Single-Ply Roofing Expansion Joint Sealing: A Practical Guide

Expansion joints are a crucial part of commercial roofing—especially in single-ply systems like TPO, PVC, and EPDM. If you own or manage a commercial building in Colorado or Georgia, understanding how and why to seal these joints properly can prevent major problems and extend the life of your roof.

Here’s what you need to know.

What Are Expansion Joints in Roofing?

Expansion joints are designed to absorb movement caused by:

• Thermal expansion and contraction

• Seismic shifts

• Wind sway

• Structural settling

These joints separate sections of a building and allow for independent movement. Without them, roofs can crack, wrinkle, or tear—especially in large structures or where different materials meet.

Why Sealing Expansion Joints Matters

When expansion joints aren’t sealed properly, several issues can arise:

• Leaks: Unsealed joints are vulnerable entry points for water, especially in freeze-thaw climates like Colorado.

• Membrane stress: Movement without accommodation can cause membrane failure.

• Energy inefficiency: Gaps at the joints can allow conditioned air to escape, increasing energy bills.

• Premature failure: Neglecting proper joint sealing can drastically reduce your roof’s lifespan.

Best Practices for Sealing Expansion Joints

1. Choose the Right Materials

• Flexible termination bar systems

• Pre-manufactured bellows-type expansion joint covers

• Non-curing sealants compatible with TPO/PVC/EPDM

Always follow manufacturer specs and make sure materials are UV-resistant and rated for your climate zone.

2. Ensure Proper Overlap

• Flashing and joint covers should overlap the roofing membrane sufficiently to prevent capillary water entry.

3. Mechanically Secure Where Needed

• Use fasteners and plates when required to prevent uplift—especially in high-wind areas like Colorado Springs or Savannah.

4. Inspect Annually

• Expansion joints should be checked at least once a year and after any major storm. Look for:

  • Separation of joint covers

  • Sealant failure

  • Cracks in adjacent membrane

Common Mistakes to Avoid

• Using rigid materials that can’t accommodate movement

• Skipping primers or adhesives required by manufacturer specs

• Forgetting to terminate and seal membrane edges at joints

• Combining incompatible materials (e.g., TPO with asphalt-based sealant)

Ideal for Flat Roofs in These Conditions

• Commercial warehouses in Denver

• Retail buildings in Augusta

• Schools in Aurora or Athens

• Churches or hospitals with wide-span roofing structures

FAQs

How often should expansion joints be resealed?
Most require re-evaluation every 5–10 years, but annual inspection is key. Colorado’s freeze-thaw cycles can wear materials faster.

Can expansion joint failure void my warranty?
Yes. Many manufacturers require proper joint sealing to maintain warranty coverage.

Is this a DIY job?
No. This work should always be handled by a qualified commercial roofer with membrane-specific expertise.

Trust Roof Nuts for Expert Roofing in CO and GA

Whether you're dealing with PVC, TPO, or EPDM, Roof Nuts has the know-how to properly seal and maintain your expansion joints. We work across:

• Denver, Colorado Springs, Aurora

• Atlanta, Augusta, Savannah

• And many more cities in Colorado and Georgia

📞 Colorado: 303-276-2403
📞 Georgia: 404-476-6851
🌐 Visit RoofNutsCO.com | RoofNutsGA.com

Let us help you prevent costly damage and protect your investment for the long haul.