The Importance of Rooftop Grease Containment for Restaurant and Kitchen Roofs

Facility managers and building owners are usually well aware of the importance of regular roof maintenance in order to get the most out of their roof system investment. All roof systems require certain preventative maintenance to ensure long lasting performance and an extended life along with required maintenance to protect your roof warranty.

However there are certain situations that call for extra roof maintenance such as roof systems that house grease emitting exhaust fans.

The grease and oil released from roof top kitchen exhaust fans is detrimental to almost any roof membrane.

Roof Grease Containment
Over 80% of food industry facilities have roof deterioration due to exhaust fan discharge

Whether your building is a food processing plant, kitchen, restaurant or manufacturing facility ignoring this issue opens you up to unnecessary liabilities, safety hazards, code violations and expensive repairs or replacement.

Effects of Roof Grease Contamination

Different roof systems will react differently to grease contamination but they all have one thing in common – damage to your roof system.

Bituminous (i.e. built-up roofs, tar and gravel) roof systems will turn soft and spongy following prolonged exposure to fats and cooking oils and eventually breakdown forming a jelly-like consistency.

Some thermoset roof membranes, such as EPDM, will swell and deteriorate when exposed to grease and fats.

EPDM seam adhesives and tapes may lose their bond and rupture leading to roof failure.

Some thermoplastic membranes will blister when exposed to grease and oil.

Grease contamination can void your roof’s manufacturer warranty. Most manufacturers will not cover damage caused by grease and oil contamination. Many roofing manufacturers will even require a sacrificial layer of membrane or coating be installed near exhaust fans that emit grease and oil.

8 of 10 restaurant roofs will require expensive repairs due to the lack of rooftop grease containment. The above photos show severe damage to roof membranes caused by exposure to grease.

NOTE: There are some thermoset and thermoplastic membranes that are more resistant to grease and oil. This can be beneficial when designing a new roof system for a restaurant or other building that expels grease on the roof. Remember however that this is only allows for extra protection against the effects of grease on your roof, you should still have a grease containment method in place.

Safety Issues of Rooftop Grease Contamination

Roof grease contamination can also cause safety hazards.

Grease and oil on your roof top can lead to fall hazards.

Grease contamination on your roof can lead to animal and insect infestation.

Grease and oil on your roof also creates a potential fire hazard which can also violate local fire and building codes.

You are risking possible EPA and code violations. Water runoff going to sewer systems or grounds adjacent to the building can be contaminated from the grease and oil.

Grease on roof
Grease on your roof can lead to slip hazards

So what do I do about grease contamination on my roof?

The best way to protect your roof is to prevent the grease and oil from ever reaching it. Should there already be grease contamination on your roof the heavy deposits should be removed and then the area either cleaned or removed and repaired with new membrane.

Prevention is really the key here. There are several methods to prevent grease and oil from damaging your roof.

Catch Pans/Collection Buckets

One method is the installation of a catch pan underneath the exhaust hoods. This method however is not very effective and doesn’t always help keep grease and oil from reaching the roof membrane. These catch units have to be checked often and emptied regularly.

Catch pans also have a bad habit of developing leaks for overflowing. When these devices fill with rainwater they can spill some grease and oil back onto the roof. Catch pans with a lid function a bit better and don’t allow rain water to enter.

We’ve even seen people attaching buckets or just setting buckets underneath the exhaust as a way to catch the overflow of grease. We do not recommend this method!

Built-in Catch Container

Most ventilators and exhaust fans have a catch container built in and is usually found under the drain spout of the fan or around the curb itself. These devices are attached directly to the unit and designed to catch the grease

The problem with this method is that these devices and not always effective due to the fact that they are difficult to clean, maintain and install.

We see many instances where they are left to overflow and a small container is then put underneath this device to catch the overflow of grease onto the roof.

Filtered Grease Containment Units

Another method to control grease contamination on your roof is the installation of grease containment system with replaceable filters such as the Grease Gutter and Grease Gutter SideKick systems from Omni Supply and Grease Terminator 2 system from Loren Cook.

These containment systems feature easy to replace filters that are designed to absorb fat based grease and oil that allow moisture to pass through while the grease remains trapped in the filter. These systems are compact as well as sturdy and less likely to be damaged by rooftop vendors.

Some filters are also contain skins that are impervious to UV rays as well as treated with enzyme neutralizers that reduce the destructive acidic properties of grease to further protect your roof. These types of systems are easy to install and maintain.


All of these methods work while some require more regular maintenance than others. If you are a high capacity kitchen using lots of cooking grease you may want to choose a higher capacity system such as the High Capacity Grease Gutter. For others just a catch pan may do the trick.

But as you can see there is still a need for regular maintenance with any of these methods. Any roof that houses units that emit any substance onto the roof should be a high priority and checked regularly. Any grease containment systems should be checked regularly to ensure proper performance. Grease traps and pans need to be emptied regularly, grease filters need to be replaced at least twice a year.

Again we can’t say this enough… Regular roof maintenance is the key to a longer roof life and better performance!

With such an expensive asset at stake the minor costs of regular maintenance always outweigh the cost of unnecessary repairs and early roof replacement. You wouldn’t buy and expensive car and then never have the oil changed so don’t ignore your roof.

Interested in having a grease containment system installed on your roof?

Need repairs completed to damages already caused by grease contamination? Contact Jurin Roofing Services today!

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