Preventing Leaf and Moisture Damage on Cedar Shake Roofs
Cedar shake roofs are one of the most beautiful, high-end roofing choices available in Toronto — but their natural charm comes with a unique set of care requirements. While cedar is naturally resistant to rot and pests, our city’s leaf-heavy autumns can still create moisture problems if homeowners aren’t proactive. At Top Roofers, we install and maintain cedar shake roofs across the GTA, and we’ve seen how quickly neglect in the fall can shorten a cedar roof’s lifespan. In this guide, We’ll explain why leaves and moisture are a concern, and exactly how to protect your investment.
Why Leaves Are the Enemy of Cedar Shake Roofs
When leaves collect on a cedar roof, they don’t just look messy — they create a blanket that traps moisture against the wood. This can lead to:
Moss and Algae Growth – Damp, shaded conditions are perfect for moss and algae, which can lift shakes and allow water penetration.
Accelerated Decay – Even cedar’s natural oils can’t fully protect against constant moisture exposure.
Weight and Drainage Issues – Piles of wet leaves are heavy and can block water flow into gutters, causing water to back up under the shakes.
Freeze-Thaw Damage – In late fall, trapped water can freeze overnight, expanding and splitting the shakes.
Toronto’s Moisture Challenge
Cedar roofs in drier climates have it easy compared to ours. In Toronto, fall often means:
Weeks of wet weather
Heavy leaf fall from mature maples and oaks
Repeated temperature swings above and below freezing
These conditions are why even the highest-quality cedar needs seasonal care here.
Step-by-Step Cedar Shake Roof Protection
1. Schedule a Professional Roof Cleaning
Late September or early October is the ideal time to clear debris from your roof because it allows you to prepare your home before the heaviest leaf fall begins. Removing leaves, twigs, and other debris at this stage ensures that your roof starts the season clean, reducing the risk of clogged gutters, water damage, and roof deterioration. By addressing these issues early, you help maintain the integrity of your roofing system and avoid costly repairs later in the fall and winter months. This proactive approach supports optimal roof performance and extends its lifespan.
2. Keep Gutters Clear
Blocked gutters cause water to pool on your roof edge, soaking the lower shakes. We recommend cleaning gutters at least twice each fall — once mid-season and once after most leaves have dropped. This prevents water damage, reduces the risk of leaks, and extends the lifespan of your roof. Regular gutter maintenance helps ensure proper water drainage, protecting your home’s foundation and landscaping as well. At Top Roofers, our team can assist with thorough gutter cleaning to keep your roofing system in optimal condition.
3. Prune Overhanging Branches
Reducing leaf drop and improving airflow are essential steps in helping your cedar dry out more quickly after rainfall, thereby preventing moisture buildup that can lead to rot and mold. At Top Roofers, we recognize the importance of a healthy, well-ventilated environment around your cedar shingles to maintain the integrity of your roof and surrounding structures. To achieve this, we often collaborate with professional arborists who carefully trim back branches in a safe and controlled manner. This teamwork ensures that the trees are healthy and pose no risk to your roof while optimizing airflow and minimizing leaf accumulation. By combining our roofing expertise with arboricultural knowledge, we provide comprehensive solutions that protect both your home and your trees.
4. Apply a Protective Treatment
Cedar shakes benefit from periodic treatments that:
Restore natural oils
Add UV protection
Reduce water absorption
Tip from Bruno: This is best done on a dry day in early fall, before the season’s heaviest rains.
5. Address Moss or Algae Early
If you spot moss growth on your roof, don’t ignore it. Moss retains moisture, which can seep into the wood beneath your shingles or shakes. Over time, this moisture can cause the wood to rot and weaken, leading to structural damage. Additionally, moss roots can lift and dislodge shakes, compromising the roof’s integrity and making it more vulnerable to leaks and further damage. Prompt removal and proper maintenance are essential to preserving the lifespan and quality of your roof.
6. Inspect Flashing and Valleys
Leaves often accumulate in roof valleys, which are essential channels for directing water off your roof. These valleys must remain clear to prevent water buildup that can lead to leaks or structural damage. Flashing plays a crucial role in waterproofing by directing water away from joints and seams. Over time, metal flashing can show signs of corrosion, rust, or develop gaps that allow water to seep beneath the shingles or shakes. Detecting and repairing these issues early helps preserve the roof’s integrity and prevents costly water damage to your home. Our thorough inspection and maintenance services ensure that your roof remains watertight and durable throughout Toronto’s varying weather conditions.
Why You Shouldn’t DIY Certain Cedar Maintenance
While clearing a few leaves with a leaf blower is fine for homeowners, cedar maintenance is delicate work. we’ve seen well-meaning DIY jobs that left shakes cracked or even pulled loose. With a premium roof, the cost of fixing accidental damage often outweighs the savings of doing it yourself.
The Cost of Neglect
Ignoring leaf and moisture issues on a cedar roof can lead to:
Premature shake replacement
Structural rot in the roof deck
Mold growth in the attic
For a material that can last 30 to 50 years with proper care, that’s a preventable waste.
Cedar shake roofs are a premium investment — but in Toronto’s climate, they need seasonal attention to perform their best. By staying ahead of leaf and moisture damage this fall, you’ll not only protect your roof but also preserve the natural beauty that makes cedar so special.