What Causes Water Streaks on Interior Walls?

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Water streaks are unsightly and may indicate further damage behind the wall.
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Excess moisture inside your home can cause water streaks on interior walls and ceilings. This moisture can come from a number of places. Once you know the specific reason for the water streaks on your walls, you can repair the problem and clean the unsightly stains away. Keep in mind that water streaks are more than simply an eyesore. They could indicate rot and mold growth behind the wall, a fact that puts a sense of urgency on repairing the issue as soon as possible.


Roof Leaks and Ice Dams

Roofs serve an important role in protecting your home from rain and other sources of moisture. If your roof gets damaged, water finds its way in and can cause water streaks and other damage. Roof damage can happen from storms, improper installation and impact. Your roof can also deteriorate over time and allow leaks.


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In cold climates, ice dams can cause roof damage and leaks in the winter. The water behind these frozen dams builds up and often finds its way beneath the shingles. The most likely place for this to occur is directly above the exterior walls because warm air escapes here and melts the ice. When this happens, water streaks appear near the top of walls in rooms located on the highest story of your home.


Clogged or Damaged Gutters

Your gutters are also important in keeping water away from your home. Leaves, twigs and other debris collect unless you clean your gutters regularly. This can cause water to back up in the gutters and spill over the sides.

Poor drainage allows water to seep under the shingles or create water problems at your home's foundation. If water from your roof is directed toward the foundation instead of away from it, you may notice water streaks on interior walls near the floor of the first story or coming down from the ceiling in the basement.


Excessive Indoor Humidity

Sometimes water streaks on interior walls aren't caused by moisture on the outside at all. There are several indoor sources of moisture that lead to water stains, including your everyday activities, such as cooking, showering, washing clothes and even breathing.


Continuous overuse of humidifiers, clothes dryers that vent into the living space, crawlspaces without vapor barriers and plumbing leaks are all issues you can remedy to solve the problem of high indoor humidity levels. Installing and using exhaust fans in bathrooms and kitchens where humidity-generating activities happen can also help.

Inadequate Home Ventilation

Your home's ventilation offers many benefits. Not only does it remove excess moisture to prevent water streaks, but it also helps remove pollutants and control heat. Without proper ventilation, the excess moisture can result in streaks on your walls.


If your home has a moisture problem resulting in water streaks on interior walls, the best way to fix the problem is to increase ventilation. Spot ventilation is the use of exhaust fans in particularly humid areas of the home, such as the kitchen and bathroom. If spot ventilation isn't enough to get rid of excess moisture, a whole-house ventilation system should be considered. Whatever kind of ventilation you select, ensure that exhaust fans are vented to the exterior, not the attic or another interior location.



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