Modified Bitumen Roofing: Fixing Ponding Water the Right Way

Ponding water on a flat or low-slope modified bitumen roof isn’t just unsightly—it’s a signal that something needs to be corrected. At L&L Roofing & Construction, we’ve seen how standing water can quietly deteriorate even the most durable systems. And while modified bitumen is a strong, flexible material, it’s not immune to the long-term effects of poor drainage.

If you're seeing puddles stick around 48 hours after it rains, here's what you need to know—and what we can do to help.

Why Ponding Water is a Problem

Modified bitumen roofs are designed to shed water—not hold it. When water doesn’t drain properly, it leads to:

• Premature aging of the membrane

• Blistering and cracking

• Increased risk of leaks

• Algae or mold growth

• Voided warranties in some cases

Many homeowners don’t realize that even if there’s no leak today, the pressure and UV exposure caused by standing water can break down the membrane over time.

What Causes Ponding Water?

We’ve found several common culprits during roof inspections around Gainesville, Cumming, and Dawsonville:

• Insufficient slope in the roof deck

• Settling or compression of insulation

• Clogged or poorly placed drains and scuppers

• HVAC units or skylights installed without crickets or saddles

How We Fix It at L&L Roofing

Every solution starts with a proper inspection. Here's how we typically tackle ponding on modified bitumen roofs:

1. Evaluate the Roof Slope

The industry standard is a 1/4" per foot slope to ensure water flows toward the drain. If your deck is flat or sagging, we may recommend:

• Tapered insulation systems to restore slope

• Crickets behind rooftop units and chimneys

• Lightweight leveling compounds in localized low areas

2. Improve Drainage

We clean and inspect your scuppers, gutters, and internal drains. If needed, we can:

• Add or relocate scuppers

• Install new drains at low points

• Redirect water with custom-built crickets or saddles

3. Reinforce the Membrane

In minor ponding areas, we might upgrade your current surface with:

• Protective coatings (only if manufacturer-approved)

• Cap sheet overlays for added durability

• Localized repairs with reinforced patch systems

Important note: Many coatings can trap moisture and void warranties if not installed correctly—so always follow the manufacturer’s specifications or work with a licensed contractor.

Why Homeowners in Gainesville Trust L&L Roofing

We’ve corrected drainage issues on dozens of homes and buildings in Hall, Forsyth, and Dawson counties. Here’s why homeowners trust us:

• Honest assessments—we’ll tell you the truth, not what makes a sale

• Faith-driven service that puts people first

• Long-term solutions, not patch jobs

• Full transparency on costs and options

Like one of our Cumming clients said after a project:
“I couldn’t be more pleased. From start to finish, Luke and the crew made sure the water issues were gone—and they are!”

FAQs: Ponding Water on Modified Bitumen Roofs

Q: How long can water sit before it becomes a problem?
A: Industry guidelines consider any water that remains 48 hours after rainfall as “ponding.” That’s when damage starts becoming more likely.

Q: Can you just install a new roof over the old one?
A: Not if there’s ponding. You’ll need to address drainage first, or the problem will return—possibly worse.

Q: Will insurance cover ponding water repairs?
A: Not always. Insurance may cover damage caused by water, but not poor design or long-term neglect. We’ll help document issues clearly for your claim if needed.

Looking for honest advice on your flat or low-slope roof? Call L&L Roofing today at (770) 874-0372. We’ll tell it to you straight—and help you fix it right.