A green roof is a layer of vegetation planted over a waterproof membrane on a roof, offering benefits like insulation and stormwater management. Ponding water on a green roof happens when water accumulates and remains standing in low spots instead of draining away. This often occurs because of poor roof slope, clogged drainage systems, compacted growing media, or design flaws where insufficient drainage layers or outlets are installed. Prolonged ponding can damage the roof’s waterproof membrane, increase the weight load, harm plants, and reduce the overall lifespan of your green roof system. It’s important to catch ponding early since constant standing water adds stress and can void some warranty conditions if left unaddressed.
Homeowners can do simple checks like observing if water pools after rainfall, making sure gutters and drains are clear of debris, and looking under plants for soaked or dead areas where water is trapped too long. Avoid walking on wet or soft spots to prevent damage. If ponding is present or worsening, it’s time to call a roofer familiar with green roofs. When consulting a contractor, ask, “How will you improve drainage while protecting the waterproof layer?” and “Do you recommend maintenance steps or fixes that won’t void my manufacturer’s warranty?” These questions help ensure the roofer plans solutions that are both effective and safe, maintaining the performance and longevity of your green roof.