Mold, Mildew or Algae? What's Really Growing in Your Delaware Beach Home?

Quick Answer

Is it mold, mildew or algae? Homes in Rehoboth, Lewes, Bethany Beach, Milton and throughout Sussex County deal with plenty of conditions that help make all three possible. Even though they are very different from each other, humidity, rain, shade, trees, seasonal temperature changes and our proximity to the coast can contribute to all of them turning siding, roofs, decks, fences and other exterior surfaces into places where unwanted growth can do more than just look bad. Depending on what it is and where it's growing, it can aggravate allergies, create slippery walking surfaces and signal the kind of persistent moisture that can eventually contribute to deterioration, particularly on wood. 

The good news is you don't need to become a backyard biologist to keep your home clean and your environment safe. You can just call us!

Because what's growing and what it’s growing on matter, we treat and clean each for what they are. And this rarely, if ever, means power washing with just more pressure, but instead balancing the force, temperature and environmentally friendly chemical make-up of the water to give your home a truly deep and safe cleaning.

So, Is It Mold or Mildew?

Let's start with two words that are often used as though they're completely different things.

• Mold.
• Mildew.

Technically, mildew is generally a name used for certain kinds of mold or fungal growth. So, while people commonly separate the two, they're more closely related than the terminology makes them sound.

For a homeowner standing in the yard looking at a dirty house, the scientific distinction probably isn't the most important part anyway.

The important part is this:

Something is growing where you don't want it.

And there's usually a reason it's there.

Mold and similar fungal growth need favorable conditions, particularly moisture. Exterior surfaces that remain damp, receive limited sunlight, sit beneath trees, or collect organic material can provide those conditions.

That's why one side of your house can look perfectly clean while another starts looking like it belongs to somebody else.

And Then There's Algae

That green discoloration spreading across your siding may not be mold at all.

It may be algae.

-Unlike mold and mildew, algae isn't a fungus. But from the homeowner's perspective, it creates a very similar problem:

-Your house is slowly changing color.

-You may notice it first on shaded siding, fencing, roofing or other areas where moisture hangs around longer.

And because the change happens gradually, you may not realize how much the appearance has changed until you compare the dirty area with one that's still clean.

That's one of the funny things about exterior buildup.

You see your house every day.

Sometimes everyone else notices it before you do.

Why Sussex County Homes Can Be Great Places for Things to Grow

Living near the Delaware beaches has its advantages. Unfortunately, mold, mildew and algae seem to appreciate some of those advantages too.

Homes throughout Rehoboth, Lewes, Bethany Beach and Milton experience a combination of environmental conditions that can encourage exterior buildup.

• Humidity brings moisture.
• Rain wets exterior surfaces.
• Shade slows drying.
• Trees create shade while also dropping leaves, pollen and other organic material.
• Wind moves dirt and debris into places you'd never intentionally put it.
• And seasonal weather keeps changing the conditions your home's exterior has to deal with.

A home surrounded by trees in Lewes may develop very different problems than a house exposed to more direct sun in Bethany Beach.

Even two sides of the same house can behave differently.

That's why exterior cleaning isn't simply about the town you live in.

It's about the environment immediately surrounding your home.

Shade Can Change Everything

Walk around your house sometime and look closely at each side.

There's a good chance they don't all look the same.

One may get strong afternoon sun.

Another may spend most of the day in shade.

One may sit beneath mature trees.

Another may be exposed to wind.

Those small differences create different conditions.

Sunlight and airflow help wet surfaces dry.

Shaded areas can stay damp longer.

And where moisture remains, biological growth gets more opportunity to establish itself.

That's why the north side of a home, heavily wooded areas and places behind shrubs or landscaping often seem to get dirty faster.

It's also why cleaning schedules shouldn't automatically be identical for every house—or even every surface on the same house.

Cleaning What's Growing Without Damaging What's Underneath

This is where our earlier discussion about power washing, pressure washing and SoftWash becomes important.

If something is growing on your siding, the obvious reaction might be:

• Hit it harder.
• More pressure.
• Problem solved.

Except the growth isn't the only thing you're hitting.

You're also applying that pressure to vinyl, aluminum, brick, cedar, painted surfaces, window seals and whatever else happens to be underneath it.

That's why Sussex Pro Wash generally favors a SoftWash approach using the appropriate combination of professional cleaning solutions, water volume and controlled pressure, with heated water when the job calls for it.

The goal isn't to overpower the dirt.

It's to properly clean the surface.

Those aren't always the same thing.

Cleaning Is About More Than What You Can See

This is also why cleaning chemistry matters.

• Exterior buildup isn't all identical.
• Ordinary dirt isn't algae.
• Algae isn't mold.
• Pollen isn't mildew.
• And insect residue isn't any of them.

If different contaminants behave differently, it makes little sense to assume they should all be cleaned exactly the same way.

Properly selected cleaning solutions help break down the particular buildup being removed so water and pressure don't have to do all the work.

That means less unnecessary force on the surface while still delivering a thorough clean.

It's the same philosophy we've talked about before:

Use the cleaning method that matches the job.

Why Waiting Usually Doesn't Help

Mold, mildew and algae aren't likely to improve because you give them another month.

When conditions remain favorable, exterior growth can continue spreading and become increasingly noticeable.

There's an appearance issue, certainly.

But there's also a maintenance issue.

The longer exterior buildup remains, the longer moisture, dirt and organic material remain in contact with surfaces you're paying to protect.

Regular exterior cleaning interrupts that cycle.

Instead of waiting until the house looks dirty enough that something has to be done, maintenance lets you deal with buildup before it becomes the first thing you notice when you pull into the driveway.

That's easier on the house.

And usually easier on you.

So, Do You Need to Know Exactly What It Is?

Probably not.

At least not before you call us.

You don't need to stand in the yard wondering whether the green stuff on your siding belongs to the plant kingdom or the fungus kingdom.

That's our problem.

What matters to you is that something is growing on your house that shouldn't be there, and you want it removed without damaging what's underneath.

That's where experience matters.

• Identify the condition.
• Understand the surface.
• Choose the cleaning method.
• Then clean it properly.

Simple enough from your side of the driveway.

The Bottom Line

Mold, mildew and algae may get lumped together in everyday conversation, but they aren't all the same.

And your home's exterior isn't one uniform surface either.

• Vinyl siding isn't cedar.
• Brick isn't roofing.
• Wood isn't aluminum.
• Sun-drenched siding doesn't experience the same conditions as a shaded wall beneath mature trees.

The best exterior cleaning starts by recognizing those differences.

At Sussex Pro Wash, our goal isn't to attack every stain with the highest pressure available. It's to understand what we're cleaning, what we're cleaning it from, and choose the process that delivers the best result while protecting your home.

Because when something unwanted starts growing on your house, you don't need to know its scientific name.

You just need to know who knows how to get rid of it.

And speaking of things growing where they shouldn't...

If you've ever looked up and wondered what those dark streaks, green patches or mossy areas are doing to your roof, that's another story entirely.

And it's one we'll get to next.