Understanding the Layers of Your Roofing System

When you think of your roof, you probably picture the shingles—but there’s much more to it than meets the eye. A well-built roof is a system of multiple layers, each playing a critical role in keeping your home dry, safe, and energy efficient.

At Gerken Roofing, we believe that educating homeowners is just as important as delivering top-quality craftsmanship. Whether you’re planning a roof replacement or just want to understand what’s over your head, here’s a breakdown of the key components that make up your roofing system.

1. Roof Decking (Sheathing)

What It Is: The foundation of your roof. Typically made from plywood or oriented strand board (OSB), decking is attached to the trusses and supports all other roofing layers.

Why It Matters:

• Provides a solid base for underlayment and shingles

• Needs to be structurally sound and dry before any new roofing material is installed

• If the decking is rotted or soft, it must be replaced during a re-roof

2. Ice and Water Shield

What It Is: A waterproof membrane installed in vulnerable areas like eaves, valleys, and around chimneys.

Why It Matters:

• Protects against ice dams and wind-driven rain

• Crucial in climates like Western Pennsylvania, where freeze-thaw cycles are common

• Acts as a second line of defense if shingles are damaged

3. Roofing Underlayment (Felt or Synthetic)

What It Is: A moisture-resistant barrier that covers the entire deck under the shingles. Traditionally asphalt-saturated felt, newer homes often use synthetic materials.

Why It Matters:

• Shields decking from rain if shingles are compromised

• Helps shingles lay flat and adhere properly

• Increases fire resistance and overall roof performance

4. Drip Edge

What It Is: Metal flashing installed at roof edges to guide water into gutters and protect the deck from rot.

Why It Matters:

• Keeps water from seeping behind gutters

• Required by most building codes

• Helps prolong the life of fascia boards

5. Starter Strip Shingles

What It Is: A row of specially designed shingles installed along the roof edge beneath the first layer of regular shingles.

Why It Matters:

• Seals the edge of the roof against wind uplift

• Prevents shingle blow-off

• Ensures your warranty remains valid

6. Shingles (Your Roof’s Outer Armor)

What It Is: The visible, outermost layer that provides the main barrier against weather. Gerken Roofing often installs Atlas Shingles, known for their durability and algae resistance.

Why It Matters:

• Shields your home from rain, snow, and sun

• Affects curb appeal and resale value

• Premium shingles offer longer life spans and better protection

7. Flashing

What It Is: Thin metal (usually aluminum or galvanized steel) placed around chimneys, skylights, vents, and in valleys.

Why It Matters:

• Directs water away from seams and joints

• Prevents leaks in high-risk areas

• Must be installed and sealed properly for effectiveness

8. Ridge Vent and Ventilation System

What It Is: A ventilation system that includes intake vents (soffit) and exhaust vents (ridge or gable vents) to keep your attic temperature stable.

Why It Matters:

• Prevents moisture buildup in the attic

• Reduces the risk of ice dams

• Increases energy efficiency and extends shingle life

9. Ridge Cap Shingles

What It Is: Special shingles installed at the peak (ridge) of your roof to cover the seam and complete the system.

Why It Matters:

• Seals the roof’s highest point

• Adds a polished, finished look

• Designed to be more durable and flexible than regular shingles

Why It All Matters

A roof is only as strong as its weakest layer. That’s why Gerken Roofing uses only high-quality materials and proper installation techniques at every stage of the roofing process. We don’t cut corners—because what’s under your shingles is just as important as what’s on top.

Need a New Roof or Inspection?

If your roof is aging, leaking, or has visible damage, let us take a closer look. At Gerken Roofing, we offer:

• Free roof inspections

• Honest recommendations

• Long-lasting solutions backed by warranties

Contact us today to schedule your free inspection and protect every layer of your home.