A green roof, often called a living roof, involves growing vegetation over a waterproof membrane on top of your building. The underlayment beneath this membrane plays a crucial role in protecting your roof’s structure from moisture, roots, and physical damage while ensuring proper drainage. Typically, the underlayment for a green roof includes a root barrier and a drainage layer that prevents water from pooling and causing rot or leaks. The exact requirements depend on the type of green roof you have—extensive (lighter, with shallow soil) or intensive (heavier, with deeper planting beds). Underlayment materials must be durable, puncture-resistant, and compatible with both the waterproof membrane and the soil used, as improper installation can lead to leaks or root intrusion. For a safe DIY check, inspect your roof’s waterproof membrane for visible damage or signs of moisture below it, especially after heavy rain, but avoid disturbing the plants or soil yourself. If you notice water pooling, leaks inside your home, or any structural sagging, it’s a good sign to consult a professional.
When calling a roofer experienced in green roofs, it’s important to ask specific questions to ensure they understand the unique needs of your setup. You might want to ask, “What type of underlayment and root barrier do you recommend for this specific green roof system, and why?” This helps confirm they know about materials that prevent root damage and provide adequate drainage. Another useful question is, “How do you handle warranty coverage when installing or inspecting green roof underlayments?” Since green roofs have different warranty considerations than traditional roofs, understanding coverage will protect you against future repair costs. Choosing a roofer with knowledge of local codes and water management requirements will ensure your green roof remains both beautiful and functional for years to come.