While water dripping inside the building is a clear indication that you have a roof leak, other signs of a leak in a commercial roof are less obvious. Knowing what to look for and the potential causes of a leak can help you determine the next steps to getting your roof repaired and the damage fixed.
If you see any of these signs, don’t wait for the damage to get worse before calling a roofing professional. Putting off repairs only leads to more extensive and expensive damage, ultimately costing you more in the long run.
Exterior signs of a roof leak
Look for these signs of a commercial roof leak by inspecting your roof after a rainstorm:
- Bubbles or blisters in the roof membrane, indicating moisture may be trapped underneath
- Roof surface cracks, tears, or punctures
- Open seams between membrane roofing sections
- Damaged or cracked flashings (the metal or rubber flashing found around pipes, vents, or equipment curbs)
- Sagging roof structure or standing/ponding water
- Clogged roof drains, gutters, or downspouts
- Loose, cracked, or missing roofing materials (especially along the roof edge)
- Signs of corrosion or rust on a metal roof system or other metal components
- Seedlings sprouting on the roof are signs that water has infiltrated the roofing system
Interior signs of a roof leak
These signs, found in the interior of a building, may indicate that you have a roof leak:
- Discoloration on ceilings or walls, often colored brown or yellow
- Dripping water from the ceiling or running down walls
- Puddles of water on the floor
- Musty or damp odors, which can indicate the presence of hidden moisture
- Mold or mildew growth on ceilings or walls (look for black stains)
- Bubbling or peeling paint or wallpaper
- Warped or sagging ceiling tiles
- Warped or damaged structural beams
- Increasing energy costs, as water can damage insulation and lead to a higher need for heating or air conditioning
Water travels the road of least resistance, so if you see a leak on the inside of the building, that doesn’t necessarily indicate where the leak is located. A professional can help trace the water’s path and determine the underlying cause.
Common causes of commercial roof leaks
There are several potential causes of roof leaks in commercial buildings. Narrowing it down to the correct one takes expertise and years of experience. Professionals have specialized tools, such as infrared cameras, to help them identify hidden water damage and pinpoint the source of a leak. Calling a professional at the first sign of a leak will save you trouble and costs in the long run.
Here are some common causes of commercial roof leaks:
- Clogged or poorly designed roof drainage system
- Damaged membrane or other roofing material
- Damaged flashings or unsealed penetrations
- Roofing material age, wear and tear
- Poor roof installation or repair
- Build-up of debris
- Storm damage caused by falling or wind-blown debris
- Lack of maintenance
For more information, check out our articles, “How to Prepare Your Commercial Roof for Winter,” “Checking Your Commercial Roof for Damage,” and “Tips for Post-Storm Roof Damage Assessment.”