Why Brown Streaks on Siding Is a Sign of Water Damage & What to Do About It

If your house has brown streaks on the siding, you may have significant water damage in your attic and roofing. Even though the problem causing the brown streaks may seem like it would come from the siding itself, it's usually caused by a poor attic ventilation system or leaky roofing. Here's what you need to know. 

What are these brown streaks?

Streaks are, without doubt, caused by water. Water, whether from leaks or from the accumulation of condensation, becomes discolored when it comes into contact with wood tannin. Tannin is an acidic chemical substance that binds easily to various materials, which is why it stains siding and other building materials. This is the same reason spots of water damage on your ceilings and walls are typically brown. The staining makes it difficult to clean. 

Look for signs of water damage in the attic

You'll need to do a bit of investigating to find where the water or moisture is coming from, which can help you determine what is creating the streaks on your siding. The most obvious place to start is in your attic. Look at the underside of your roofing to see if water is getting through. Pay close attention to nails. When leaking, water tends to cling to building materials and follow along until it reaches an obstacle, such as when the roofing meets the exterior wall. 

While you are in your attic, determine whether or not the temperature and humidity level are comparable to the outdoors. Attics that are properly ventilated will not be hotter and/or more humid than the outside. Too much heat and moisture inside the attic could easily result in a build-up of condensation, which will form water droplets. Check the eaves of the roof to see if the ventilation slots have gotten clogged. 

Inspect your gutters and roofing 

Also, go outside and take a look at your gutters. If they are clogged and full of water, the water may be seeping into the roofing along the edge of the roof. This problem can be compounded in the winter when the water freezes and lifts up the roofing shingles. Constant thawing and refreezing can cause additional water and ice to infiltrate through the roofing materials. This is what is called an ice dam in the roofing industry. 

While you are outside, take a close look at the shingles, flashing, vent boots, valleys, and other parts of your roofing to see if there are obvious signs of disrepair. If the shingles appear discolored, they may have lost their protective granules, which leaves them more susceptible to water infiltration. If you don't feel comfortable stepping onto your roof, hire a roofing contractor who specializes in repairing residential roofing. 

Check inside the exterior walls

Since the brown streaks are coming from the structure of your roof and home, it's important to figure out what is going on inside the exterior walls. Obviously, you don't want to tear away the walls and, fortunately, you don't have to. Hire a structural engineer or a home inspector to come and inspect the structure of your home. They will use an infrared thermal imaging system to look at the temperature differences inside the walls, which can help you pinpoint exactly where there is an accumulation of water or moisture. 

When specific areas are pinpointed by the imaging system, make note of them so you can tell the roofing contractor when he or she comes to repair the roof. That way, they will know where to concentrate their efforts if you choose to make spot repairs rather than repairing the entire roof. For more information or assistance, contact companies like Northridge Roofing.

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