Roofing Terms 101: Simple Definitions Every Property Owner Should Know

If you’ve ever gotten a roof inspection or estimate, you’ve probably heard words like flashing, underlayment, or roof deck and thought… what does that even mean?

No matter what type of roof you have (shingles, metal, TPO, PVC), most roofs use the same basic components. Here’s a simple breakdown of common roofing terms — in plain language.

Basic Roofing Terms (Made Simple)

Roof System

Your roof isn’t just shingles or a membrane — it’s a full “system” made of layers working together to protect your home or building.

Roof Deck

The deck is the base of the roof — the surface everything is attached to.

Think of it like the “floor” of the roof.

Slope / Pitch

This is how steep the roof is.

Steeper roofs shed water faster. Low-slope roofs rely more on drains and waterproof membranes.

Underlayment

A protective layer installed under shingles or metal roofing.

It adds backup protection in case water gets past the outer layer.

Ice & Water Shield

A waterproof peel-and-stick layer placed in problem areas like:

• roof edges

• valleys

• around chimneys and vents

It’s especially important after snow/ice events.

Flashing

Flashing is metal (or membrane material) used to seal roof edges and transitions — where roofs meet walls or where things stick through the roof.

This is one of the most important parts of preventing roof problems.

Penetrations

Anything that goes through the roof is called a penetration, like:

• vent pipes

• exhaust fans

• skylights

• HVAC units

These areas need proper sealing and flashing.

Valleys

A valley is where two roof slopes meet.

Valleys carry a lot of water, so they must be installed correctly.

Gutters & Downspouts

These move water away from your building.

If they’re clogged or damaged, water can overflow and cause exterior damage.

Ventilation

Ventilation helps control heat and moisture in attic spaces.

Good ventilation can help extend roof life and improve energy efficiency.

Why These Terms Matter

Understanding basic roofing terminology helps you:

✅ know what you’re paying for

✅ understand inspection reports

✅ compare quotes more confidently

✅ make smarter decisions for your property

Need a Roof Inspection?

If you’re unsure what shape your roof is in — or you want a professional opinion — we’re here to help.

📞 Contact us today to schedule an inspection.