One slate roof can last over 100 years, but only if properly maintained. Many homeowners believe that a slate roof requires no care, leading to costly, avoidable repairs in the long run.
This guide explains how to protect your investment with simple actions. You'll know what to watch for, when to take action, and how to avoid common mistakes. No technical knowledge is required.
What to remember
- Slate is durable, but fasteners and solining may deteriorate
- Inspect twice a year : in spring and autumn, look for anomalies and signs of wear
- Act quickly if you notice displaced slates or water ingress
- Call on a specialized roofer : walking on slate can break it
Why is the maintenance of a slate roof essential?
Natural slate is weather resistant, but it's not the only part of your roof. Copper or zinc nails, hooks, and knots can rust or loosen over time.
Freeze and thaw cycles in Montreal accelerate wear and tear. A cracked slate allows water to penetrate, which damages the wood structure underneath. Regular maintenance prevents these problems before they become serious. A water repellent treatment is recommended.
Signs to look out for when inspecting the roof
Perform a visual check from the ground with binoculars. Never climb onto a slate roof without proper equipment.
Items to check:
- Displaced, cracked, or missing slates
- Appearance of moss or accumulation of debris between the slates
- Damaged solination around chimneys, dormers and valleys
- Clogged gutters by fragments of slate blocking rainwater
- Traces of water infiltration in the attic or on the interior ceilings
If you notice any of these signs, contact a roofing specialist in slate roofing.
What to do and when to call in a professional
The recommended maintenance guide
1. Bi-annual inspection
Examine your roof in the spring after the snow melts and in the fall before winter. Note any visible changes.
2. Gutter cleaning
Remove leaves, branches, and debris that block water drainage. Gutters obstructions cause backflows that damage the slates and the structure.
3. Removing moss and debris
If foam builds up, seek professional help for gentle cleaning. Never use pressure washers: the force of water can break the slate and damage the fasteners.
4. Solination check
Metal solination (copper, zinc) must be waterproof. Cracks or uplift should be repaired immediately to prevent water ingress.
5. Replacing damaged slates
A broken slate should be replaced by a qualified roofer. The replacement slate must match in type, thickness, and color to maintain the integrity of the roof.
To find out more about installation standards in Quebec, consult the Régie du Bâtiment du Québec.
Common mistakes to avoid
Walk directly on the slate
Natural slate is fragile under weight. Only a roofer with suitable roof ladders should access it.
Use a pressure washer
Excessive pressure loosens slates and damages joints. Choose gentle manual cleaning or a soft brush.
Ignoring small problems
A displaced slate seems minor, but it allows water to seep in. Repairs cost less when done early.
Apply aggressive chemical treatments
Some anti-foam products corrode metal and slate. Use only products that are designed for natural stone roofs.
Best practices for extending shelf life
- Prune tree branches that overhang the roof to reduce the accumulation of debris and shade (which favors moss)
- Maintain a good ventilation in the attic to avoid condensation
- Document your inspections with dated photos to follow the evolution of the roof
- Choose an RBQ certified roofer having experience with natural slate
The Scientific and Technical Construction Center offers resources on maintaining roofing materials.
Protect your investment
One slate roof Well maintained protects your home for decades By inspecting regularly, cleaning gutters, and fixing small problems quickly, you avoid major costly interventions.
Slate is a noble material that deserves proper maintenance. With the right actions and the help of qualified professionals, your roof will maintain its beauty and performance.
Contact us for a professional interview
If you notice signs of wear or if your last inspection was more than a year ago, our team can assess the condition of your roof and offer you a maintenance guide customized.
Contact us, we'll help you understand priorities and plan interventions at the right time.
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