Importance of Rooftop Grease Containment

Commercial food establishments, like restaurants, cafes, hospital kitchens and coffee shops, have a critical need for exhausting the air from their kitchens. This hot air, being contaminated with grease, comes from dishwashers, ovens, stoves and grills. The way out is often through the rooftop.Rooftop-Grease-Containment

The smoky, grease-laden air from commercial kitchens is expelled into ducts that lead out to the roof. In time, the smoke, grease and kitchen odors contaminate the rooftop. Depending on what type of commercial roof is in place, extensive rooftop damage is the inevitable outcome.

What Type of Roof Damage Occurs?

Significant greases and oils that pervade a rooftop lead to a severe shortening of the roof’s lifespan. Property owners will be hit with thousands of dollars’ worth of premature roof repairs or will face the need for a complete and expensive roof replacement.

Property managers who oversee a building with a bituminous roof will notice that exposure to the greases vented out of the roof’s exhaust system cause the roof to become soft and spongy. Eventually, the bituminous roof assumes a consistency similar to jelly.

Synthetic rubber roof membranes, like EPDM (a subcategory of thermoset roof membranes), undergo swelling and deterioration when exposed to smoke, oils and greases. The seams of these EPDM roofing systems will rupture or lose their ability to bond, leading to a disastrous roof failure.

What are the Additional Issues of Grease Contamination?

Expect the roof manufacturer’s warranty to be voided, since most manufacturer’s will simply not cover the avoidable ruin caused by oil and grease saturation. Property owners will end up paying hefty costs for roof repairs or even for a total roof replacement.

Employee safety is sacrificed. Staff who climb ladders to perform routine maintenance along the roof are at a high risk for slipping and falling, due to the slick presence of greases and oils. As a result, property owners are met with employee liability issues.

Grease catches fire and burns easily. The risks for fire hazards spike when grease saturates the rooftop. One small spark, electricity short or even a random lightning strike will send the grease-laden roof and the building below up in a bellow of flames within seconds.

What are Best Practices to Protect the Roof from Grease?

Grease containment is the most effective way to prevent the oils and smoke from reaching the roof’s membrane—and avert all the adverse results associated with grease contamination. Along with installing a grease containment system, regular inspections and maintenance of the system are required.

When greases and oils already saturate the roof, the contaminants should first be removed. The rooftop subsequently should be thoroughly cleaned. Once clean, the rooftop should be fitted with a new roofing membrane. Repairs like these are expensive, making prevention the most cost-effective measure.

What are Grease Containment Options?

The most effective way to prevent grease buildup on the roof is to install a filtered grease containment unit. The system features replaceable filters that catch grease and oils, while allowing moisture, such as rainwater, to pass through. The grease remains inside the filter.

Another excellent method to prevent grease contamination is to install a self-extinguishing fiberglass filter. The system, while repelling rainwater, absorbs grease. An aluminum frame sustains the filter. The unit’s fireproof barrier protects the roof from possible fires in the exhaust system.

Additionally, off-the-roof grease containment systems are mounted on legs off the roof. Precipitation passes through the filters, leaving the multi-layered filters to absorb the grease and oils. The filters do not absorb the rainwater and instead fully capture the fats and greases.

Built-in catch containers may exist in the exhaust fans or ventilators. Attached beneath the drain spout, the containers catch emitted greases. Due to the fact that built-in catch containers are a challenge to install, regularly clean and may overflow, this route does not promise full efficacy.

Rainproof systems are essential. Rainwater may be captured in a grease containment system, along with the grease, enabling an overflow. The outpouring of grease and water only contaminates the roof, leading to potential roof and building fires, as well as significant roof damage.

Routine maintenance and regular inspections of any grease containment system are as necessary as installing the unit in the first place. Without timely filter changes, the grease container will be unable to perform its critical task of capturing grease and trapping it. Change filters at least twice annually.

In a high output commercial kitchen, a high-capacity grease containment system may be necessary. Alternately, a smaller output may do well with a catch pan, which is simply a pan located under the exhaust hood. Catch pans easily overflow with both grease and rainwater, making them ineffective.

Install the Proper Membrane

Grease is essentially a solvent.  When hot grease and oil land on your roofing membrane, that solvent nature over time degrades the roof system.  Installing a grease resistant membrane, such as PVC is the most effective way to combat grease that does escape a containment system and land on the roof.  PVC roof membranes have been shown to have the best chemical track record in holding up t the harsh environment of commercial kitchen roofs. 

Work with a Commercial Roofer

When you are faced with a damaged roof due to such unwanted scenarios as grease contamination, consult a professional roofer to tackle the ruin. Reliable Roofing provides prompt and comprehensive roofing services that address every level of roof wear and tear.

The experts at Reliable Roofing are proficient in commercial roof repairs, commercial roof replacement and roof construction, among a host of other roofing services. Our roofers have experience with commercial properties, like restaurants, warehouses, retail store and hospital facilities.


As a fully licensed, bonded and insured roofing contractor, Reliable Roofing offers maximum peace of mind to its customers. Partnering with the best manufacturers in the industry, Reliable Roofing works only with the highest quality roofing materials, ensuring excellence and dependability.

Get a Free Estimate

Reliable Roofing offers a free estimate and a team of specialists who are ready to answer all your questions about roofing issues. When you seek excellence in workmanship, cost-effective services and a roof that is built to withstand the elements and time, Reliable Roofing will meet your roofing needs.

Give us a call at (815) 981-9898 for a free estimate.