Metal Roof Flashing: What You Need to Know

Many homeowners are replacing asphalt shingles or other roofing materials with metal. Metal roofs last longer and have features that keep your home more energy-efficient. Just like other roofing materials, flashing is important for keeping water from getting into your home. Metal roof flashing follows the same principles as other types of roofing, but there are a few characteristics to keep in mind.


Let’s look at some of the key characteristics of metal roof flashing.


Material Compatability

Metal roofs come in various materials, including steel, aluminum, copper, and zinc. Any flashing that you install must be compatible with the metal of your roof to prevent corrosion and galvanic reactions. Typically, the best flashing for metal roofs is non-corrosive metal, but hard rubber is also a common choice.


Expansion and Contraction

Metal expands and contracts with temperature changes, and your flashing has to accommodate these changes with leaking. To allow for thermal movement, flexible materials and specialized expansion joints are common for metal roof flashing. Flashing that is too rigid can become dislodged during thermal movement, leading to leaks.


Sealants and Fasteners

Sealant is essential for any roofing material. When it comes to metal roofing, you need to use sealant that is compatible with metal roofing and can withstand thermal movement and hold up in the environment. Metal roofing also often has exposed fasteners. When attaching flashing, it’s important to use compatible fasteners that won’t corrode or compromise the integrity of the metal.


Design and Slope

Metal roofs have different profiles and shapes, most commonly standing seam or corrugated metal. Any flashing that you use must be able to accommodate these features of your roof and create a watertight seal at transitions, valleys, and penetrations, such as chimneys or vents. Metal roofs often have steeper slopes than other roofing materials to facilitate water shedding. Flashing, therefore, needs to direct water away from critical areas and ensure proper drainage.


metal roof flashing

Metal Roof Flashing | Kozy Kollar

Kozy Kollar makes flashing and vent boots that are easy to install from the inside and compatible with most roofing systems, including metal. There’s no reason to risk life and limb to install flashing when you use Kozy Kollar!


Check out our inventory of metal roof flashing, vent boots, and other products in our online store. If you have any questions about our products, feel free to contact us!