Leaking Commercial Flat Membrane Roof – Causes and Solutions

Keep commercial flat roof leaks from costing you valuable revenue. Your ability to identify and solve flat roof membrane issues will help keep your structure open and fully operational.

New Image Roofing Atlanta gathered information on potential commercial flat roof damage, repair, membrane types, roof maintenance program benefits, and when to call a professional roofer.

Leak Causes and Their Solutions

Commercial flat membrane roofs are known for their durability and energy efficiency. However, like all roofing systems, they are not immune to damage. A leaking roof can disrupt operations, cause structural damage, and lead to expensive repairs. Consider the following leak causes and solutions:

1. Membrane Damage

Flat membrane roofs rely on a continuous waterproof layer. Punctures, tears, or cracks can occur due to sharp objects, weather conditions, or aging.

Solution – Repair damaged areas using patching materials that match the original membrane. Consider replacing an extensively damaged membrane. Reinforce high-traffic zones with protective mats to prevent punctures.

2. Bad Flashing

Flashing seals roof edges, seams, and penetrations. Poor installation or deterioration can leave gaps, allowing water to infiltrate.

Solution – Inspect and repair flashing with compatible sealants or replace damaged sections. Ensure proper installation to withstand water pressure and thermal expansion.

3. Faulty Penetration Boots

Penetration boots protect openings for HVAC systems, vents, or pipes. Over time, they may degrade, crack, or separate, creating entry points for water.

Solution – Replace faulty boots and ensure a secure fit with the roofing membrane. Apply waterproof sealant for additional protection around seams.

4. Branch or Limb Damage

Overhanging branches or falling limbs can puncture or tear the membrane. This type of damage is more common in areas with significant tree cover or during storms.

Solution – Trim nearby trees regularly to prevent branches from contacting the roof. Repair or replace damaged sections of the membrane promptly.

5. Mold and Algae Growth

Moist conditions and debris accumulation can promote mold, moss, or algae, which degrade the roof’s surface and trap moisture.

Solution – Clean the roof using non-abrasive solutions designed for commercial membranes. Install reflective coatings or materials that resist organic growth. Ensure proper drainage to minimize moisture retention.

6. Excessive Foot Traffic

Frequent foot traffic during maintenance or inspections can lead to wear, punctures, or loosening of the membrane.

Solution – Limit roof access to trained personnel. Install walk pads to protect the membrane in high-traffic areas. Regularly inspect for signs of damage.

7. Debris Accumulation

Leaves, dirt, and other debris can clog drains and trap moisture, causing water to pool and eventually leak.

Solution – Schedule routine cleanings to remove debris. Install screens on drains to reduce blockages.

8. Ponding Water

Flat roofs are prone to ponding water, which occurs when drainage systems fail or structural sagging develops. Prolonged water exposure weakens the membrane.

Solution – Ensure proper slope and drainage during installation. Repair sagging areas and clear clogged drains. For persistent ponding, add tapered insulation to improve drainage.

Membrane Roofing System Types

Commercial flat roofs utilize various membrane systems, each with unique features and benefits:

TPO (Thermoplastic Polyolefin)

Overview: TPO is a single-ply membrane known for its energy efficiency and heat-reflective properties.

Advantages: Resistant to UV rays, punctures, and chemical exposure.
Common Issues: Seams may fail over time if improperly installed.

EPDM (Ethylene Propylene Diene Monomer)

Overview: EPDM is a synthetic rubber membrane valued for its flexibility and weather resistance.

Advantages: Durable, cost-effective, and suitable for various climates.
Common Issues: Susceptible to punctures and shrinkage.

DURO-LAST

Overview: DURO-LAST is a PVC-based membrane custom-fabricated to reduce on-site installation errors.

Advantages: Highly durable, resistant to chemicals, and easy to install.
Common Issues: This material may require specialized repairs due to its unique composition.

PVC (Polyvinyl Chloride)

Overview: PVC membranes are durable and offer excellent chemical resistance.

Advantages: Resistant to fire, wind, and water damage.
Common Issues: Higher cost compared to other systems.

Commercial Roof Maintenance Program Benefits

A proactive maintenance program is essential for extending the lifespan of a flat membrane roof and avoiding costly repairs.

Early Issue Detection – Regular inspections identify problems like punctures, ponding, or debris buildup before they cause significant damage.

Enhanced Performance – Maintenance ensures that drainage systems and waterproofing remain effective.

Cost Savings – Routine upkeep is far less expensive than emergency repairs or roof replacement.

Compliance and Safety – Maintaining your roof ensures compliance with building codes and minimizes safety risks.

When to Call a Professional Roofer

If a leak is detected, contact a professional roofing contractor immediately. Delaying repairs can worsen the damage and increase repair costs.

Accurate Diagnosis – Professionals can identify hidden causes of leaks and assess the roof condition.

Proper Repairs – Licensed roofers use compatible materials and techniques to ensure lasting solutions.

Safety – Working on a flat roof involves risks, especially during inclement weather or with extensive damage. Experts are equipped to handle these safely.

Warranty Preservation – Many membrane systems require professional maintenance to retain their warranty coverage.

Commercial Flat Roof Leaks and Solutions

In this article, you discovered why a commercial flat or low-slope roofing system can leak, how to fix it, types of membranes, maintenance plans, and when to call a professional roofer.

Early leak detection and prevention help avoid inconvenient building closures, business interruption, and severe structural damage.

Ignoring commercial flat roof damage or leaks can result in costly business interruptions, extensive repairs, and significant revenue loss.

Sources:
gsa.gov/real-estate/historic-preservation/historic-preservation-policy-tools/preservation-tools-resources/technical-procedures/types-of-flat-roofing-and-factors-affecting-its-deterioration
gccds.msstate.edu/research/altconstruction/roof/roof.pdf