The green stuff growing on your house in Florida is almost always algae. It grows where a wall stays damp and shaded. Luckily, a soft wash removes it safely, and a few small habits slow it from coming back.
At Top Down Exterior Cleaning, we have washed homes in Lakeland and Polk County since 2010. So we see green walls every week. Below, we explain what it is, why it picked your house, and how to get rid of it.
Is the Green Stuff on My House Algae, Mold, or Mildew?
A thin green film is usually algae. However, Florida walls can grow more than one thing at a time. Here is a quick way to tell them apart:
- Algae. A flat green film or green streaks. It often feels slick when wet.
- Mildew. A powdery layer that looks gray, black, or even pink.
- Mold. Black, brown, or dark green blotches in spots that stay wet.
- Moss. A thick, spongy green layer you can pinch.
- Lichen. Crusty green or gray circles that cling tight to the wall.
Often, you will find two or three of these on the same wall. For example, green algae may cover the stucco while black mildew dots the soffit above it. The good news is that one soft wash treats them all.
Why Is Green Stuff Growing on My House in Florida?
Green stuff grows on your house because the wall stays damp. Florida adds heat and humidity, and that mix helps algae spread fast. In fact, the U.S. Environmental Protection Agency says moisture control is the key to mold control. The same idea holds for the algae and mildew on your walls.
So look for what keeps your wall wet. These are the usual causes we find around Lakeland:
- Shade. North walls and walls under big trees dry slowly.
- Sprinklers. Heads that spray the house soak the same spot every morning.
- Shrubs. Plants pressed against the wall block sun and air.
- Gutters. Clogged gutters spill water down the wall.
- Rain splash. Dirt and water bounce up onto the bottom few feet of the house.
That is why one side of your home may look green while the sunny side looks fine.
Is the Green Stuff on My House Harmful?
Green algae on an outside wall is mainly a looks and upkeep problem. It will not eat through stucco overnight. Still, you should not leave it for years.
First, growth holds moisture against your paint. Next, it spreads to soffits, trim, screens, and walkways. Then the stains set deeper, and the job takes more work to clean. As a result, a small green patch this year can become a whole wall next year. Also, the same algae makes steps and walkways slick when wet.
How Do You Get the Green Stuff Off Your House Safely?
The safe way to get green stuff off your house is a soft wash. A soft wash uses cleaner to kill the growth, and then low pressure rinses it away. Therefore, your paint and stucco stay in good shape.
Our house washing in Lakeland, FL works like this:
- First, we apply the cleaner. We use detergents made for siding and stucco. They break down algae, mold, mildew, pollen, and dirt at the source.
- Next, we let it work. The cleaner lifts the green film, so we don’t need to blast it.
- Then, we rinse. We use plenty of water at low pressure. We only add pressure where a surface can safely handle it.
We wash stucco, vinyl siding, fiber cement siding, painted block, and brick. We also clean soffits, fascia, trim, and exterior doors. Plus, we offer an optional sealant that helps a wash last longer before the green returns.
Can You Pressure Wash the Green Stuff Off Stucco or Siding?
You can, but you should not. High pressure can chip paint and scar stucco. Also, a stream aimed upward can push water behind siding panels.
On top of that, pressure alone leaves some growth alive. So the green comes back sooner. Cleaner does a better job because it kills what the water can’t reach.
Can You Just Paint Over the Green Stuff on Your House?
No, you should not paint over the green stuff on your house. Paint does not bond well over algae, mold, mildew, or dirt. As a result, the new coat can peel, and the stains can show through.
Instead, wash the house first. Most painters ask for it. Then let the walls dry before anyone opens a paint can. Sometimes a good wash shows that the paint underneath still looks fine.
How Do You Keep Green Stuff From Growing Back on Your House?
You keep green stuff away by keeping your walls dry. No wash lasts forever in Florida, because the heat and humidity never quit. However, these habits buy you more time:
- Trim shrubs and branches. Leave a gap so sun and air reach the wall.
- Aim your sprinklers. Point the heads at the lawn and away from the house.
- Clear your gutters. Clean gutters carry water away from the walls.
- Watch the shady side. Check your north wall a few times a year.
- Wash early. Book a cleaning when you first see a green tint.
In short, a clean wall and less moisture give algae a much harder start.
Ready to Get the Green Stuff Off Your House?
You don’t have to live with a green wall. Top Down is family owned and insured, and we have served Lakeland since 2010. We have also earned the Angie’s List Super Service Award five times.
Contact Top Down Exterior Cleaning today for a free estimate. You can also call us at (863) 904-8956. We will come out, look at your home, and give you a clear price.
