A metal roof is known for its durability and long lifespan, but even the strongest roof needs a little help when it comes to vulnerable areas—like around your chimney. That’s where chimney flashing comes in. If you’re researching “metal roof chimney flashing,” chances are you’re dealing with a leak, planning a new roof, or just trying to understand how your chimney ties into the rest of your home’s waterproofing system.
So what exactly is chimney flashing, and how does it work with a metal roof? Let’s break it down.
What Is Chimney Flashing?
Flashing is a weatherproofing material installed where your roof meets a vertical surface—like a chimney or wall. On a chimney, flashing helps prevent water from sneaking into your home where the roof and brick (or siding) meet. Without proper flashing, water can travel down the sides of your chimney, damage your attic, stain drywall, and even lead to mold and rot.
For metal roofs, chimney flashing needs to be both watertight and compatible with the natural movement of metal panels. That’s why metal roof flashing is often more involved than it is on an asphalt shingle roof.
Why Metal Roof Chimney Flashing Is Different
Metal roofs expand and contract more than other roofing materials due to temperature changes. If your flashing is rigid or poorly sealed, that movement can break the waterproof barrier, causing leaks where your chimney meets the roofline.
This is why flashing for a metal roof often includes flexible materials like high-temperature sealants, rubber boots, or specially designed metal-to-brick systems. These allow the roof to move without compromising the seal.
In many cases, roofers use a multi-part flashing system that includes:
- Base flashing (sits beneath the metal panels),
- Step flashing (interleaved with metal roof panels along the sides of the chimney),
- Counter flashing (overlaps the base to seal everything in), and
- Cricket or saddle flashing (a ridge-shaped structure behind the chimney that diverts water).
Signs Your Chimney Flashing May Be Failing
Even with a metal roof, flashing can eventually wear out. If you’re seeing water stains on ceilings near your chimney or noticing rust, warping, or lifting around your chimney base, it may be time for repair or replacement.
Another sign is water pooling behind your chimney—especially if your roof lacks a proper cricket, which is vital for larger chimneys on steep-slope roofs.
Can You Reuse Chimney Flashing with a New Metal Roof?
Sometimes. But usually, no.
If you’re switching from shingles to metal or replacing an aging metal roof, your existing chimney flashing may not align with the new roof system’s specs. In most cases, roofers recommend replacing the flashing entirely to avoid compatibility issues or future leaks.
It’s a small cost compared to the price of a roof—and it’s one of the most important details for long-term protection.
Is This a DIY Job?
In theory, yes. In practice, not recommended.
Chimney flashing installation on a metal roof is highly technical, involving precision cuts, sealants rated for high temperatures, and waterproof layering that works with your roof’s pitch and panel style. Mistakes can lead to long-term leaks or voided roof warranties.
If you’re even a little unsure, bring in a professional.
FAQs About Metal Roof Chimney Flashing
1. How long does metal roof chimney flashing last?
Properly installed flashing can last 20–30 years or more, but it may wear out sooner depending on weather, roof movement, and installation quality.
2. What materials are used for metal roof flashing around chimneys?
Common materials include aluminum, galvanized steel, copper, rubberized boots, and high-temp sealants.
3. Is chimney flashing the same for all roof types?
No. Metal roofs require flashing systems that accommodate movement and temperature shifts. Shingle roofs often use simpler, more rigid flashing.
4. Do I need a chimney cricket on my metal roof?
If your chimney is 30 inches wide or more, most building codes and manufacturers recommend a cricket to divert water and prevent pooling behind the chimney.
5. Can bad flashing void my metal roof warranty?
Yes. Many manufacturers require properly installed flashing by certified professionals to maintain your roof warranty.
Final Thoughts
Your metal roof is built to stand the test of time—but chimney flashing is one of the most overlooked components of a watertight roof system. If you’re planning a roof upgrade or suspect something isn’t right around your chimney, don’t wait until water finds its way in.
Need expert guidance or want to make sure your flashing is done right the first time? Mountaintop Metal Roofing can help ensure your roof is protected throughout, so you can enjoy peace of mind for decades to come.