3 Unsuspected Causes of your "Roof" Leak

April 02, 2014

Do you have a leak that just won't go away? Have you tried everything - patching, coating, and calling numerous roofing contractors, but the inevitable drip still remains? Well, it may be that the problem isn’t the actual condition of the roof. It may stem from a variation of other behind-the-scene problems. If left unattended, these issues may lead to an unexpected and costly roof replacement!

If you want to put your mind at ease, while keeping money in your pocket, then you’ve come to the right place. This blog post will not only highlight the top 3 unexpected causes of your “roof” leak, but will give you the tips and tricks to plug those pesky problems at the first signs of trouble!

The top three warning signs to look out for include condensation, rooftop units, and adjacent structures.

If accessible, the first step you should take to find the cause of your leak is to look in the ceiling to see where the water is coming from. The most common misconception while tracing a leak is, "if water is dripping here, there must be a hole right above it". Once in the ceiling you may be able to rule out our first unsuspected cause of your leak, condensation. Condensation forms because warm air is coming in contact with cool air. For instance, when you have your favorite cold beverage and water or "sweat" forms on the outside of the glass because of the severe difference in temperatures. However, swapping out your glass for an insulated mug prevents condensation from forming. The same thing goes for your attic or ceiling space. Water droplets will form on the underside of the roof deck, if you do not have enough insulation in your roof system. The drastic change in temperature from warm inside and cold outside can cause condensation to appear on the deck of your roof. On the flip side, if it is hot outside the same thing can occur inside if the air-conditioning duct is not properly insulated, resulting in the leaking of cool air into the space. This leads us to our next unsuspected cause, roof top units.

While tracing the leak from your ceiling, you may see duct work attached to a roof top unit, also known as an RTU. RTUs have been plaguing roofers for years. In most cases an RTU is a heating, ventilation, and air conditioning unit. Typically, these units are not built to be water tight, but are built to have the water run out of them and onto the roof through a drain or holes in the casing. However, if the drain or hole is blocked water will collect in the unit giving it only one other place to go, into your duct work. If nothing is blocking the drain, make sure all compartments are properly shut without any missing screws or bolts. If you are confident the unit is not causing an issue, there may be masonry wall or other buildings connected to the area serving as the main culprit.

Just because the leak is in the middle of the room, does not mean the water isn't traveling along the structure before dripping onto your ceiling. Moisture can leach into the masonry, flow down the inside of the wall until it finds a cross beam or other support structure, run down the support structure, and eventually drip onto your ceiling. While exposed to the elements, masonry walls can slowly wear away or may even crack from expansion or settling. When inspecting the wall, be sure to look for any cracks in the masonry and crumbling of the mortar. Plus, you’ll want to ensure there is a proper thru-wall flashing (if present) and is sealed. While at the wall it never hurts to see what is on the other side; you may be surprised at what you find. There is no need to inspect your neighbors’ roof but just take a quick glance to make sure it is still there.

Inspecting your ceiling space, roof top units, and adjacent structures, will help you find the cause of your "roof" leak. This will give you a better understanding the next time you call your roofing contractor to fix your issue. If, you have already eliminated these locations and have not had any luck finding the cause of your leak, it may be time to call in a professional. Most reputable commercial contractors will give you a free roof inspection. With a thorough inspection they should be able to find the cause of your problem.

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