Written by Sam on November 26, 2025. Posted in Roof Care

Safe and Effective Methods to Remove Moss & Algae

1. Manual Brushing & Gentle Scraping

Manual removal is controlled and low-risk when done carefully.

Use a soft-bristle brush or plastic scraper.
Work from the top of the roof downward to avoid forcing debris beneath tiles.
Avoid wire brushes and aggressive tools that remove protective coatings.

2. Low-Pressure Rinsing / Soft Washing

Soft washing avoids the damage that high-pressure jet washers can cause.

Use a garden hose or a professional low-pressure system for rinsing.
Rinse gently to remove loose material without driving water under tiles.
If required, use a roof-safe cleaning solution and follow the product instructions.

3. Biocidal or Moss-Killing Treatments

For stubborn or recurring growth, a targeted treatment can help prevent regrowth.

Apply after removing the bulk of moss for best penetration of the treatment.
Protect surrounding plants, gutters and drainage from runoff.
Follow manufacturer instructions and safety guidelines when using chemical treatments.

Prevention — Make It Less Likely to Come Back

Trim overhanging trees to increase sunlight and airflow across the roof.

Keep gutters clean to prevent moisture buildup along roof edges.

Install zinc or copper strips near the roof ridge; ions released by these metals can help inhibit moss and algae.

Schedule periodic roof inspections to catch early growth before it becomes a problem.

What to Avoid

Some common approaches do more harm than good:

Do not use a pressure washer on tiled or slate roofs — high pressure can crack tiles, strip coatings and force water under the roof covering.

Avoid wire brushes which can permanently scratch or erode tile surfaces.

Do not apply chemicals carelessly — uncontrolled runoff can damage plants and drainage systems.

Don’t work without proper safety gear — roofs are slippery and falls cause serious injury.

When to Call a Professional

DIY cleaning is possible for small, straightforward jobs, but professional help is often the safer and more effective option when:

The roof is steep, wet, fragile or difficult to access.

Moss or algae cover a large area or are deeply established.

You have an older, heritage or brittle roof where damage risk is higher.

You want a long-term solution that includes removal, treatment and prevention measures.

Professionals bring the right equipment, methods and safety precautions to clean without damaging your roof and to reduce the chances of regrowth.

Final Thoughts

Moss and algae affect more than appearance — they trap moisture, accelerate wear and can lead to costly repairs if ignored. Choose gentle, roof-appropriate cleaning methods, take preventative steps and call a professional when the job is beyond a simple DIY task. With the right care, your roof will last longer and keep protecting your home effectively.