When it comes to re-covering a slate roof, building codes and best practices play an important role in ensuring the long-term durability and safety of the roof. Generally, slate is a premium roofing material known for its longevity and natural beauty, but it is also heavy and brittle, which means the underlying structure must be able to support any additional weight if new slate or underlayment is added on top of the existing roof. Codes typically require removing the old slate down to the roof deck before installing a new slate roof to avoid excess weight and to inspect for any hidden damage like rot or warped sheathing. Some areas might allow a partial re-cover with specific types of underlayment and fastening methods, but this is usually the exception rather than the rule. Homeowners or roofers should check local building codes and manufacturer warranty terms because improper layering or fastener use can void warranties and lead to premature failure.
To make a simple DIY check, safely inspect the roof from the ground or a stable ladder for signs of broken, curling, or missing slates, as these indicate it’s time to consider repairs or replacement rather than another layer. Also, look for any leaking or water damage inside the attic, which often points to failed roofs needing full attention. If you’re unsure about the condition or code compliance of a slate re-cover, it’s best to call a licensed roofing contractor with slate experience. When hiring a contractor, ask if they will remove the existing slate completely and if their work complies with your local building codes and slate manufacturer’s warranty requirements. Also, clarify how they will address the roof deck condition to ensure a solid base before re-covering. This approach helps avoid costly mistakes and extends the life of your slate roof.