Single-Ply Roofing Curb Flashing: What Homeowners in Gainesville Need to Know

If your home or business has a single-ply roof—like TPO or PVC—you probably already appreciate the clean look, energy savings, and durability these systems offer. But one critical detail often gets overlooked: curb flashing.

Whether you're protecting a skylight, a rooftop HVAC unit, or a vent, curb flashing is what keeps water from seeping into your building around those roof penetrations.

Here’s what you need to know to keep your roof sealed tight and your home safe.

What Is a Curb in Roofing?

A roof curb is a raised frame—typically made of wood or metal—that supports rooftop equipment like:

• HVAC units

• Skylights

• Exhaust fans

• Vents

On flat or low-slope roofs, these curbs stick up above the main membrane. That makes them vulnerable to water intrusion if not flashed correctly.

What Is Curb Flashing?

Curb flashing is the waterproof seal around the base of that raised curb.

On single-ply roofs like TPO, EPDM, or PVC, the flashing is usually made from the same membrane material, often heat-welded or adhesively bonded to the vertical and horizontal surfaces.

A proper curb flashing setup includes:

• Base flashing: Wraps up the sides of the curb

• Membrane welds: Seals the flashing into the main roof system

• Counterflashing (optional): Protects the upper edge, especially for HVAC or metal curbs

• Termination bar or cover strip: Keeps the top edge secure

Done right, curb flashing channels water away from seams and into the roof drainage system.

Why It Matters in Gainesville, GA

North Georgia weather throws a lot at your roof:

• Heavy rain in spring and summer

• Strong winds and storms in fall

• Occasional hail and freezing temps in winter

Poor curb flashing leads to leaks that show up as:

• Water stains on ceilings

• Moldy smells in HVAC systems

• Rotting roof decking around curbs

• Electrical damage to equipment

At L&L Roofing, we’ve seen firsthand how neglected or incorrectly flashed curbs can shorten the life of a single-ply roof. That’s why we always follow best practices—using proper membrane attachment, full seam welds, and tight seals around every penetration.

FAQs About Curb Flashing

How long should single-ply curb flashing last?
With quality materials and installation, flashing should last the life of the roof—usually 20–30 years. But poor workmanship can lead to failure in just a few years.

Can curb flashing be repaired or does it need replacing?
If caught early, isolated damage can be heat-welded or patched. But if the flashing is pulling away or improperly installed, full replacement is the better option.

How do I know if my curb flashing is failing?
Signs include pooled water around curbs, interior leaks near equipment, bubbling or lifting membrane edges, or visible gaps in the seal.

When to Call L&L Roofing

If you own a home or business in Gainesville, Cumming, Flowery Branch, or Dawsonville, and your roof has any equipment curbs, it’s a good idea to:

• Have us inspect your roof once a year

• Check the curb flashing if you’re seeing leaks near HVAC systems or skylights

• Schedule a repair quickly if you notice lifted seams or damaged flashing

We’ve helped customers all over north Georgia protect their homes with faith-driven service and quality craftsmanship. Our team knows the difference between a quick patch job and a long-lasting solution—and we always choose what’s right.

Need expert curb flashing repair or a full roof inspection?
Call L&L Roofing & Construction at (770) 874-0372 and let us help protect what matters most.