What Is Roof Flashing and Why Does It Matter?

Roof flashing is a thin metal material that directs water away from vulnerable areas of your roof. It is the #1 cause of roof leaks when it fails. Here is what you need to know about flashing and how to keep it working properly.

Roofing 101 · 10 min read

What Is Roof Flashing?

Flashing is a thin, waterproof metal barrier installed at roof joints and penetrations to direct water away from vulnerable areas:

Location
Materials
How It Works

Types of Roof Flashing

Different flashing types serve different purposes:

Valley Flashing
Step Flashing
Pipe Boot Flashing
Drip Edge Flashing
Counter Flashing

Signs of Flashing Failure

Watch for these warning signs of flashing problems:

Rust or Corrosion
Cracks or Holes
Loose or Missing Pieces
Water Stains
Damaged Sealant

Flashing Repair and Replacement

When flashing fails, it needs to be repaired or replaced:

Minor Repairs
Section Replacement
Full Replacement

Preventing Flashing Problems

Proper maintenance helps prevent flashing failures:

Annual Inspections
Trim Overhanging Branches
Gutter Maintenance

Frequently Asked Questions

What is roof flashing and what does it do?

Roof flashing is thin metal installed at roof joints and penetrations to direct water away from vulnerable areas. It prevents leaks at chimneys, vents, walls, valleys, and eaves by creating a watertight barrier.

How often does flashing need to be replaced?

Flashing lasts 20-30 years with proper installation. Copper flashing can last 50+ years. Replace flashing when it shows rust, cracks, holes, or when sealant has failed. Annual inspections help catch problems early.

Can I repair flashing myself?

Minor sealant repairs can sometimes be DIY, but flashing work requires climbing on the roof and working with metal. Most flashing repairs should be done by a professional to ensure proper installation and watertight seals.

How much does flashing repair cost?

Minor flashing repairs cost $200-$600. Section replacement costs $400-$1,200. Full flashing replacement costs $800-$2,500 depending on the extent of damage and materials used.

Questions About Your Roof?

Schedule a free inspection with our Denver roofing team.