When you own or manage a restaurant, we understand that you want to focus on the restaurant and not the rooftop. Part of managing your investment is complying with NFPA 96 standards and scheduling your kitchen exhaust system cleanings according to those standards. According to the NFPA, you need to rely on a rooftop grease containment system to capture your kitchen’s airborne grease. The cleaning frequency of this system depends on your food type and output. However, if you don’t have a rooftop grease containment system installed, your investment could be at risk.

This month’s case study is from a Mexican restaurant in North Carolina, demonstrating the effects of rooftop grease contamination (see images below). At Omni Containment Systems, we see rooftop contamination at various locations. These actual jobsite photos clearly illustrate what happens when a location does not perform regular grease exhaust fan maintenance or provide a grease containment system around the fans.

The Cause

The containment system at this restaurant is too small to handle the grease output and the absorbent filters are not being changed out regularly. Rooftop grease contamination is rather obvious! As you can see in these photos, ignoring this issue opens you up to unnecessary liabilities, safety hazards, code violations, and expensive repairs or replacement.

Damaged Rooftop

Various roof systems will react differently to grease contamination, but they all have one thing in common – damage to your roof. When these fatty acids meet roofing systems, it causes them to turn soft, spongy, swell, deteriorate, and crack. The breakdown of the roofing membrane will in turn cause roof failure and leaks. These roof leaks will start off small, but eventually they will become bigger. Structural damage from leaks can put the entire building at risk.

Fall Hazards

A damaged grease laden rooftop puts maintenance workers and others at risk. Even a small grease spill on your roof can cause a serious slip and fall hazard. In this case, the grease pooled rooftop is not only causing safety issues for those on the rooftop, it can cause safety and liability concerns for people walking below when the spill starts to runoff the roof.

Fire Hazards

Did you know that rooftop grease can be just as dangerous as grease build-up in your kitchen exhaust hood? Something as small as an electrical short in a fan or even a strike of lightning can cause a grease-saturated roof to go up in flames. If a small fire ignites in the exhaust duct system, the grease pool waiting on the rooftop would compound the issue with a rooftop grease fire. Therefore, the NFPA mandates that a grease containment system be installed as a necessary deterrent.

Environmental Violations

We covered that a grease pooled rooftop can cause safety hazards, but it also carries an environmental concern. Unmaintained rooftops create grease-contaminated runoff that enters the storm water or sewer system. Rooftop grease will run off the roof and onto the sidewalks or road when it rains or snows and pollute the water when it enters the storm drains. Inspectors routinely test for code violations and can trace grease runoff to its source, meaning you could be looking at big fines from the EPA.

Voided Warranty

Grease contamination can void your roof’s manufacturer warranty. Preventative maintenance is key to keeping your warranty intact because damage caused by grease and oil contamination is not covered. This is because this damage is preventable with the correct equipment. When replacing the damaged rooftop, which can cost thousands of dollars, they may even require a sacrificial layer be installed as well, increasing your cost to repair.


At Omni Containment Systems, we want you to focus on your restaurant. Omni Containment Systems designs products that enable our clients to exceed their fats, oils and grease containment and mechanical needs with cost effective and environmentally responsible solutions. On a maintenance schedule, you can protect your facility and focus on your restaurant, not your rooftop. Contact us today to learn how we can help prevent rooftop grease contamination in your commercial kitchen!