How To Clean Dirty Exterior Stucco

How To Clean Dirty Exterior Stucco

Stucco is a common exterior building material used on many homes and commercial properties. Over time, exterior stucco can become dirty from environmental factors like rain, wind, pollution, mold, mildew and more. Knowing how to properly clean exterior stucco is important for maintaining your building’s appearance and preventing more severe issues like permanent staining or damage.

In this comprehensive guide, we will discuss steps and best practices for effectively cleaning dirty exterior stucco surfaces using pressure washing techniques and cleaning solutions.

What is Stucco?

Stucco is a durable, weather-resistant plaster commonly used for exterior siding. It’s composed of cement, sand, lime, and water, creating a robust yet porous surface. This porous nature makes stucco susceptible to stains and mold and mildew growth, necessitating regular cleaning.

Understanding Stucco and Typical Dirt Buildup

Stucco consists of an aggregate, cement-based coating troweled or sprayed onto a wire lath or masonry surface. It provides an attractive, durable and weather-resistant finish for exterior walls. However, stucco is porous and overtime dirt, grime, mold, mildew and environmental stains can accumulate, discoloring and staining the texture finish.

Typical dirt buildup on exterior stucco includes:

  • Dust, dirt and debris
  • Mold, mildew and algae growth
  • Water stains and mineral deposits
  • Pollution, vehicle exhaust and environmental stains
  • Leaf staining and organic matter

These types of dirt, if left for longer periods, can become more difficult to remove or even permanently stain or discolor the stucco. It’s important to regularly maintain and clean your exterior stucco to prevent permanent issues.

Gather the Right Stucco Cleaning Supplies

Cleaning exterior stucco effectively means having the proper supplies and tools. Key items you’ll need include:

Pressure Washer

Can you pressure wash stucco? A gas-powered pressure washer with 2,000 to 3,000 PSI is ideal for stucco cleaning. Pressure washers will supply the spraying pressure needed to lift dirt and debris without damaging the stucco. Adjustable tips and angles are helpful for targeting different areas.

Cleaning Solutions

Specialized heavy-duty stucco cleaners, mold/mildew removers or degreasers help break down and lift stubborn dirt and stains from textured stucco finishes. Always check product labels for exterior stucco application.

Scrub Brushes, Sponges and Scrapers

For concentrated scrubbing of heavily stained areas, various manual scrub brushes, sponges and even plastic scrapers can assist the cleaning process before rinsing.

Ladders, Scaffolding or Lifts

To safely reach all areas of taller walls or multi-story buildings, ladders, scaffolding or man lifts will likely be required. Use caution when working at elevated heights.

Personal Protective Equipment

Waterproof gloves, eye protection, rubber boots, face masks and head/ear protection keep the cleaning person safe, especially when using pressure washers.

How To Clean Dirty Exterior Stucco: 8 Steps

When ready to wash dirty exterior stucco, follow these key steps:

1. Inspect and Prepare the Stucco Surface

Closely inspect all stucco areas and identify heavily stained or especially dirty locations. Check for existing cracks, holes or other damage that may worsen during pressure washing. Prepare the area by clearing plants, materials or objects away from the building.

2. Apply Protective Coverings

Mask or cover nearby windows, doors, landscaping, outdoor furniture/features and vehicles that could get sprayed by the pressure washer. Help prevent overspray damage or unnecessary cleaning of other materials.

3. Test Your Cleaning Solutions

In a small, inconspicuous area, test applying your cleaning solutions and attempt washing with pressure Washer settings. Evaluate results to determine optimal spray angles, washing techniques and dwell times for chemicals. Adjust as needed.

4. Wet Stucco Surfaces with Water

Wet entire stucco surfaces lightly with a regular garden hose first. This helps prevent absorption of cleaning chemicals into the porous stucco. It’s also the start of softening and lifting dirt from the textured surface.

5. Apply Cleaning Solutions

Apply your cleaning chemicals liberally onto stucco surfaces using a pump sprayer according to label dilution rates. Let the solutions dwell for 5-10 minutes. Reapply as needed to keep surfaces wet. Scrub especially stained areas by hand during this time if needed.

6. Rinse with Pressure Washer

Rinse stucco surfaces using overlapping and consistent motions with pressure washer. Start rinsing from the bottom and work up methodically. Adjust spray nozzle angle and distance from wall to effectively target buildup. Avoid directing concentrated spray streams at one spot for too long.

7. Inspect and Spot Clean Missed Areas

Inspect entire stucco surface and look for any remaining dirty spots. Reapply cleaning solutions to missed areas, manually scrubbing as needed. Rinse spots thoroughly. Repeat cleaning steps in difficult regions until stucco appearance looks uniform.

8. Final Rinse and Dry Time

Provide a final light overall rinse of stucco surfaces to remove any last dirt, debris and cleaning chemical residue. Allow adequate drying time before touching up paint or caulk around wall edges.


  1. Can I use any cleaner for my stucco?
    • It’s best to use cleaners specifically designed for stucco or mild dish soap solutions to avoid damaging the surface.
  2. How often should I clean my stucco?
    • It depends on your local environment, but generally, a thorough cleaning every year or two is advisable.
  3. Can pressure washing damage stucco?
    • If done incorrectly, yes. Always use a low-pressure setting and avoid directing the spray into cracks.
  4. What should I do about cracks in my stucco?
    • Small cracks can be filled with exterior acrylic caulk. For larger issues, consult a professional.
  5. Is it necessary to rinse the stucco after applying a cleaning solution?
    • Yes, rinsing helps remove the loosened dirt and cleaning agents, preventing residue build-up.


Cleaning your exterior stucco is a task that requires careful consideration of the material’s characteristics and the right approach to avoid damage. By following these steps and maintaining a regular cleaning schedule, you can ensure that your stucco remains clean, intact, and visually appealing for years to come.

Properly pressure washing and cleaning exterior stucco takes some work but restores the attractive, uniform appearance of the textured finish. Follow these best practice steps for removing stubborn dirt, stains and debris. Always test chemicals and pressure washer settings first in inconspicuous areas to prevent damage. With the right methods, regular stucco maintenance cleaning can prevent permanent discoloration or more costly repairs down the road.

Contact Sullins Suds for professionally pressure washed stuccos!

Don’t Stop Here

More To Explore
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3. Detergent Selection
4. Test Spot
5. Even Application
6. Rinse Thoroughly
7. Allow to Dry

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