The first step in determining the location of the problem area is to discuss the issue with the owner, building manager or maintenance staff and review the problem area.

During discussions with building staff, ask questions such as the following:

• How much moisture is involved?
• For what length of time has the roof been leaking?
• What at the weather conditions when the leak occurs?
• Is the wind blowing when the problem occurs? If so, from which direction?
• Does the problem occur when the wind is not blowing or is blowing from a different direction?
• Does the leak occur at the start of the rainfall or was there a slight delay?
• Does the leak continue after the rain stops?
• Are there plumbing, drainage, mechanical systems or other sources of water that may be contributing to the problem?

The answers to the above will assist you in determining the potential locations of water ingress. The location and cause of water leaks does not always occur directly from above. Although this location should be the first place on the roof surface that is checked, water may also be travelling within the roof assembly. The entire roof area and adjacent walls and rooftop equipment should be reviewed.

While inside the building, use the exterior doors, windows, roof drains, plumbing and mechanical vents, etc., to assist you in identifying the location of the problem. When on the roof surface, use these objects to help you locate the problem area.

The visual inspection of the roof surface should include the following:

• Mark the leak location and visually inspect the immediate area.
• Check for cracks, blisters, soft spots or fasteners that have popped up. If you step on an area, water or air usually escapes to the surface from an actual hole.
• Some of the most common types of roof leak occurs at roof penetrations such as roof anchors, exhaust vents, drains etc. All roof penetrations must be examined closely.
• To examine the roofing membrane, it may be necessary to use a broom to remove loose gravel or debris from the area.
• With a protected membrane system, it may be necessary to remove gravel and insulation in order to expose the membrane to examine the problem area.
• If you cannot locate the problem in the immediate area, then you must examine the roof surface in a systematic manner, out from the starting point.
• Note the direction of the slope of the roof deck as moisture may be travelling within the roof system from a point further up the slope. Steel and concrete decks will definitely cause moisture to travel. On steel decks, note the direction of the flutes. These channels act as gutters, allowing water to travel a long distance before finding an opening.
• Be sure to examine parapets and sidewalls for cracks or deterioration. Curbs, with missing flashing, may also cause problems.

There are several other tools such as thermographic inspection and electronic leak detection that may assist in locating the problems. These tools should be used by personnel that have been trained in the use of the particular equipment.