Moss or Algae Growth
Green moss or black algae streaks on your roof are common in humid climates. While algae is mostly cosmetic, moss can cause real damage if left untreated.
While not immediately critical, this should be addressed within a few weeks.
How to Identify This Problem
Look for these warning signs:
- Green fuzzy growth on shingles, especially north-facing slopes
- Black streaks running down the roof
- Dark staining that appears to spread over time
- Thick moss covering shingle surfaces
- Lifted or separated shingle edges under moss
- Curled or deteriorating shingles in affected areas
Common Causes
Shade and Moisture
Overhanging trees or north-facing slopes that stay damp and shaded create ideal conditions for moss and algae.
Humid Climate
Myrtle Beach humidity provides the moisture moss and algae need to thrive.
Organic Debris
Leaves, twigs, and other debris on the roof trap moisture and provide nutrients for growth.
Airborne Spores
Algae spreads through airborne spores - if neighbors have it, you may get it too.
Non-Algae-Resistant Shingles
Older shingles without copper or zinc granules are more susceptible to algae growth.
Poor Drainage
Areas where water pools or drains slowly stay damp longer, encouraging growth.
Solutions & Repairs
Professional Soft Washing
Professional RequiredLow-pressure cleaning with specialized solutions kills moss and algae without damaging shingles. Safer than pressure washing.
Zinc or Copper Strip Installation
Professional RequiredMetal strips installed near the ridge release algae-killing ions when it rains, preventing regrowth.
Tree Trimming
DIY PossibleCutting back overhanging branches increases sunlight and airflow, making conditions less favorable for growth.
Regular Debris Removal
DIY PossibleKeeping the roof clear of leaves and debris reduces moisture retention and nutrients for growth.
Algae-Resistant Shingle Replacement
Professional RequiredWhen re-roofing, choose shingles with copper or zinc granules that resist algae growth.
When to Call a Professional
Contact WeatherShield Roofing immediately if you notice:
- Moss is thick and lifting shingles
- You want professional cleaning without risking damage
- Growth has spread across large portions of the roof
- DIY cleaning attempts have not been effective
- You see signs of shingle damage under the growth
- You want to install preventive zinc or copper strips
Prevention Tips
- Trim trees to reduce shade and debris on roof
- Install zinc or copper strips near the ridge
- Clean gutters regularly to ensure proper drainage
- Remove debris promptly before it traps moisture
- Choose algae-resistant shingles for new roofs
- Address small patches before they spread
Frequently Asked Questions
Can I pressure wash moss off my roof?
Pressure washing is not recommended for asphalt shingles. The high pressure can blast away granules, void warranties, and cause more damage than the moss itself. Professional soft washing uses low pressure with cleaning solutions that kill growth without damaging shingles.
Will moss come back after cleaning?
Without preventive measures, moss and algae will eventually return, especially in shaded, humid areas. Installing zinc or copper strips, trimming overhanging trees, and choosing algae-resistant shingles for future replacement helps prevent regrowth.
Is roof algae harmful to my health?
Roof algae is not typically a health concern as it stays on exterior surfaces. However, heavy growth can reduce curb appeal and home value. In rare cases, spores could enter through open windows. The main concern is preventing shingle damage from associated moisture.
Get Expert Help
Our roofing experts can diagnose and fix this problem quickly.
(843) 877-5539Free InspectionEstimated Costs
*Estimates vary based on roof size, materials, and damage extent. Contact us for accurate pricing.
Our Response
- Emergency: Rapid response
- Inspections: Within 24-48 hours
- Free estimates provided
Need Help With Moss or Algae Growth?
WeatherShield Roofing provides expert diagnosis and repair services throughout Myrtle Beach and the Grand Strand.