To a large extent, successful roof applications are completed by skilled mechanics that conduct systematic tasks in a repetitive manner. Repetition increases the skill level, which in turn increases productivity. This is a constant in an industry that (largely) derives profit from production. Most companies train their mechanics to be productive workers. There is one sector of the industry that requires a different mindset: the repair sector. Skills required here include patience, persistence and analytical thought.
Service divisions run contrary to the rest of the company. Profit margins (which are typically higher than production work) are not generated by production rates but rather by results. Stop the leaks and you get paid. If you don't stop the leaks, you are likely to have trouble collecting from the owner. The key to fixing a leak is properly identifying the source of the leak. This can be a difficult task.
If finding the source of a leak is accomplished through a systematic and efficient approach, the rate of effective repairs will increase. Some leaks, such as holes in a membrane, are straightforward, and the source can be identified almost immediately. Finding the source of other leaks requires diligence. The leak respondent should be an individual who is prepared to use any means necessary to properly detect the leak.
Most leaks occur at penetrations, such as pitch pans.
Detective Work
Leak detection can begin at the notification stage through collection of important information. In addition to finding out the deck and roof system type, the leak responder should try to find out what, where, when and how the leak is occurring. This valuable information could limit the inspection time by focusing on specific trouble spots. The type of roof system may indicate possible problem areas based on inherent concerns related to specific material systems. Historical knowledge of the existing roof system - when available - could also provide insight into the issues related to the roof leak.The initial step in leak detection is too determine where the leaks are reported and to know exactly where to start looking for them on the roof system. This can be achieved through measurement of the roof leak off of an identifiable interior marker, such as an exterior wall, a mechanical unit or an interior drain. A best practice is to plot the interior roof leak location on a drawing for easy identification on the roof. It is also a good idea to plot any old roof leaks identified in an area (often indicated by old water stains on ceiling tiles or walls) to determine if the new leak is associated with old repairs.
During the course of the interior inspection, the leak respondent should determine the type of roof deck installed in the leak area. Deck types can affect how far the water from the leak travels to the interior of the building. Water often enters the facility from openings in the deck, which may not be the point at which they entered the roof assembly. The direction of the steel deck or concrete panels can assist in locating the potential entry point on the roof and determine how far the water travels from the leak source to the interior of the building.
The leak respondent should also inspect all plumbing lines, drain lines or pipe lines to determine if the leak is associated with a loose fitting or condensation on cold pipes. HVAC units are also common points of suspected roof leaks. Leaks from HVAC units originate from condensation, overflow of condensate pans, or openings in the unit housing. Leaks that occur on dry days can often be attributed to these types of conditions.
Once the leak location is identified, it is important to determine how long the leak has been occurring. The manufacturers require that owners notify them of roof leaks within 24 hours of occurrence; however, there are times when roof leaks are undetected or not reported for longer periods of time. If the leak has been occurring in the area for a significant amount of time, it may contribute to potentially dangerous situations like structural deterioration or mold formation. If it is a current leak, determine whether penetrations have been made recently to install new pipes, units, etc., in the area. Improper penetration preparation may be the cause for the leak.
It is important to determine when it leaks. For instance, does it leak after all rains or is it only under specific conditions? Leaks that occur after wind-driven rains may be from irregularities in flashings or other building component openings, such as windows or walls. Wall leaks account for a number of suspected roof leaks, particularly from openings at coping joints or edge metal terminations. Identification of exterior wall leaks can be from movement cracks or other structural deformations. It is also recommended that the leak respondent inspect around windows, doors or building joints that rely on sealant for waterproofing protection. Sealants delaminate with time, creating openings for moisture entry.
Up on the Roof
Once on the roof, leak detection should focus on the areas centered around the interior leak plot locations and be conducted through a process of elimination. The most obvious source of leaks is at penetrations and flashings. These areas account for two-thirds of all roof leaks. Equipment curbs, pipes, pitch pans, and other penetrations in the area should be thoroughly inspected for deficiencies. If penetrations and flashings are intact, then a thorough inspection of the membrane is required. Membrane deformations such as punctures, splits, open seams and blisters, if discovered, should be repaired. The leak responder should also identify any areas of membrane discoloration or fungi growth as potential leak areas. A leaf blower should be used to remove ponded water or water over aggregate from the area for proper inspection of the membrane. The membrane inspection should begin in the plot area and continue up-slope in all directions. Any leaks that are entering the system at another point will likely occur up-slope, since water only has the ability to flow downhill.Roof leaks that are not detected through visual inspection may require further analysis using test methods and investigative equipment. The first investigative method that should be considered is water testing. Water tests can be conducted in three forms, with the initial method completed through the introduction of sprayed water in the area. Oftentimes, roof openings may be minimal or covered with aggregate or other roof contaminants, and the human eye may not detect them. Some membrane materials - under certain conditions - are prone to water wicking, which would be extremely difficult to detect visually. Spraying water in the area to simulate a rainfall may identify these conditions.
If the roof leak does materialize from the spray process, flood testing may be required. Through this process the roof section in question is blocked off (using sandbags or other impediments) and all drains in the area are plugged. The water level should be maintained at 1 to 3 inches for 24 hours (or until the leak is evident). Bubbles in the water typically define leaks. A colored dye can be introduced in the water testing process if the location of the leak is not determined. In these cases, advise the building owner of the probability of colored stains at interior surfaces.
Investigative equipment used in leak detection could range from hand-held meters to advanced equipment such as infrared or nuclear scan equipment. Hand-held capacitance meters are ideal for identifying probable wet points in the system. These types of meters are easy to use and inexpensive. Wet areas identified by the meter could indicate moisture entry from the existing leak and provide a specific area of investigation. It is always recommended that wet materials be removed and replaced even in repair conditions.
Advanced technology such as infrared and nuclear scans should only be considered in extreme cases. These types of investigations are costly and must be completed by trained and certified individuals - typically a third-party inspection agency. If there are a number of leaks, this process may be advantageous.
