Single Ply Roofing Expansion Joint Sealing: What Homeowners Should Know
Single Ply Roofing Expansion Joint Sealing: What Homeowners Should Know
Single ply roofing is a smart, durable option for flat or low-slope homes and commercial buildings alike. But one small detail often gets overlooked—and it can lead to big problems if ignored: expansion joint sealing.
At L&L Roofing & Construction, we’ve seen firsthand how unsealed or poorly sealed joints can lead to leaks, insulation damage, and costly repairs. So let’s break down what expansion joints are, why sealing them matters, and how to ensure your single ply roof stays watertight for years to come.
What Are Expansion Joints in Single Ply Roofing?
Expansion joints are intentional breaks or separations in the roof system. They’re designed to allow for movement caused by:
Temperature changes
Building settlement
Wind loads
Seismic shifts
In a single ply system—like TPO, EPDM, or PVC—these joints help the roofing membrane adjust without tearing or bubbling. But if they’re not properly sealed, water can slip in right at the weak points.
Why Expansion Joint Sealing Is Critical
Expansion joints are vulnerable zones. If left untreated or poorly maintained, they can cause:
Leaks right into your attic or living space
Wet insulation, which loses R-value and promotes mold
Membrane failure, which often voids warranties
Costly structural damage if ignored too long
And here in Gainesville and surrounding areas like Cumming, Dahlonega, and Buford, where weather swings are common, expansion joints are constantly moving and flexing. That’s why sealing is not just smart—it’s necessary.
How We Seal Expansion Joints at L&L Roofing
When our team at L&L Roofing installs or repairs single ply systems, we approach expansion joint sealing with care and precision:
1. Flexible Flashing Material
We use approved joint covers or expansion bellows made for single ply compatibility (like reinforced EPDM or TPO-compatible flashing).
2. Proper Adhesives and Sealants
No off-brand caulks here. We only use sealants rated for roofing movement and UV exposure.
3. Secure Attachment
We mechanically fasten or adhere joint covers with the right overlap and termination bars, making sure nothing lifts or flaps in high winds.
4. Regular Inspection
We always recommend inspecting joints during annual maintenance to catch cracks, UV wear, or lifting edges early.
Signs Your Expansion Joint Needs Attention
If you notice any of these, call us:
Visible cracking or gaps in the joint cover
Water staining inside the building
Bubbling or lifting membrane near the joint
Unusual roof movement or "popping" sounds
The sooner we catch it, the easier—and cheaper—it is to fix.
FAQs
How long does expansion joint sealing last?
With quality materials and expert installation, a sealed expansion joint can last 10–20 years. But we recommend checking it annually.
Can you reseal an old joint or does it need full replacement?
In most cases, resealing is possible if caught early. But if the joint or membrane is badly deteriorated, replacement may be needed.
Does every flat roof need expansion joints?
Not always. It depends on roof size, shape, and structure. But for buildings over 100 feet long or with multiple sections, joints are often essential.
Trust the Experts Who Do the Right Thing
We’re not just here to sell a roof—we’re here to protect your home and do what’s right. That means helping you understand your roof system, showing you the truth about its condition, and offering real solutions backed by integrity and faith-driven service.
Whether you’re dealing with leaks, getting ready for a roof replacement, or just want peace of mind—we’re here to help.
📞 Call L&L Roofing & Construction today at (770) 874-0372 for a free inspection or consultation.
