maryland roofing
May 15, 2023
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Have you been diligent about keeping your roof in tip-top shape, but still noticing signs of moisture in your home? If this has you confused, your bay windows may be the culprit. If you have water stains, increased condensation, or outright leaking from your bay windows, do not fret. The right roofing professional can find the source of the leak and make the needed repairs before more damage is done to your home. Here’s why bay windows leak and what you can do to mitigate any harm to your home.

Your Home’s Material

If you’ve found leaks by your bay window, your home’s siding may be to blame. If your home has vinyl or wood siding and it is leaking, the contractor may not have used the appropriate step flashing and/or apron flashing. These types of materials require an apron flashing that overlaps the corners of your bay window. If your home’s contractor cut corners, you may start seeing signs of leaking from a lack of apron flashings or even faulty installation. The best way to remedy this is to contact a trusted roofing company for repair. This is not a job for a DIYer. Every bay window is different and a pro will know how to install the correct material to direct the water away.

Window Casings

Another reason you may see leaks near your bay window because the window casings are not sealed properly. If you notice signs of discoloration or water running down your windows, the casings must be reapplied. According to Home Guides, silicone caulk on the window’s exterior is the best sealant choice. The sides of the window frames attached to the house may also be the source of leaks and should be properly caulked for optimal sealing ability. Sealing and resealing the windows, frames, panes, and other areas connected directly to siding provides the highest level of water protection. At RoofPRO, we can provide a full inspection of your bay window to determine if the casings, siding, or windows are causing your leaks. Our contractors can reseal your windows in a timely manner and apply caulk as necessary.


Other Potential Causes

  • Improper Installation: If the bay window was not correctly installed, it could lead to gaps that allow water in. This might be due to insufficient or faulty sealant, improperly fitted window frames, or missing flashing.
  • Roof Leaks: If there’s a leak in the roof above the window, water may trickle down and enter through the top of the bay window. This is more common in bay windows that extend beyond the house’s roof overhang.
  • Damaged Window Panes: Cracked or broken window panes or damaged window sashes can allow water to leak through. The pane might be damaged due to extreme weather conditions or general wear and tear.
  • Condensation Build-up: This is common in double-glazed windows if the seal between the two panes fails. The moisture that builds up can leak out and might be mistaken for an exterior leak.
  • Lack of Overhang or Poor Drip Edge: Without a suitable overhang or well-installed drip edge above the window, rainwater can fall directly onto the window, leading to potential leaks over time.
  • Poor Drainage: If your window’s design or placement directs water towards the window rather than away from it, or if gutters and downspouts are not functioning correctly, it may lead to water accumulation and subsequent leaks.
  • Age and Deterioration: Over time, all materials degrade. Older windows may start leaking simply because components have worn out and need replacement. Regular maintenance such as cleaning the windows, gutters, and replacing the worn-out sealant can prevent leaks. Neglecting these tasks could eventually lead to water infiltration.

The RoofPRO Difference

Not only do we protect your home’s roof, we provide bay window leaking services for maximum defense against water damage. During our inspection of bay windows, we will check all flashings behind the siding for proper installation. If your home is brick, we do a full examination of the caulk around the bay window edge. We also check for missing flashing, cracking in your siding, and test the windows’ soundness. If problems are found during the inspection, our roofing pros can address those right on the spot.

To guarantee that we have addressed all leaking areas on your home, we can also perform a water test by spraying water on the bay windows. This allows us to watch for leaks in real-time. We always want to confirm that all steps have been taken to prevent the recurrence of moisture in your home.


Give us a call today to schedule a bay window repair or replacement. At RoofPRO we always offer free estimates to our Baltimore and Howard County area customers. We want to show you how a professional touch can make the difference to the structural soundness of your home.

Article Updated May 15, 2023.