Stucco is a popular exterior siding material used on many homes and buildings. Over time, stucco can become dirty, stained, or discolored from environmental factors like rain, wind, pollution, and UV exposure. Knowing how to properly clean stucco can help restore its appearance and protect its surface. Here is a comprehensive guide on how to clean stucco surfaces.
What is Stucco?
Stucco refers to a type of exterior plaster coating applied in a wet mix directly onto masonry, concrete, brick, stone, or over wire lath attached to wood or metal frames. Traditional stucco consists of sand, Portland cement, water, and lime. Modern synthetic stuccos may also contain acrylic polymers, fibers, and other additives.
Stucco provides a durable, attractive finish for exterior walls while being water-resistant. The cement binder helps stucco last for decades, while the lime provides workability and flexibility. Synthetic acrylic stuccos offer enhanced durability and crack resistance.
Common types of stucco finishes include:
- Traditional three-coat stucco
- One-coat stucco systems
- EIFS – exterior insulation and finish systems
- Veneer plaster finishes
Reasons to Clean Stucco
Here are some of the main reasons you may want to clean your stucco surfaces:
Remove Dirt and Grime
Over time, wind, rain, pollution, and organic debris can dirty stucco surfaces. Cleaning helps restore the original appearance.
Eliminate Mold and Mildew
Mold, mildew, and algae may grow in shaded or damp areas. Cleaning sanitizes surfaces and removes staining.
Prepare for Repainting
Cleaning prepares stucco for repainting by removing chalky residue, efflorescence, and loose paint. This helps new paint adhere properly.
Improve Curb Appeal
Cleaning brightens up faded, stained stucco and enhances the curb appeal of your home.
Extend Service Life
Routine cleaning protects stucco from deterioration and helps maintain its functionality.
How to Clean Stucco
Cleaning stucco requires using the proper cleaning solutions and techniques to avoid damage. Here is a step-by-step guide:
1. Inspect and Prepare the Surface
Before cleaning, inspect the stucco for any cracks, damage, or deficiencies needing repair. Check for signs of mold or mildew growth. Identify particularly dirty or stained areas.
Clear plants, debris, and decorative items away from the wall base. Cover windows, doors, trim, and hardware to protect them from cleaning solutions.
2. Pre-wet the Stucco Surface
Use a garden hose to lightly pre-wet the entire stucco area you plan to clean. This prevents the surface from quickly absorbing the cleaning solutions.
3. Apply Cleaner and Let Dwell
Apply your chosen stucco cleaner onto the damp surface using a garden sprayer, brush, or roller. Let the cleaning solution dwell for 5-10 minutes so it can start interacting with the stucco. Avoid allowing cleaner to dry on the surface.
4. Pressure Wash the Surface
Use a pressure washer to rinse away the cleaning solution and lift off dirt and stains. Keep the nozzle 12-24 inches away and use a fan spray pattern under 1500 psi.
Pressure wash from the bottom up and follow with a clear water rinse. Avoid abrasive attachments and excessive pressure.
5. Allow the Stucco to Dry
Once clean, allow the surface to completely dry for 24-48 hours before sealing, painting, or applying any new finishes. The stucco needs to dry thoroughly or trapping moisture can cause problems.
6. Repair Any Damage
Inspect the clean stucco and make any needed crack repairs, patching, sealing, or recoating to maintain its functionality and appearance. Let repairs fully cure before painting or sealing.
Choosing a Stucco Cleaning Solution
The best stucco cleaner for the job depends on the type of stucco, the extent of dirt and staining, and your cleaning objectives:
General Purpose Cleaners
Household cleaners like liquid detergents or degreasers help remove light dirt. Limit scrubbing to avoid damage.
Alkaline Cleaners
For moderate grime, alkaline cleaners with ingredients like potassium hydroxide can cut through grease and oils. Rinse thoroughly.
Acidic Cleaners
For hard water deposits or efflorescence, acidic cleaners containing phosphoric or muriatic acid help dissolve mineral stains. Use with extreme caution.
Brighteners and Bleaches
Oxygen or chlorine bleach solutions help remove rust, mold, mildew stains, and discoloration. Rinse quickly to avoid oxidation.
Specialty Cleaners
For particularly stubborn staining, use heavy duty alkaline or acidic cleaners formulated specifically for masonry and stucco. Follow product instructions carefully.
When selecting any chemical cleaner, check that it is suitable and safe for the type of stucco finish on your home. Always spot test cleaners in an inconspicuous area first.
Tips for Cleaning Stucco
Follow these tips for safely and effectively cleaning stucco siding:
- Always pre-wet stucco before applying cleaners to prevent absorption.
- Use the lowest pressure possible to avoid surface damage.
- Rinse with clean water immediately after cleaning to neutralize and stop chemical activity.
- Avoid abrasive brushes, acidic cleaners on smooth finishes, and excessive scrubbing.
- Wear protective gear – gloves, eye protection, coveralls – when using chemicals.
- Work in manageable sections, starting from the bottom up.
- Let stucco dry completely before recoating, painting, or sealing.
- Dispose of waste properly according to cleaner label directions.
When to Hire a Professional
For large homes, two-story surfaces, or heavy soiling situations, consider hiring a professional stucco cleaning contractor. Their equipment, access, expertise, and waste disposal capabilities may be required.
Professionals also know the appropriate chemical solutions to use and specialized cleaning techniques for different stucco finishes. They can minimize the risks of surface damage that DIY cleaning sometimes causes.
Safety Precautions When Cleaning Stucco
Take the following safety precautions when working with stucco cleaning chemicals:
- Read all product labels and heed warnings. Follow usage directions exactly.
- Work in well-ventilated areas and wear protective equipment. Avoid skin and eye contact.
- Do not mix cleaners together – this can produce toxic fumes.
- Keep children and pets away from chemicals.
- Take care on ladders, scaffolding, or aerial lifts when working at heights.
- Contain waste properly and legally dispose of it. Do not wash chemicals into vegetation.
- Rinse stucco thoroughly with water after cleaning. Neutralize and remove any residue.
With the right methods and care, DIYers can safely and effectively clean stucco surfaces. Avoid damage by using proper chemical solutions, equipment, dwell times, rinsing, and surface preparation.
Frequently Asked Questions About Cleaning Stucco
How often should you clean stucco?
- Cleaning frequency depends on exposure and soiling. annually is typical for average conditions. Clean promptly after noticing heavy staining.
What kind of pressure washer is best for stucco?
- Electric pressure washers under 1500 psi are ideal for stucco. Gas models over 2000 psi risks damage. Use large fan spray tips and keep the nozzle at least 1 foot away.
Can I use bleach to clean my stucco?
- Yes, dilute bleach can help remove mold, mildew, and discoloration stains from stucco. Limit contact time and rinse thoroughly. Don’t use bleach cleaners frequently.
What removes efflorescence from stucco?
- White powdery efflorescence is best removed with diluted muriatic acid-based cleaners designed for masonry and concrete. Light efflorescence may come off with pressure washing.
How do you clean oil stains from stucco?
- Degreaser cleaning solutions help break down oil and grease stains on stucco. Apply degreaser, let it work for 5-10 minutes, then pressure wash off. Avoid abrasive scrubbing.
Can I use TSP to clean my textured stucco?
- Yes, trisodium phosphate (TSP) is an effective heavy-duty cleaner suitable for textured stucco finishes. Rinse thoroughly after use. Wear protective gear when handling TSP chemicals.
What do you use to clean painted stucco?
- Use only mild, pH-balanced cleaners like dish soap on painted stucco. Avoid abrasive scrubbing. Strong alkaline or acidic cleaners will damage the paint. Rinse thoroughly after cleaning.
How do I remove rust stains from stucco?
- Rust stains can be difficult to remove from stucco. Try a phosphoric acid-based rust remover before attempting other chemical cleaners. Limit contact time and rinse thoroughly.
Can a pressure washer damage stucco?
- Yes, pressure washers can damage stucco if not used properly. Keep pressure under 1500 psi and the nozzle at least 1 foot away. Do not use narrow high-pressure jets or zero-degree tips.
Conclusion
Regular cleaning helps maintain the appearance and extend the life of stucco building exteriors. While cleaning products and pressure washing can strip away dirt, oxidation, staining, and chalky deposits, care must be taken to avoid chemical or physical damage to the stucco surface.
With the right methods and precautions, homeowners can safely DIY clean stucco siding and restore its aesthetic appeal. However, for large homes or severe staining situations, hiring a professional may be advisable.
Through proper inspection, preparation, product selection, cleaning procedures and safety measures, stucco exteriors can be refreshed and protected through routine cleaning. Paying attention to manufacturer’s directions and testing products in inconspicuous areas first helps avoid undesirable results.