Should You Worry About Ponding Water On A Flat Roof?

Roof ponding is a common issue that, if left unaddressed, can lead to severe damage and costly repairs. Our custom guide will help you understand:

• What roof ponding is
• Why it occurs
• How you can prevent and remedy it

Whether you’re a building owner, facility manager, or roofing professional, you’ll gain valuable insights to maintain the integrity of your commercial roof.

What is Roof Ponding?

Roof ponding occurs when water accumulates on a flat or low-sloped roof and does not drain or evaporate within 48 hours after a rainfall. While a small amount of standing water is occasionally inevitable, persistent ponding water can cause significant damage to the roof structure and building.

Why is Roof Ponding a Problem?

Roof ponding can cause all sorts of issues for your commercial roofing system, including:

• Structural Damage: Over time, the added weight of ponding water can stress and potentially weaken the roof deck and support structure. This can lead to sagging, cracks, and even roof collapse in extreme cases.
• Membrane Deterioration: Water accumulation can degrade the roofing membrane, especially if the water is laden with contaminants. Prolonged exposure can cause blistering, splitting, and other forms of deterioration.
• Increased Risk of Leaks: Standing water increases the likelihood of leaks, as water seeks the path of least resistance. Even a tiny gap or seam can allow water to penetrate the roof system, causing damage to insulation, electrical systems, and interior finishes.
• Algae and Mold Growth: Water ponding creates an ideal environment for algae and mold growth, which can further damage the roofing material and pose health risks to building occupants.
• Decreased Insulation Efficiency: Waterlogged insulation loses its thermal resistance properties, leading to higher energy costs and reduced indoor comfort.

Common Causes of Roof Ponding

Understanding the root causes of roof ponding is crucial for effective prevention and remediation.

• Poor Roof Design: Flat and low-sloped roofs are more susceptible to ponding due to their inability to naturally shed water. Inadequate slope design or insufficient drainage systems can exacerbate the problem.
• Clogged Drains and Gutters: Even a well-designed roof can experience ponding if the drainage systems are clogged with debris, leaves, or ice. Regular maintenance is essential to ensure water flows freely off the roof.
• Structural Settling: Over time, buildings can settle unevenly, causing depressions or low spots on the roof where water can accumulate. This is particularly common in older buildings.
• HVAC Units and Other Equipment: Rooftop equipment such as HVAC units, vents, and solar panels can obstruct water flow and create isolated areas of ponding.
• Membrane Issues: Improper installation or aging of the roofing membrane can lead to wrinkles, blisters, and other deformities that trap water.

6 Prevention Strategies for Roof Ponding

Taking proactive measures can help prevent roof ponding and extend the lifespan of your commercial roof.

1) Ensure Proper Roof Design

When constructing a new roof or replacing an existing one, ensure it has an adequate slope (at least 1/4 inch per foot) to facilitate water drainage. Consider using tapered insulation or structural slopes to achieve the desired pitch.

2) Install Effective Drainage Systems

Incorporate a comprehensive drainage system that includes roof drains, scuppers, and gutters. Ensure these systems are correctly placed to handle the expected volume of water. Regularly inspect and clean drains and gutters to prevent blockages.

3) Regular Roof Maintenance

Implement a routine maintenance schedule that includes inspecting the roof for signs of ponding, clearing debris, and checking for any damage to the membrane or structure. Address any issues promptly to prevent them from escalating.

4) Use Quality Roofing Materials

Invest in high-quality roofing materials designed to withstand prolonged exposure to water. Consider materials with superior UV resistance and durability, such as thermoplastic polyolefin (TPO) or ethylene propylene diene monomer (EPDM) membranes.

5) Reinforce Low Spots

If the roof has low spots prone to ponding, reinforce these areas with additional layers of roofing material or install crickets (ridge structures) to divert water toward the drains.

6) Monitor Rooftop Equipment

Ensure that rooftop equipment is installed with proper clearance and does not obstruct water flow. Regularly inspect and maintain equipment to prevent leaks and damage.

Remediation Techniques for Existing Roof Ponding

If your roof is already experiencing ponding, several remediation techniques can help resolve the issue and prevent further damage.

• Re-leveling the Roof: For significant ponding issues, re-leveling the roof may be necessary. This process involves adding layers of insulation or roofing material to create a new slope and improve drainage.
• Installing Additional Drains: Adding extra roof drains or scuppers can enhance water removal and reduce ponding. Ensure that new drains are strategically placed to address low spots and areas prone to water accumulation.
• Applying Roof Coatings: Roof coatings can provide an additional waterproof layer and improve the roof’s resistance to ponding water. Silicone or acrylic coatings are popular options due to their durability and reflectivity.
• Implementing Temporary Solutions: In some cases, temporary solutions such as using sandbags or portable sump pumps can help alleviate ponding until a more permanent fix is implemented. These solutions should only be used as a stopgap measure and not a long-term solution.
• Engaging Professional Help: If roof ponding persists despite your efforts, it’s essential to seek professional assistance. A qualified roofing contractor can assess the situation, identify the underlying causes, and recommend appropriate remediation techniques.

The Importance of Regular Roof Inspections

Regular roof inspections are crucial for identifying and addressing ponding issues before they escalate. Consider the following best practices for effective roof inspections:

️ Schedule Routine Inspections

Conduct roof inspections at least twice a year, ideally in the spring and fall, to identify any signs of ponding, damage, or wear. Additionally, inspect the roof after significant weather events such as heavy rainstorms or snowfall.

‍♂️ Use Professional Inspectors

Engage professional roofing inspectors with the expertise and experience to identify potential problems and recommend appropriate solutions. Professional inspections provide peace of mind and ensure that all issues are thoroughly addressed.

Document Findings

Maintain detailed records of each inspection, including photographs, notes, and any recommended actions. This documentation can help track the roof’s condition over time and support warranty claims if necessary.

⏰ Address Issues Promptly

If ponding or other issues are identified during an inspection, take immediate action to address them. Promptly implementing preventive measures or remediation techniques can prevent minor problems from becoming major headaches.

Expert Service For Flat Roofs

Roof ponding is a significant concern for commercial building owners and facility managers, but it is manageable with the right knowledge and proactive measures. Regular maintenance, quality materials, and professional assistance are key to mitigating the risks associated with roof ponding. Follow the guidelines outlined in this guide, and you’ll be well-equipped to maintain a healthy, durable, and efficient commercial roof.

For more information on commercial roofing solutions or to schedule a professional roof inspection, contact Greentek Roofing today. Your roof’s health is our priority, and we’re here to help you every step of the way.