Expert Tips to Identify and Prevent Roof Flashing Leaks

If your home is suffering from a trickling roof, you’re likely scrambling to identify the source of the leak to prevent further damage to your attic, drywall, and furniture.

Roof leaks can be caused by various issues, like broken shingles, vent cracks, poorly sealed valleys, and more. However, the majority of roof-related leaks occur at the flashings.

We created this thorough guide to help you understand the source of roof flashing leaks, how to fix them, and most importantly, how to prevent this pesky issue from happening again.

What Is Roof Flashing?

Roof flashings are strips of metal or rubber that create a waterproof barrier for transition areas on your roof, like the chimney, skylights, vents, and dormers.

Flashings can be made from copper, galvanized steel, tin-plated steel, or lead, and they are typically sealed with roof mastic and modified bitumen or fiber membrane to create a water-resistant barrier.

What Causes a Roof Flashing Leak?

Unfortunately, roof flashing leaks are common and can be caused by several factors.

First, the sealant may begin to corrode and deteriorate over time, exposing vulnerable areas of your roof to the elements.

Second, the source of the leak may be shoddy construction. Typically, this happens when your roofer fastens the flashings using standard caulk or roofing cement, which causes the seal to deteriorate rapidly from the sun's UV rays. It may also happen when the metal strips are nailed down incorrectly, which can cause them to slide.

Lastly, powerful storm damage, like heavy rain or strong winds, can cause your flashing to break, move, or pull away from your roof.

How to Identify a Roof Flashing Leak

It's crucial to confirm that your flashing is the leak's source before investing in repairs.  

One foolproof way to identify a flashing leak is a two-person job you can complete on your own. Send someone up to your attic, then carefully climb a ladder onto your roof with your garden hose. Call the person in your attic on their cell phone, then begin gently running water from the hose onto the areas of your roof that intersect, like the chimney, skylights, and vents. If the person inside your attic can verify water infiltration when the hose is running over a particular spot, you know you need to get the flashing repaired in that location.

If you don't feel comfortable climbing onto your roof, contact a roofer to complete a thorough inspection of your flashings. Even if you do identify a leak, it's wise to have a contractor inspect your roof to determine if your flashing needs to be replaced or just repaired.

Steps to Repair Loose Flashing

You may feel like you can reattach your flashing on your own, but we recommend hiring a contractor to do the job. Some roof flashings can be easy to install, but others require the right skills, tools, and experience to position correctly. Additionally, incorrectly attached flashings or low-quality sealants will just cause more leaks down the road.

Your contractor will complete the following steps to repair your chimney flashing:

• Remove debris between the flashing and chimney
• Scrape away sealant remnants with a chisel
• Apply roof mastic behind the flashing
• Attach the flashing tightly with nails or screws
• Cover exposed nails with roofing mastic
• Apply roof mastic between the flashing and roofing material
• Smooth roof mastic with a putty knife

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How Do I Know If My Flashings Need to Be Replaced?

Sometimes, your flashings are too damaged to be repaired and require a complete replacement. Usually, you'll need to invest in new flashings if your old ones are:

• Missing or broken
• Rusted
• Completely separated from the roof
• Covered with roofing tar (a temporary fix that usually harbors underlying issues)

To prevent flashing leaks, have your roof inspected every six months. And as a general rule of thumb, even if they’re still in great shape, you should also replace your flashings while replacing your shingles so that they will last as long as your new roofing system.

Identify Roof Flashing Leaks with Our High-Tech Roof Inspection Process

If you inspected your roof and found loose flashing, or even if you suspect you may have a flashing leak, we can help you get to the root of the issue.

At American Way Exteriors, we use state-of-the-art technology to perform drone roof inspections. This safe, convenient process includes a quick five-minute assessment of your roof to identify issues you may not be able to spot on your own. Learn more about how our high-tech roof inspection process gives our team expert insight on how to remedy your flashing leaks and roof damage, once and for all!