No, you should not use a pressure washer on your roof. Using a pressure washer on your roof may damage the material, instead, professionals opt to use a low pressure “soft wash” when cleaning roofs.
For some roofing materials such as metal, lower pressure washing is acceptable, but still take caution.
Double check what your roofing material is and then use the guide below to see if pressure washing is an appropriate option!
What Types Of Roofs Shouldn’t Be Pressure Washed?
| Roofing Material | No | With Caution |
| Asphalt Shingles | ✔ | |
| Wood Shingles and Shakes | ✔ | |
| Slate Roofing | ✔ | |
| Cedar Shake Roofs | ✔ | |
| Composite Roofing | ✔ | |
| Clay and Concrete Tile Roofing | ✔ | |
| PVC and TPO Roofing | ✔ | |
| EPDM Roofing | ✔ | |
| Green Roofs (with special techniques) | ✔ | |
| Metal Roofing | ✔ |
Asphalt Shingles
With 80% of homes in America using this material, asphalt shingles are one of the most common roofing materials, but they should never be pressure washed. The intense water pressure can strip away the protective granules that shield shingles from the sun’s UV rays, weakening their ability to protect the home. Additionally, pressure washing can break the adhesive bonds between shingles, increasing the risk of leaks and reducing the roof’s lifespan. Instead, soft washing with specialized cleaning solutions is a much safer alternative.
Wood Shingles and Shakes
Wood shingles and shakes are highly vulnerable to damage from pressure washing. The powerful stream of water can cause splintering, remove natural oils that preserve the wood, and create openings where mold and mildew can grow. These issues can accelerate the deterioration of the roof, leading to costly repairs or premature replacement. A gentle soft washing method or a professional roof cleaning service is the best way to clean wood roofs without causing harm.
Slate Roofing
Slate is a durable and long-lasting roofing material, but it is not immune to damage from high-pressure water. Pressure washing can lead to cracks, erosion, or even breakage of slate tiles, which are expensive and difficult to replace. Because slate roofs are designed to last for decades, homeowners should avoid pressure washing and instead use soft cleaning methods to preserve their integrity.
Cedar Shake Roofs
Cedar shake roofs, like other wood roofing options, should never be pressure washed. The force of the water can wash away essential natural oils, causing the wood to dry out and crack over time. Additionally, pressure washing can damage the seals and waterproofing treatments, leaving the roof vulnerable to moisture infiltration. To maintain the longevity and appearance of a cedar shake roof, soft washing or professional roof treatment is recommended.
Composite Roofing
Composite roofing, made from a blend of materials like asphalt, fiberglass, and recycled plastics, is designed to be durable and low maintenance. However, pressure washing is not recommended for composite roofs, as the high-pressure water can strip away the protective outer layer, loosen the granules, and weaken the bonding agents that hold the shingles together. Over time, this can lead to premature wear, leaks, and reduced lifespan.
Instead of pressure washing, a soft washing method using low-pressure water and a gentle cleaning solution is the best way to clean a composite roof. This approach removes dirt, algae, and mildew without causing structural damage. For long-term maintenance, homeowners should also ensure proper ventilation and gutter cleaning to prevent moisture buildup and moss growth on their composite roofing.
What Types Of Roofs Can Be Pressure Washed?
While pressure washing is generally not recommended for many roofing materials due to the risk of damage, some roofs can withstand it when done correctly using the right techniques and pressure settings. Below are the types of roofs that can be pressure washed with proper precautions.
Metal Roofing
Metal roofs are among the most durable roofing materials and can handle pressure washing better than most. They are resistant to moisture and can withstand a controlled amount of pressure without significant damage. However, using excessive pressure can dent the panels, strip away protective coatings, or damage sealants. The best approach is to use a low to medium-pressure setting and a wide spray nozzle to prevent concentrated water force from harming the surface. A biodegradable cleaning solution can also help loosen dirt, moss, and algae without excessive pressure.
Clay and Concrete Tile Roofing
Clay and concrete tiles are relatively durable and can be pressure washed, but only with extreme caution. Too much pressure can crack or break the tiles, while incorrect washing techniques may loosen the mortar holding them in place. If pressure washing is necessary, it should be done at a low-pressure setting with a wide spray pattern to minimize the risk of damage. It’s also advisable to spray at a downward angle to prevent water from getting under the tiles and causing leaks.
TPO Roofing
Thermoplastic Olefin (TPO) roofing is a durable, energy-efficient roofing material commonly used on commercial and flat-roof structures. While TPO roofs are designed to withstand exposure to the elements, they should not be pressure washed using high-pressure settings. The force of pressure washing can cause seam separation, membrane punctures, or damage to the protective coating, leading to leaks and reducing the roof’s lifespan. Additionally, excessive water pressure can force water into areas where it should not go, potentially compromising the roof’s insulation and underlying structure.
For cleaning TPO roofs, a low-pressure wash or soft washing method with mild detergents is the safest approach. A combination of non-abrasive cleaning solutions and a gentle scrub brush can effectively remove dirt, algae, and stains without damaging the membrane. Regular maintenance and professional roof inspections are also recommended to keep a TPO roof in top condition while avoiding unnecessary wear and tear.
The Risks of Pressure Washing a Roof
While pressure washing is effective for certain outdoor surfaces like driveways and sidewalks, using it on a roof poses several risks:
Structural Damage: High-pressure water can loosen shingles, break tiles, or dent metal roofing, leading to costly repairs.
Water Intrusion: Improper technique can force water under shingles or tiles, potentially causing leaks, mold growth, and structural damage inside the home.
Erosion of Protective Layers: Many roofing materials have coatings or granules that provide protection from the elements. Pressure washing can strip away these protective layers, leaving the roof vulnerable to UV damage and weathering.
Personal Safety Hazards: Climbing onto a roof to pressure wash increases the risk of slips and falls. Wet roofs, especially those covered in moss or algae, can become extremely slippery, posing a danger to homeowners attempting DIY cleaning.
Safer Alternatives to Pressure Washing
Instead of pressure washing, there are alternative methods that can effectively clean a roof without causing damage:
Soft Washing
Soft washing is a gentle yet effective method of cleaning roofs. It uses a low-pressure spray combined with specialized cleaning solutions to break down dirt, algae, and moss. This method is safe for most roofing materials and helps maintain their longevity.
Leaf Blowers and Gentle Hosing
For roofs with minimal debris, a leaf blower or a garden hose with mild water pressure can be effective in removing leaves, twigs, and loose dirt. This method works well for metal, slate, and asphalt shingle roofs without the risks associated with high-pressure washing.
Chemical Treatments
Certain environmentally friendly cleaning solutions can be applied to the roof to break down algae and moss growth. These treatments often require minimal scrubbing or rinsing, making them a safer option for delicate roofing materials.
Manual Cleaning with a Soft Brush
For tougher stains, a soft brush with a long handle can be used to gently scrub problem areas. This method provides more control over the cleaning process and minimizes the risk of damaging the roofing material.
Safety Considerations When Cleaning a Roof
Regardless of the cleaning method chosen, safety should always be a top priority:
- Wear Proper Safety Gear: Use non-slip boots, protective eyewear, and gloves to minimize risks.
- Use a Sturdy Ladder: Ensure that the ladder is stable and placed on a solid surface before climbing.
- Work with a Partner: Having someone nearby can provide assistance in case of an emergency.
- Hire a Professional: If the roof requires extensive cleaning, it is best to hire a professional roofing contractor who has the experience and equipment to do the job safely and effectively.
Final Thoughts
For 80% of Americans, you should not pressure wash your roof. If your roof is made of certain materials such as metal or tile, pressure washers can be used, but with caution.
If you need your roof pressure washed, it’s best to call a professional like the team at Vesta Property Pro. We have the experience and equipment to clean your roof safely and effectively.
Reach out to us today for a free quote on your next roof cleaning!
