Aluminum underlayment is a type of roofing material that acts as a protective barrier between your roof deck and the outer roofing materials. It is typically made from a thin layer of aluminum foil laminated to a waterproof substrate, designed to reflect heat and provide added moisture resistance. This underlayment is often used in areas with high sun exposure because it helps reduce roof temperatures, potentially extending the life of the shingles or other roofing materials above. However, aluminum underlayment can be less flexible than synthetic or felt underlayments, which sometimes makes installation a bit trickier, especially on roofs with complex shapes or steep slopes. Over time, it can also be prone to tears or punctures, so proper installation and maintenance are key to ensure lasting protection.
To check if your underlayment is aluminum or another type, safely access your attic or an edge of the roof where the underlayment may be visible. Aluminum tends to be shiny and metallic, whereas felt and synthetic types are more matte and fibrous. If you're noticing heat issues inside your home or suspect roof leaks, inspecting the underlayment is a good step, but avoid walking on your roof if unsure about safety. If you decide to call a roofer, ask specifically if they recommend aluminum underlayment for your climate and roofing materials. Also, confirm how using aluminum might affect your roof’s warranty, as some manufacturers have strict requirements about underlayment type. Questions like “Does aluminum underlayment improve energy efficiency for my roof?” or “How does it impact my roofing system’s warranty and long-term maintenance?” will help guide your decision.