A roof is more than just protection from rain, snow, and wind – it’s also a major part of your home’s curb appeal. Asphalt shingles are among the most popular roofing materials in Canada because they’re durable and affordable. Over time, however, moss, lichen, mold, and dirt can build up on the surface. These not only make your roof look neglected but can also shorten its lifespan.
Proper cleaning helps preserve your shingles, maintain your home’s appearance, and prevent costly repairs. Below is a detailed guide tailored to Canadian climates.
Why Regular Roof Cleaning Matters
Preventing damage. Moss and lichen trap moisture, which can cause shingles to deteriorate prematurely.
Energy efficiency. A dirty roof absorbs more heat in the summer, increasing strain on your air conditioner.
Curb appeal. A clean roof makes your home look well-maintained, which is especially valuable if you plan to sell.
Longevity. Regular cleaning can extend the life of your shingles by 5–10 years.
Tools and Materials You’ll Need
Before starting, gather everything necessary:
- A ladder with safety stabilizers
- A soft-bristle brush with a long handle or telescoping pole
- A garden sprayer
- Protective gloves and safety goggles
- A garden hose (avoid pressure washers, which can damage shingles)
- A roof-cleaning solution (store-bought or homemade)
Popular cleaning solutions include:
- Bleach and water mix (1 part bleach to 3 parts water) – very effective against moss and mold.
- Oxygen bleach – a gentler, eco-friendly option, great for homes with surrounding vegetation.
- Commercial products – look for labels like “Roof Cleaner” or “Moss & Algae Remover” at Canadian hardware stores.
Step-by-Step Roof Cleaning
Step 1. Inspect the roof
Check for damaged or missing shingles. If you notice serious issues, call a roofer first.
Step 2. Prepare the area
Cover plants, shrubs, and lawn areas with plastic sheeting to protect them from runoff.
Step 3. Apply the solution
Use a garden sprayer to apply the cleaner evenly, starting from the bottom of the roof and working upward.
Step 4. Let it sit
Allow the solution to soak for 15–20 minutes (or follow product directions). This loosens moss, algae, and mold.
Step 5. Scrub gently
With a soft brush, carefully remove moss, working from the top down to avoid lifting shingles.
Step 6. Rinse
Wash the roof with a garden hose on regular pressure. Avoid high-pressure water that could strip shingle granules.
What Not to Do
- Don’t use a pressure washer – water jets can strip the protective surface and cause leaks.
- Don’t use metal brushes – they scratch and damage shingles.
- Don’t work alone – it’s safer to have someone nearby.
- Don’t ignore the weather – choose a cool, dry day for cleaning.
Preventing Moss and Mold Regrowth
- Install zinc or copper strips along the ridge: rainwater carries ions down the roof, discouraging growth.
- Trim overhanging trees to reduce shade and excess moisture.
- Keep gutters clear so water flows freely and doesn’t pool.
- Reapply preventative treatments every 2–3 years.
Roof Care Across Canada
Canada’s climate creates different roofing challenges:
- British Columbia and coastal regions: High humidity encourages rapid moss growth.
- Alberta and the Prairies: Dust and dirt carried by winds are the main issue.
- Ontario and Quebec: Spring often brings black streaks from algae buildup.
Because of these variations, cleaning methods and frequency may differ by region.
When to Call the Pros
If your roof is heavily soiled, very steep, or damaged, hire professionals. Roofing companies often use soft washing, a low-pressure method that cleans effectively without harming shingles.
Professionals can also spot early signs of problems that homeowners might miss.
Sometimes homeowners think their roof just looks bad from stains or moss and hope cleaning will restore it. But if shingles are cracked, worn down, or missing granules, cleaning won’t solve the problem. In those cases, repairs or even a full Calgary roof replacement may be necessary. Cleaning alone may temporarily improve the look, but it won’t stop deterioration.
Final Thoughts
Cleaning asphalt shingles is an essential part of home maintenance in Canada’s climate. Preventative care helps extend your roof’s life, improves curb appeal, and saves money on future repairs.
The key is to work carefully, use the right tools and solutions, and know when it’s best to leave the job to professionals.
If you want to know whether your roof needs a simple cleaning, repairs, or a complete replacement, it’s best to start with a roofing estimate Calgary.
