What is Step Flashing?

Step flashing is a type of metal flashing installed along roof-to-wall transitions, such as where a dormer or second-story wall meets a lower roof slope. Each piece of flashing is L-shaped and laid in a "step-like" sequence between every shingle course, integrating tightly into the roofing system.

This flashing acts as a diverter, forcing water away from the wall and into the shingle system, where it can be safely shed off the roof. It's made from corrosion-resistant materials like aluminum, galvanized steel, or copper.

Why This Matters

Step flashing is one of the most common sources of roof leaks — not because it fails, but because many roofers skip it, cut corners, or use undersized pieces that don’t offer proper protection.

In Maryland’s four-season climate, these areas see heavy rain, snow melt, and wind-driven water. Without robust step flashing, moisture can penetrate the roof system and cause structural rot, mold, and costly repairs.

How It Works

Each piece of step flashing is tucked under the siding or wall cladding and over each individual shingle, forming a layered water barrier. When rain hits the wall or slides down the shingles, the flashing redirects the water onto the surface of the shingle below — never letting it get behind the wall or underlayment.

It’s installed as part of a sequence:

• Shingle
• Step flashing
• Next shingle
• Next step flashing
• And so on…

This stair-step integration keeps water constantly flowing outward.

What Happens If You Don’t Use Step Flashing (or Use the Wrong Kind)

Omitting step flashing — or using small, inadequate pieces — is one of the most dangerous shortcuts in roofing.

Common problems include:

• Leaks where walls meet roofs
• Rotting wall sheathing or framing
• Mold behind drywall
• Compromised insulation
• Paint bubbling inside the home

The worst part? These leaks often go unnoticed for years — until major damage surfaces.

What Are the Types of Step Flashing?

Step flashing generally varies by:

• Material: Galvanized steel (most common), aluminum, or copper
• Size: Ranges in dimensions, often 3x3x7", 4x4x7", or custom
• Coating: Painted or raw metal, depending on visibility and corrosion resistance

Building code typically requires a minimum size (such as 4x4x7"), but many builders and roofers still use the bare minimum—or worse, skip it entirely.

What Type Does Matter Roofing & Construction Use?

At Matter Roofing & Construction, we go beyond code minimums. We install 5x5x8 step flashing on every roof — a full 25–40% larger than what most builders use.

Why does this matter?

• Wider wall coverage prevents water from sneaking behind siding.
• Longer shingle coverage ensures water drains properly into the roofing system.
• Thicker gauge metal adds durability for decades.

We don't cut corners where it counts. Every roof is protected with premium step flashing installed by skilled crews trained to do it right the first time.

TL;DR Takeaways

• Step flashing protects where roofs meet walls.
• It redirects water away from siding and underlayment.
• Undersized or missing flashing leads to hidden water damage.
• Matter Roofing uses oversized 5x5x8 flashing for better coverage and protection.
• This is one of the biggest quality differences between builders and pro roofers.