The Best Safe and Effective Methods For Cleaning Moss on Your Roof

Moss is a small, green, plant-like organism that thrives in damp, shaded environments. While it may add a bit of rustic charm at first glance, moss growing on your roof can spell trouble. Roof moss can compromise shingles, cause mould growth, and lead to wood rot issues that are not only unsightly but often costly to repair.

At Remember Me Roofing, we’ve seen countless homeowners in Ottawa and across Canada face recurring moss problems. That’s why it’s crucial to understand what causes moss, how to remove it safely, and, most importantly, how to prevent it from returning.

Why Moss Is a Problem on Roofs

Moss clings tenaciously to roof surfaces, pushing its roots, or rhizoids, into and under shingles. Over time, this leads to several common problems:

• Roof shingle damage: Lifting, cracking, or curling shingles can allow water to get in.
• Moisture retention: Moss traps water, increasing the risk of mould, mildew, and wood rot.
• Structural compromise: Repeated water seepage can damage roofing underlayment and sheathing.
• Shortened roof lifespan: Roofs covered in moss often require premature replacement due to its detrimental effects on the roof’s structure.

In short, moss is a threat to your roof’s longevity, your home’s structural integrity, and your budget.

Identifying Moss on Your Roof

Before tackling removal, you need to know what you’re dealing with. Moss is identifiable by its:

• Green, fuzzy appearance, usually seen in patches or clumps.
• Distinct texture, differentiating it from slimy algae or flat lichens.
• Preference for shaded, damp spots, often on north-facing slopes, overhangs, or roofs near trees.

Moss can thrive on various roofing materials, including asphalt shingles, wood shakes, tile, and even some metal roofs. Identifying it early is key. At Remember Me Roofing, we often see customers confuse moss with harmless algae, but that fuzzy texture is a clear giveaway.

If you’re unsure, a professional roofer can help confirm whether it’s indeed moss and guide you on the best removal method.

Preparing for Moss Removal

Preparation is essential to protect both your home and health. Follow these steps before you climb on the ladder to inspect the moss:

• Cover plants and landscaping: Chemical runoff or moss debris can damage delicate plants and landscaping. Cover garden beds or shrubs near the house with plastic sheeting.
• Clear loose debris: Remove leaves, twigs, and dirt to expose moss completely. This ensures cleaning solutions can reach all affected shingle areas.

At Remember Me Roofing, our professionals know the importance of protective measures before getting started with moss removal. Here’s a look at our initial process:

• Wear protective gear: We ensure safety with rubber gloves, non-slip footwear, safety glasses, and a dust mask. Dealing with organic matter and cleaning chemicals warrants proper protection.
• Choose safe access equipment: We only use sturdy ladders or, in some cases, scaffolding. Roof work involves serious risk, and our team never compromises on safety. 
• Pre-wet the moss: Lightly misting the moss with a garden hose can make it easier to remove and reduce airborne debris. We know the right amount of pressure to apply to get this step done right.

Safety Precautions When Removing Moss From Your Roof

Removing moss improperly can cause more harm than good. Like any roofing project, whether it’s a repair, replacement, or inspection, we know the right tools to get the job done. Let’s look at how we approach moss removal:

• Use soft-bristle brushes: Scrubbing aggressively can strip granules from shingles or scratch tiles, thereby reducing the roof’s lifespan.
• Avoid pressure washers at all costs: High-pressure water jets can blast shingles apart, tear off granules, and drive water under the roofing membrane, creating hidden damage and leaks.
• Check roof pitch and slope: Steeper roofs require harnesses or professional experience. When you call Remember Me Roofing, you get both.
• Follow chemical safety guidelines: If a commercial moss remover is needed, we stick to the manufacturer’s instructions.

Step‑by‑Step Moss Removal

We’ve set the scene for proper roof moss removal preparation. It’s time we get to the right steps to get the job done.

Please note: While you can remove moss from your roof yourself, it is increasingly difficult and dangerous. We recommend you leave it to the pros (like us).

1. Loosen the loose moss: Gently brushing the moss downward toward the gutter using a soft-bristle or long-handled scrub brush, it’s best to work in the same direction as the shingles to avoid undercutting.
2. Apply a moss-removal solution: The solution should be tailored to your roof material—commercial roof-safe moss killers are ideal.
   • Spray bottles or pump sprayers ensure complete coverage of affected areas.
   • Contact time should be at least 15–20 minutes (or as labelled) for it to kill the moss.
   • Test patch as needed to check that there will be no adverse effects on shingles before full-scale application.
3. Let the solution work: Let it sit for the recommended duration. Moss may begin to turn darker or brownish, proof that it’s working. Avoid rinsing prematurely.
4. Rinse gently: Use a garden hose set to light spray to rinse moss and residual solution down toward the eaves. Move slowly to avoid missing debris.
5. Repeat as needed: If patches remain, reapply the solution and gently scrub again. Complete eradication may take 2–3 passes.
6. Final inspection: Once dry, inspect the roof surface. Look for stray moss or black streaks—clear them before concluding the job.

Cleaning Solutions: Commercial vs. Homemade

Choosing the right moss-killing solution depends on your priorities, budget, and the type of roof.

• Commercial products: Roof-safe moss killers, such as Wet & Forget, BioAdvance, or 30 Seconds, are specifically formulated for use on asphalt shingles, tile, and metal. They’re biodegradable and easy to apply.
  • Select a product labelled for roofing materials
  • Check for eco-friendliness if runoff is near plants/water
  • Read and follow all safety precautions
• Homemade solutions: You can remove moss with standard household products:
  • Diluted bleach solution (1 part bleach to 10 parts water).
    Warning: Can harm plants and discolour shingles if not rinsed promptly.
  • White vinegar (5%): spray, let sit, then rinse gently.
  • Baking soda paste: Apply a one-cup baking soda paste made with enough water to form a paste, let it sit for a few minutes, then scrub it off.

While cost-effective, homemade remedies can be riskier. Always test a small patch and rinse thoroughly to minimize damage.

Prevention: Stop Moss Before It Starts

After cleaning, prevention is the best long-term strategy:

• Trim overhanging branches to increase sunshine and airflow.
• Maintain clean gutters to prevent clogged water and debris buildup.
• Inspect for pooling water and fix any low spots.
• Install moss-inhibiting strips
  • Proper positioning beneath shingles near the ridge
  • Manufacturer-approved fasteners
  • Replacement every 15–20 years as materials wear
• Use roof-friendly coatings: Some algae-resistant or anti-moss roof coatings help prevent moss, but always verify compatibility with your material.
• Schedule routine maintenance: Clear debris from roofs and gutters at least twice a year to prevent clogs and ensure proper drainage. Contact Remember Me Roofing to conduct seasonal roof inspections, especially in spring and fall.

Installing Deterrents: Zinc & Copper Strips

Zinc and copper roof strips are powerful moss-control tools:

• When rain falls on the strip, tiny metal ions are washed over the roof.
• These ions suppress the growth of moss and algae.
• Strips should be installed just below the roof ridge for optimal coverage.

Key advantages:

• Minimal visual impact
• Long-lasting lifespan
• Passive, low-maintenance solution

Professional installation ensures optimal placement and effective performance, particularly in areas with steep slopes or limited access.

• We select high-quality metal strips or shingles featuring embedded metal granules.
• Each strip is fastened securely beneath the ridge cap.
• Using flashing tape, we protect metal from direct sunlight.
• During roof inspections, we look for signs of corrosion.

Maintenance & Regular Inspection

Ongoing care is essential for a moss-free roof. Here’s a recommended maintenance plan:

• Seasonal inspections (Spring and Fall)
  • Look for any moss regrowth or black streaks
  • Check for damaged shingles, leaks, or wear
  • Clean gutters and downspouts
• Mid-Year Maintenance
  • Trim nearby trees and brush
  • Rinse passive deterrents to wash away residue
  • Spot-treat stubborn moss patches
• Annual Professional Roof Inspection
  • Pressure-test the valley flashing
  • Replace worn shingles
  • Repair ventilation or insulation issues

With regular upkeep, homeowners can often extend a roof’s lifespan close to or beyond the manufacturer’s expectations.

Let Remember Me Roofing Handle It

Tired of dealing with moss on your roof? Let the experts at Remember Me Roofing take care of it—safely and effectively. From detailed inspections and professional moss removal to long-term prevention with zinc or copper strips, we offer complete solutions tailored to your roof type. We also offer gutter cleaning, shingle repair, and maintenance packages to keep your roof moss-free throughout the year.

Call us today at 613-854-7663 or request your free estimate to protect your home and extend the lifespan of your roof.

Frequently Asked Questions

Can I walk on my roof to clean moss?

Walking on a roof can be dangerous, and even minor slips can lead to serious injuries. On steep or damaged roofs, it’s best to hire a professional who is trained to work at heights and assess roofing conditions safely.

How soon does moss return after cleaning?

Without any preventative measures, moss can begin to regrow in as little as 6–12 months, especially in damp, shaded environments. Installing zinc or copper strips, maintaining clean gutters, and ensuring adequate sunlight can help keep your roof moss-free for several years.

Are roof-safe moss killers environmentally friendly?

Many roof-safe moss killers are biodegradable and designed to minimize harm to plants, pets, and surrounding landscaping. However, it’s crucial to read product labels carefully and follow application guidelines. For homeowners near gardens or water sources, choosing eco-conscious solutions is especially important.

Is bleach effective for moss removal?

Bleach can kill moss when diluted properly, typically using one part bleach to ten parts water. However, it must be used cautiously. Bleach can harm roofing materials, damage nearby vegetation, and pose risks if not handled with proper protective gear. Always rinse thoroughly after application and avoid use near sensitive areas.