Mold on Your Roof: Causes and Solutions

Mold on Your Roof: Causes and Solutions

Mold. It’s not something you want to find on that leftover takeout you were excited about, and it’s certainly not something you’d want to find around your home! While attics and inner walls are mold’s usual hiding spaces, it also can turn up in other unexpected places—namely, your roof.

Tony’s Lifetime Exteriors, your Sauk Rapids roofing contractors, is here with the mold lowdown: how to spot it and what you can do about it.

Do I Have a Mold Problem?

Let’s back up for a minute. Though mold tends to have a slimy, otherworldly appearance, not everything green and fuzzy on your roof is, per se, a fungus. We know, we know—it’s not the most pleasant thing to learn that there’s more than one oozy thing that can grow wild among your shingles! But understanding the differences between the various threats your roof faces is critical to getting rid of them, as they all require different approaches and indicate different underlying issues.

So let’s take a look at a few common roof invaders and how they compare to mold…


Yep, this is similar to the stuff you’d find growing in a pond. Roof-growing algae is either black or green—similar to mold.

Algae can be damaging to your roof and could require professional attention, just like mold, but it lacks mold’s distinctive reeking stench and tends to congregate in your gutter installation due to standing water (though seeing it on your roof is by no means unheard of). It thus is a frequent indicator of a gutter problem.


It doesn’t smell, and it’s not slimy. In fact, it can be quite soft and pleasant to touch and can conjure images of a quaint little cottage. However, it’s not something you want taking up residence in your suburban home.

Where there’s moss there’s moisture, and that moisture is attractive to everything from mold to algae. If anything, it’s a sign that moisture management is currently an issue your roof is facing and that needs attending. It’s also a sign that you could be dealing with more serious issues later on.

Mold and Mildew

It’s slimy, stinky, potentially powdery, and comes in a variety of hues. Basically, if whatever is growing on your roof doesn’t fit into the other two categories—and most importantly, it stinks—it’s probably a bonafide fungi issue, and one that’s currently eating away at your roof thanks to moisture accumulation. Worst of all, it can worm its way into your home itself and cause a variety of health problems.

Getting Rid of Mold on the Roof 

You know it’s mold; It reeks like forgotten produce! But that’s a good thing—now you know how to tackle it, and what you’ll need to do afterwards to ensure the problem never happens again.

Pick the Right Roof Cleaner

The first step to getting rid of roof mold is, of course, cleaning off your roof. You’ve essentially got two options when it comes to cleaner: bleach-based and non-bleach based. Both have their pros and cons, and neither is inherently better than the other, though you’ll need to be careful to pick the right one for your needs.

  • Bleach-based cleaners are harsh, and best-suited for large-scale or stubborn infestations. They’re low-fuss, too. Just simply apply them to the roof and watch them go to work. However, you’ll need to wear respiratory protection while working with them, as bleach obviously is an irritant. You’ll also need to take care not to over-apply, as your garden certainly won’t appreciate it.
  • Chemical-based cleaners that don’t involve bleach tend to be on the less harsh side, and they might be a good fit for those who have young family members or pets. Thanks to their relative gentleness, they may also be a better fit for those who are inexperienced with roof cleaning.

One last note: When cleaning, don’t use a pressure washer! It’s a surefire way to shove water up underneath your shingles and cause more problems instead of fixing them.

Take Preventive Action

No matter what was growing on your roof, it’s a sign that something was up with your roofing or exterior, so you need to get professional roof repair pros out to your property ASAP.

Even though your mold issue now looks to be well-managed, mold has a way of sneaking into even the smallest cracks, and tackling it early is much easier than paying for an expensive remediation process. Luckily, you’ve found just the roofing company to help!

Tony’s Lifetime Exteriors: Let Us Put a Roof Over Your Head

Seamless gutters, roofing, vinyl siding installation, you name it—we’re versatile in our skill-set. Given that the moisture management issues that often result in mold are often multifaceted, we’re the perfect contractors to tackle your exterior unwelcome guests. Give our Sauk Rapids office a call today at 320-252-9086.


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