When it comes to EPDM Roofing (Ethylene Propylene Diene Monomer) it's important not to rely solely on the membrane itself. What goes underneath is equally important!
The Essential Layers Under an EPDM Roof
Roof Decking
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Material: The base layer of an EPDM roof is the roof decking. Common materials for decking include plywood, OSB (Oriented Strand Board), or metal.
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Purpose: This layer provides a stable, smooth surface for the EPDM membrane to adhere to. It’s crucial that the decking is clean, dry, and free from any sharp objects or debris that could puncture the membrane.
Insulation
- Types: Polyisocyanurate (Polyiso), expanded polystyrene (EPS), and extruded polystyrene (XPS) are commonly used insulation materials.
- Purpose: Insulation improves the energy efficiency of the building by reducing heat loss in the winter and heat gain in the summer. It also provides a flat surface for the EPDM membrane, enhancing its performance.
Vapour Barrier
- Material: Typically, a vapour barrier is made of polyethylene or similar materials. Alutrix 600 is a very popular choice - which we supply lots of!
- Purpose: This layer prevents moisture from penetrating into the insulation and the building structure, which can cause mold, mildew, and structural damage.
Cover Board
- Material: High-density fiberboard, gypsum board, or a similar product is often used as a cover board.
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Purpose: The cover board provides additional protection for the insulation layer and creates a smoother surface for the EPDM membrane. It also helps to distribute the load evenly across the roof.
Installation Tips for an EPDM Roof
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Preparation: Ensure the decking is properly installed and in good condition. Any imperfections should be repaired before proceeding with the insulation and vapor barrier layers.
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Layering: Carefully install each layer, starting with the vapor barrier, followed by the insulation, and finally the cover board. Each layer should be secured according to manufacturer recommendations to prevent movement and ensure a stable base for the EPDM membrane.
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Adhesion: The EPDM membrane is typically adhered to the cover board using a special adhesive. It’s important to follow the adhesive manufacturer’s instructions for the best results. Make sure the membrane is laid flat and free from wrinkles or air pockets.
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Seams and Edges: Properly sealing the seams and edges of the EPDM membrane is crucial to prevent leaks. Use seam tape or adhesive as recommended, and ensure all edges are securely fastened.
Closing Thoughts
A well-installed EPDM roof requires careful attention to the layers beneath the membrane.
By ensuring you have a solid roof decking, effective insulation, a reliable vapour barrier, and a durable cover board, you can maximise the performance and longevity of your EPDM roof.
These layers work together to provide a stable, energy-efficient, and weather-resistant roofing solution that can withstand the elements for many years.
Investing time and resources into the correct installation process will pay off in the long run, providing you with a roof that not only performs well but also adds value to your property.
Whether you’re a professional roofer or a DIY enthusiast, understanding the importance of what goes under an EPDM roof is essential for achieving the best results. Contact us if you have any further questions.