor issue at first, but they can lead to bigger problems if ignored.

The most common cause of roof streaking is algae, specifically, a type called Gloeocapsa magma. It spreads through airborne spores and tends to thrive in warm, humid environments. Once it lands on your roof, it starts to grow, especially on shaded areas where moisture hangs around. Over time, you might also see moss or lichen, which can cause even more damage by holding moisture against the surface of your shingles.

These growths aren’t just cosmetic. Algae and moss can wear down your roofing materials, shorten the life of your shingles, and in some cases, lead to leaks or water damage. That’s why regular roof cleaning is important.

So, what’s the best way to clean your roof? It’s not a job for a pressure washer. In fact, using high-pressure water can damage your shingles and lead to costly repairs. Professional roof cleaners use a method called soft washing, which combines low-pressure water with specially formulated cleaning solutions that safely remove algae, moss, and dirt without harming your roof or surrounding landscaping.

A proper roof cleaning usually takes just a few hours and can dramatically improve the look and health of your roof. It also gives a roofing professional the chance to inspect for other potential issues like cracked flashing, loose shingles, or clogged gutters that could cause problems later.

It’s also important to pay attention to any warning signs that there might be a deeper issue. If you notice a musty smell in your attic, signs of water damage on your ceiling, or poor ventilation, there may be moisture getting inside. That could mean your roof needs more than just a cleaning. It might be time to check insulation, repair parts of the roofing structure, or even have the roof replaced. 

Having your roof inspected and cleaned at least once a year, especially in the spring or early summer, is a smart habit. It helps catch small issues before they become bigger problems, protects your home, and keeps your roof looking its best.

And remember, roof work can be dangerous. Between the height, the angle, and the risk of damaging your shingles, it’s not something you want to tackle on your own. Always call a licensed professional who has the right tools, training, and safety equipment to get the job done right.

Your roof is a big part of what keeps your home safe and dry. A little regular care goes a long way in keeping it that way.

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro.” All questions may be considered for publication. To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visit http://www.odonnellbros.com. Advice is for guidance only.

Add a Roof Inspection to Your Fall To-Do List

Your roof is one of the most critical parts of your home, yet many homeowners don’t think about it until there’s a problem. That’s why I recommend conducting a thorough roof inspection twice a year, ideally in the spring and fall. If there are any issues now, the cold and snow of winter could turn a small problem into a major headache.

Start with a Visual Check

Take a good look at your roof. Do the shingles appear to be in good shape? Is there any sagging or discoloration? Dark spots on the exterior or ceiling cracks and yellowing inside your home can be red flags signaling roof deterioration. Addressing these issues early can save you from costly repairs down the road.

Consider the Age of Your Roof

The lifespan of most roofs is around 20 years, but that can vary depending on the quality of installation, insulation, and ventilation. A well-installed roof with proper insulation and ventilation can last longer, but if your roof is approaching or has surpassed the 20-year mark, it’s time to consider a replacement. This is especially important if you’ve recently bought your home or are planning to purchase one. Knowing the age of the roof can help you plan for future maintenance or replacement.

Check for Shingle Damage

Are your shingles curling, splitting, or falling off? This kind of wear and tear often comes with age and exposure to the elements. Damaged shingles make your roof more vulnerable to leaks, which can lead to significant damage inside and outside your home. Look at where your downspouts deposit water—if you notice a lot of granules on the ground, it’s a sign that your shingles are deteriorating and may need to be replaced.

Watch for Moss and Mold

Moss or mold growth on your roof can be more than just a cosmetic issue. While it might be something a good cleaning can fix, it could also indicate trapped moisture and rotting plywood beneath the shingles. A professional inspection can help you determine if it’s a simple cleaning job or if more extensive repairs are needed.

Inspect Your Ceilings for Water Damage

If you notice yellowish-brown stains or cracks on your ceilings, it could be a sign of water damage coming from your roof. This is an issue you don’t want to ignore. Leaks tend to worsen over time, leading to more extensive and costly damage. Addressing them early can prevent a minor issue from becoming a major one.

Get a Professional Opinion

If you’re unsure about the condition of your roof, many roofing professionals offer free inspections. A qualified roofer can assess your roof’s current state and give you an estimate of how much longer it might last. One of the most common reasons roofs fail prematurely is poor ventilation and insulation, which can lead to early aging and rot. A good roofer will explain your options and help you make the best decision for your home.

If you need a roof inspection or any home improvement advice, don’t hesitate to reach out. A little preventative maintenance now can save you a lot of time, money, and stress later on.

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. For questions, email info@odonnellbros.com with the subject line “Ask the Pro.” Questions may be selected for publication. To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visitwww.odonnellbros.com. Advice is for guidance only.

Ceiling Cracks - A Cautionary Tale

After nearly 50 years in the remodeling business, I've seen my fair share of scary stuff inside people's houses. Some of these stories might hit home for those of you who put off fixing problems because you're afraid of what you might find. While big issues can be a pain and expensive, letting them go can lead to even bigger headaches down the road—and could even mess with your health.

One summer, I got a call from a woman in Bristol who said her roof was leaking. It was seemingly normal, except that it hadn’t rained in a month. I mentioned this to her, and she said, "I don't know where the water’s coming from, but my dining room ceiling just caved in."

I headed over to her house right away. Sure enough, there was a pile of sheetrock and plaster on her front lawn. Inside, the ceiling had completely collapsed, leaving a soggy mess all over her dining room.

I asked to see the bathroom on the second floor, but there wasn’t one. So, I climbed into the attic and was hit by a blast of intense heat. I also saw two air conditioning units running full blast in the dining room windows. The homeowner said she kept them on constantly because the top floor was so hot.

It didn’t take long to figure out why her ceiling fell in. The attic had no insulation or ventilation, turning it into an oven. The homeowner tried to cool things down by cranking the A/C, which created major condensation in the walls and ceiling.

When hot and cold air meet, they create moisture that seeps into plaster, sheetrock, and wood. That moisture leads to mold that literally eats away at the ceiling and walls. Her 1950s Cape Cod home, like many in our area of Connecticut, had poor insulation and ventilation, making it prone to rot. Ceiling cracks were the first sign of trouble. Instead of calling me then, her husband tried to cover them up with those 12x12 ceiling panels you see in doctor's offices. Nice try, but all it did was add another layer for moisture to soak into.

Here’s the bottom line: if your home has temperature issues, don’t ignore them. Deal with the humidity and moisture before it turns into major structural damage or worse. If that’s not enough to convince you, mold and mildew are big culprits behind asthma and breathing problems, especially for kids and the elderly. Is it worth risking your family’s health?

Bob O'Donnell is the owner of O'Donnell Bros, Inc., a Bristol-based home improvement company since 1975. Got a question for Bob? Email him at info@odonnellbros.com with "Ask the Pro" in the subject line. Your question might be featured in a future post. Need remodeling help? Call O'Donnell Bros, Inc. at (860) 589-5155 or visit www.odonnellbros.com. Remember, advice is just for guidance.