The causes of leaks in flat roofs can be difficult to find, and some business owners have invested thousands of dollars in repairs trying to end frustrating leaks. However, the reality is that some leaks are not a direct result of roof damage but are instead caused by other problems. Below are four non-roof related sources of moisture intrusion that may appear to be caused by leaky roofs, but are not:

Wall exterior absorption of moisture

One such source of water intrusion through ceilings is wall surface absorption; brick and stucco exteriors are both susceptible to this particular problem. In this situation, the wall of a structure that is erected above the flat roof, such as a second floor, serves as a wick for rainwater or melting ice and snow. Brick, including the mortar joints, and stucco are both fairly absorbent materials, and water passes through them to the other side of the wall. If there is no accommodation for the water to be diverted through weep holes, then it will ultimately pool in interior spaces and soak through ceilings.That is why building owners should seal their brick and stucco exteriors to prevent water from passing through into interior spaces. Sealants can be applied by professionals or as a do-it-yourself project by dedicated property owners and managers.

Air conditioner evaporator drainage

Another source of water intrusion that mimics a roof leak is air conditioning unit condensate accumulation. If your air condition system contains evaporators mounted above the ceiling of your building, then these should be suspected if a leak appears. Evaporators can remove literally gallons of water from the air during humid conditions, and the condensate must be drained effectively to prevent an overflow. Unfortunately, drain pipes can fill up with slime bacteria and mold and become impassable as a result. The condensate then ends up inside ceiling spaces and drips into the building.

You will notice apparent leaks during the warmest parts of the year and few, if any, during the winter months if the air conditioner is not disposing condensate properly. In addition, you should also consider inspecting your air conditioner drain lines to ensure they are not clogged; a cup of laundry bleach can quickly clear up organic growth inside the drain. Also, be sure that your air conditioner has an appropriate drain pan installed beneath the inside equipment. This pan should be capable of holding several gallons of water before overflowing and will help prevent damage.

Leaking water or sewage plumbing

A possible source of moisture inside a flat-roofed building is due to leaks in the plumbing. It is not uncommon for water supply lines and sewage lines to develop leaks which drain into the ceiling. These leaks are characterized by the fairly consistent presence of moisture, even when the weather is dry, and in the case of sewage plumbing leaks, there will be a foul odor present. All plumbing leaks pose an immediate hazard, especially in the case of raw sewage, and leaks in the fire suppression system that supplies sprinkler heads can be deadly if the system fails as a result. Unfortunately, repair will require the assistance of a professional plumber and may involve clean-up if sewage is involved.

Hydrostatic pressure

In buildings that are partially beneath the ground, either on a slope or those that contain a full basement, be sure to rule out hydrostatic pressure as a possible cause of water intrusion. Hydrostatic pressure is literally the "force" of water in the surrounding soils, and it can push its way into minute spaces in the side of a wall. Hydrostatic pressure-related leaks are tricky; they will frequently appear after rain, just the same as a roof leak. That is why inspection of the interior of the wall will be necessary, and may even involve the necessity of digging into the soil surrounding a wall's exterior. Solutions for hydrostatic pressure-caused leaks include adding french drains, sealing joints and soil removal to lessen intrusion potential.

For more information, contact a commercial roofing contractor.

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