Roof flashing is like a shield for your roof’s weak spots. It’s comprised of a thin layer of durable material, typically aluminum or copper, that gets installed under shingles at critical points, including transitions like valleys and edges. These are prime locations for water to sneak through—flashing prevents this.

Think of it like the gutter system for your shingles (or other selected roofing material). These strategically placed sheets create water channels; as rain hits your roof, it flows down the shingles and reaches the flashing, which then directs the water away.

Without flashing, rain would exploit any gaps or imperfections in your roof. But what is flashing made of, and how does it work? In this blog, the experts at Black Anchor Roofing answer these questions and discuss other aspects of this critical component.

Key Functions of Flashing in a Roofing System

Flashing’s primary role within the roofing system is water management. It’s installed directly on top of the roof underlayment (waterproofing membrane) to create a continuous water barrier.

Here are a few key functions:

  • Secondary water barrier: Flashing acts as a secondary layer of waterproofing at critical transitions and penetrations on the roof, such as valleys, eaves, and around chimneys or vents.
  • Water channeling: Flashing is shaped and angled to channel rainwater away from roof junctions and towards the eaves and gutters, preventing it from pooling under shingles.
  • Sealing around penetrations: Flashing creates a watertight seal around plumbing vents, chimneys, skylights, and other elements around the roof deck.
  • Integration with drainage: For proper integration with the overall drainage system, the bottom edge of the flashing is typically bent to direct water flow toward the gutters. This prevents water from splashing against walls or fascia boards.

What Are the Different Types of Roof Flashing?

Flashing comes in various types, each designed for specific areas and functions within the roofing system.

Here are the different types of roof flashing:

Step Flashing

Step flashing is used where a roof meets a vertical wall, like an exterior wall or dormer. These are long, rectangular pieces of metal with a bent flange (lip or folded edge) that “steps” up the wall underneath the shingles to create a waterproof seal.

Valley Flashing

Valley flashing is installed in V-shaped valleys where two sloping roof sections meet. It channels water down the valley and towards the eaves, preventing it from pooling and potentially backing up under the shingles.

Counter Flashing

Counter flashing is used in a two-part system for chimneys. Base flashing wraps around the chimney base and extends under the shingles. Counter flashing is a separate piece installed on the chimney itself, with a flange that overlaps and “hooks” over the base flashing. This creates a double layer of protection.

Drip Edge Flashing

Drip edge flashing is installed along the eaves of your roof, at the edge where the roof meets the fascia board. This type of flashing prevents water from dripping directly off the roof deck and potentially damaging the fascia or siding. It also helps direct water flow towards the gutters.

Kickout Flashing

Kickout flashing is used at the end of roof-to-wall intersections, where the roof meets a sidewall and the gutter begins. It bridges the gap and diverts water away from the wall and into the gutter, preventing water damage to the siding.

What Does Flashing Repair Involve?

Since the purpose of flashing is to prevent water infiltration, the first signs of damage are often water-related issues inside your property. This can manifest as leaks or stains on your ceilings or walls, particularly near chimneys, vents, or roof valleys.

If water is finding its way past compromised material, here’s what flashing repair involves:

  1. Inspection: A professional will first inspect your roof to identify the location and extent of the damage. This may involve removing shingles or inspecting attic spaces for signs of water intrusion.
  2. Minor repairs: For small tears, gaps, or corrosion spots, the damage can often be patched with a waterproof sealant or flashing patch. If the flashing itself is still structurally sound, this is a viable option.
  3. Flashing replacement: In cases of extensive damage, loose sections, or complete failure, the affected flashing will need to be replaced. This involves removing the damaged flashing and surrounding shingles so new material can be installed and integrated with the underlayment.
  4. Sealing and re-installation: Once the new flashing is in place, all seams and overlaps are sealed with waterproof caulk or roofing cement. Then, the removed shingles are re-installed or replaced with new ones.

Common Flashing Materials

Flashing comes in different materials to suit different roof pitches, each offering unique advantages.

Here are the most common flashing materials:

  • Galvanized steel: A cost-effective option, galvanized steel flashing offers good corrosion and rust resistance but may require replacement sooner.
  • Aluminum: Lightweight, corrosion resistant, and easy to form, aluminum flashing is popular for its durability and low maintenance requirements.
  • Copper: Known for its longevity and attractive appearance, copper flashing is highly resistant to corrosion and can last for decades.

How to Check and Maintain Your Roof Flashing

The most common causes of damage to roof flashing are weather-related. Wind can lift and loosen flashing, especially around edges or valleys. Freeze-thaw cycles can cause the metal to expand and contract, stressing the seams. Meanwhile, heavy rain can overwhelm clogged gutters, causing water to back up.

Here’s how you can check and maintain your flashing:

  • Conduct visual inspections at least once a year.
  • Look for signs of deterioration, such as cracks, holes, rust, or missing sections.
  • Check for any gaps or spaces between the flashing and the roof or vertical surfaces.
  • Ensure that the flashing is securely fastened and not loose or detached.

Maintenance tasks typically include:

  • Resealing or caulking any gaps or joints in the flashing with a sealant.
  • Replacing severely damaged or corroded sections with new materials.
  • Consider upgrading to different flashing materials during roof replacements or repairs.
  • Address underlying issues that may be causing premature flashing deterioration.

Secure Your Roof With Professional Flashing Installation and Repair

The professionals at Black Anchor Roofing can protect your home from water damage with properly installed roof flashing for a watertight seal in any vulnerable areas.

Don’t compromise on your roof's integrity. Call (410) 205-9562 for professional flashing installation and repair.