How to clean stucco

Scroll to clean ↓

Short answer: Stucco gets cleaned with a soft wash, a cleaning solution applied at low pressure that kills mildew and algae and rinses away, never with a pressure washer on full blast. High pressure aimed at stucco can crack it or force water behind the surface, which is a much bigger problem than the green streaks you started with. A garden hose, a mild cleaner, and a soft brush can handle small spots, but a full house front usually calls for the right equipment and setup.

Why stucco is different from concrete

Concrete is dense and can take real pressure from a surface cleaner without damage. Stucco is a softer, more porous material, and the same pressure that lifts grime off a driveway can crack stucco or push water in behind it, which leads to problems well beyond a stain.

That is why the green streaks on the shaded side of a stucco wall need a different approach than the black marks on a driveway, even though both are just algae and mildew doing what algae and mildew do.

What causes the staining in the first place

Green streaking on the north or shaded side of a house is almost always mildew and algae, which thrive in Florida heat, humidity, and shade. It spreads over time and tends to come back faster in spots that stay damp longer, like under an overhang or next to landscaping that blocks airflow.

This is separate from the black streaks that show up on roofs, which come from a specific algae that feeds on the limestone in shingles rather than growing on stucco.

A safe approach for a small spot

For a small area, a garden hose, a soft-bristle brush, and a cleaner labeled safe for stucco or exterior siding, used exactly as its label directs, can lift light mildew without the risk that comes with high pressure. Test the cleaner on a small hidden section first, since stucco color and texture vary by house.

Wet down any nearby plants before you start and rinse them after, and keep pets away from the area until it dries. Never combine two different cleaning products together.

Why a full house is a bigger job

Cleaning an entire stucco exterior means working across every wall, corner, and eave at a consistent low pressure with a cleaning solution that has time to work before it is rinsed off. Missing a spot or using too much pressure in one section can leave an uneven result or, worse, crack the stucco.

A two-story home adds height and access that change how the job gets done safely, which is part of why this kind of full-exterior soft wash is usually left to equipment built for the job rather than a rented pressure washer.

What a professional soft wash includes

A house wash uses a soft wash on every material, including stucco, vinyl, block, and brick, so high pressure never touches the walls. The price is $279 typically in Volusia County, built from your home's square footage and story count.

Every job starts with a test stripe on the worst section, so you see the result before the rest of the house is washed, and plants get wet down before and rinsed after.

In Volusia County

Volusia County property records show 56% of homes were built before 1990. Older stucco has had more years to build up the green and black staining that shows up on the shaded side of a house. Puma's price list puts a typical house wash at $279.

Questions people ask

Can I pressure wash stucco myself?

High pressure on stucco risks cracking it or pushing water behind the surface, so it is not the right tool for this material. A soft wash at low pressure with a cleaning solution is the safer approach.

Why is the green staining worse on one side of my house?

Mildew and algae grow fastest where it stays shaded and damp, so the north side or spots under an overhang usually show more staining than a sunny wall.

How often does stucco need to be cleaned?

Most Florida houses do well on a wash every 6 to 12 months, with homes near the beach or under a lot of trees often needing it more often.

Will cleaning stucco damage the paint or texture?

A soft wash at low pressure is built to avoid that, which is the reason high pressure is avoided on stucco in the first place. A test stripe on your own house shows the result before the rest gets done.

Keep reading

House washing across Volusia →