When most homeowners think about their roof, they picture the shingles. While shingles provide the primary layer of protection, they cannot protect your home alone. Every roof has transition points—areas where the roof meets a wall, a chimney, or a valley—where shingles cannot create a watertight seal. This is where roof flashing comes into play.
Serving Denton County and the DFW area, we have found that flashing failure is one of the most common causes of interior water damage. Understanding what this material is and how it functions can help you spot potential issues before they lead to an expensive roof repair.
What is Roof Flashing?
Roof flashing is a thin material, usually made of galvanized steel, aluminum, or copper, that redirects water away from critical areas of the roof. Its primary job is to bridge the gap between different materials or surfaces to ensure water continues to flow down toward the gutters rather than seeping into the roof deck.
In the North Texas climate, flashing must be durable enough to withstand extreme temperature fluctuations. On a 100-degree summer day in Denton, your roof surface can reach temperatures far higher than the air. The metal must be installed in a way that allows for slight expansion and contraction without breaking the seal. At DKG Roofing, we prioritize using heavy-gauge materials that stand up to the high winds and heavy rain common during our spring storm seasons.
Common Locations for Flashing
A roof is rarely one flat surface; it is a series of planes and penetrations. You will find flashing in several key areas across your property:
Chimneys: This is the most common leak site. Chimneys require four components: apron flashing at the bottom, step flashing on the sides, and a cricket or backer flashing at the top, all topped with counter-flashing embedded into the brick mortar.
Valleys: Where two roof slopes meet to form a 'V' shape, a massive amount of water is funneled through. W-valley or open-metal flashing ensures this high-volume runoff doesn't find its way under the shingles.
Dormers and Side Walls: Anywhere a vertical wall meets the roof plane, step flashing is required. These individual L-shaped pieces of metal are "stepped" up the roof with every course of shingles to create a waterproof barrier.
Vents and Pipes: Plumbing vent pipes and exhaust fans use 'boots' or collar flashing to prevent water from running down the exterior of the pipe and into your attic.
Why Flashing Fails in North Texas
DFW weather is particularly hard on metal components. Between thermal expansion from the sun and the physical impact of hail, flashing can lose its integrity over time. One of the most common issues we see during a roof inspection is "backed-out" nails. As the wood and metal expand and contract at different rates, nails can sometimes pop up, creating a hole for water to enter.
Furthermore, older homes may have flashing that has simply rusted through or was improperly sealed with roofing cement rather than being integrated into the structure. As a veteran-owned company, we take pride in doing things the right way the first time—meaning we use proper mechanical bonds and high-quality sealants that are designed for the Texas heat.
The Importance of Proper Installation
Flashing is not a "one size fits all" product. It must be custom-bent and fitted to the specific angles of your home. If a contractor cuts corners by reusing old, battered flashing during a new roof installation, you are essentially putting a "used" part on a new machine. It is the weakest link in your roofing system.
Ensuring your flashing is correctly layered (or "shingled") is vital. The upper piece must always overlap the lower piece so that gravity works with you, not against you. If you suspect your flashing has been damaged by a recent storm or if you notice rust streaks on your shingles, it is time to have a professional take a look.