11/03/2026
Standing water on a flat roof isn't always a problem, but how long it stays there matters. 💧🏢
Flat roofs are designed with drainage in mind, but low spots, clogged drains, or inadequate slope can sometimes cause water to collect.
So when should you be concerned?
A commonly used guideline in commercial roofing is 48 hours. If water is still sitting on your roof more than 48 hours after rainfall has stopped, under normal drying conditions, it's worth investigating.
Persistent ponding water can contribute to:
💧 Premature deterioration of certain roofing materials
🔧 Additional stress on seams and vulnerable areas
🏢 Increased risk of leaks if the roofing membrane is compromised
Not every puddle indicates a serious issue, and different roofing systems handle standing water differently. But if the same areas consistently hold water for days, having the roof and drainage system evaluated is a smart move.
Have questions about your commercial flat roof? TLC Roofing can help!