How to Fireproof Green Roofs? [Ultimate Guide]

Green roofs are vegetated roofs with benefits. They reduce energy consumption, improve air quality, and mitigate stormwater runoff. However, one of the main concerns about green roofs has been their fire safety.

What can you do to make it safer and protect your investment in a more environmentally friendly future? In this post, we will cover everything you need to know about how to fireproof green roofs.

Before we delve into any further, this post is not meant to be an exhaustive guide on green roof fire safety. Always consult with a professional before undertaking any work on your roof, and always follow all local city ordinances and building codes.

Let me ask you a few questions:

  • How safe do you think your roof is without even having a component of a green roof?
  • Is there anything combustible on your roof?
  • Is there any equipment that could cause a fire that is not improperly wired or maintained?
  • Is there anyone smoking on your roof?
  • When was the last time a fire safety or hazard assessment was performed on your roof?

The reason I am asking these questions is to make you think if you are aware of what exactly is happening on your roof. Many building owners and managers aren’t aware of very simple facts about their roofs.

Fire Extinguisher on the wall

When it comes to fireproofing a green roof, there are many improvements that can be made.

Some of them are very self-evident and can immediately improve the fire safety of your roof. For example, something like removing all combustible materials from the roof is a good place to start.

However, some of the measures you must take may necessitate the assistance of a professional. For these types of measures, you would need to contact a qualified fireproofing contractor.

Because they can assist you with a variety of fireproofing measures, they are the best people to help you assess your roof and put together a plan tailored specifically for your building.

Once you have a fire safety plan for your green roof, you can begin implementing it. This is not something you want to do on the fly. You will need to document everything for future reference. Because you may be required to provide this information by law or insurance requirements in the future.

Therefore, I would highly recommend recording the fire safety measures you have taken. Keep all receipts for material and labor costs to help back up your claims. Take time-stamped photos and videos of the roof and all measures you have undertaken. You never know when this information might come in handy.

The bottom line is that you have to act according to a plan. And all stages of the implementation must be documented. By doing so, you not only reduce the chance of a fire but also the potential compliance costs that could be very hefty.

That said no measures that are taken can guarantee 100% fire safety. There is always some fire safety risk with any roofing system. But by implementing a step-by-step that suggests best practices, you can bring your building closer to that goal.

Further in this post, we will look at some of the most common causes of fires on green roofs and some preventative measures you can take to minimize those risks.

What are the reasons that green roofs catch on fire?

Because of their organic nature, green roofs are more flammable than other types of roofs. They have a lot of plant matter and vegetation in them, which is highly combustible if it gets dry enough.

Here are the most common causes of green roof fires:

Improper Installation

Proper installation of roofing systems is critical to their overall fire safety. Green roofs are made up of many elements, including layers of waterproofing materials, insulation mats, and drainage grates.

Since green roofs are exposed to harsh conditions, including full sunlight and high wind speeds, they are susceptible to damage. This can happen during installation or soon after if proper care is not taken when installing these systems.

For example, the growing medium used on the roof can get dry if exposed to sunlight.

This can cause heat buildup under the insulation layer of mats and create an environment for a fire to start. To prevent this, it is important to make sure that the growing medium is kept moist especially during the hot summer months.

Similarly, the wind can pick up loose debris from the plants and carry it next to the mechanical equipment which can lead to electrical shorting and a fire. These are just a few examples to show how easily something like this can happen.

Electrical faults

Electrical faults are very common. They can happen for many reasons including wiring problems, overloaded circuits, and faulty equipment.

Electric Fault Circuit Switch

However, when an electrical fault combined with the existence of a green roof can create additional risks for fires. For example, if an electrical fault occurs on a green roof, the fire has a better chance of spreading because of the increased combustibility of the vegetation.

As with any building, the risk of an electrical fire increases as the amount of wiring and electronic equipment increases. This can become a serious problem if the wiring is not properly protected and is located in close proximity to the growing medium.

One of the most common causes of an electrical fire on any roof is when rain or snow contact wiring that is not properly protected from the elements. This can create a short circuit and start a fire.

Another common cause of fires due to electrical faults is overheating caused by overloaded circuits. This can happen when there are too many devices drawing power from a single circuit.

And, finally, faulty equipment is always a potential fire hazard. This includes everything from light fixtures to air-conditioning units. When these units fail, they can overheat and start a fire.

Avoid using extension cords on your roof permanently, and if you will use make sure they are grounded. Also, prefer only UL-listed power strips with built-in circuit breakers.

Since the roof is a potentially wet area, it’s important to make sure that all electrical equipment is properly grounded. Use electrical appliances that are GFCI protected. This allows you to use them in wet areas and they will trip and shut off if they come in contact with water.


This one is pretty self-explanatory. Smoking on or near any roof can easily start a fire. But it’s especially dangerous to smoke on a green roof because the vegetation can quickly spread the fire.

man smoking on roof

Therefore, smoking is extremely irresponsible and should not be done on any green roof.

Some building projects may want to install allocated smoking areas on their roofs to allow occupants to smoke without compromising health and safety. But, this is an exception and should only be done after careful consideration of the risks involved.

In all cases, the combustible materials/liquids must be securely stored in designated cabinets in accordance with NFPA/OSHA rules.

Growing medium content

The growing medium is the layer that supports and nourishes the plants on a green roof. It is made up of many different materials including synthetic and organic compounds to support the plants that live there.

coconut substrate pressed
Pressed coconut substrate for gardening

If the growing medium is too dry, it can become combustible. This means that if a fire starts nearby the growing medium can easily ignite and start a fire.

This is why it’s so important to make sure that the growing medium stays moist, especially during hot and dry weather conditions.

Another issue with the growing medium is its content. Although it consists of different materials, it is generally made up of soil, wood chips, peat moss, and fertilizers.

The organic content in many growing mediums can create a fire hazard. Therefore, the content of the growing medium should be designed carefully to reduce the risk of an uncontrollable fire.

According to the GRO Green Roof Code, the organic content in a growing medium should not exceed 20% for effective fire prevention. Plants like succulents are highly recommended. Because they retain water within their structure and lower the risk of the substrate drying out.

succulents in garden

The ANSI regulation also refers to fire-resistant vegetative systems as “succulent-based” and “grass-based,” with the growing substrate including at least 80% inorganic matter in both cases. The non-vegetative components of the roofing must be ASTM E108 Class A systems.

Wind design

Winds pose a serious threat to green roof safety because they can cause and spread roof fires. It’s extremely important to take precautions against high winds when designing and building green roofs because they can quickly become disasters if left unchecked.

Wind Damage

Most buildings are designed without paying much attention to the wind loads. However, regional wind speeds and gusts must be taken into account when designing a green roof.

Exterior fire rating

Building codes provide the standards for the fire resistance of the roofing system depending on the designated occupancy. Roofing systems may be needed to meet ASTM E 108 Class A, B, or C standards.

Provisions must be made to ensure that the vegetation put on the roof has long-term resistance to the spread of fire, as required by the building code.

Selection of vegetation

Some plants, such as succulents, are extremely resistant to fire. When fire-resistant vegetation is established, local code officials may consider relaxing the barrier restrictions.

Vegetative roofing systems can be tested using ASTM E-108 and UL 790 standards. Modifications to the test standards may be able to produce a relevant test for certain conditions.

However, with all of the plant types that could be employed in a roof design, the varied weather conditions that occur throughout the year, and the influences of seasons generate many elements that limit the potential to classify a roof construction.

As a result, if the roof is designed with little or no maintenance in mind, fire-rated barriers are required.

Given that wind requirements frequently necessitate larger portions of non-vegetative roofs, the size of the perimeter area or border zones is frequently determined by the wind standard.

Poor maintenance

Maintenance is one of the most influential factors in green roof durability and fire safety. If maintenance requirements aren’t met, vegetation dries out, the growing medium can ignite, and a fire can quickly spread.

All too often, building owners or managers don’t understand the importance of routine maintenance until it’s too late.

It is also not about the maintenance of the green roof but of all building systems. Poor maintenance of the building systems especially energy systems can lead to disaster.

The best way to ensure that a green roof is safe is by implementing a proper maintenance program. This should include regular inspections of the roof’s safety, condition, and functionality.


The last cause of green roof fires is arson. This includes the deliberate setting of a fire on your building’s property for any reason, whether it be personal or political.

arson attack

Arson can have devastating effects because all those flammable materials are sure to burn quickly and intensely. Plus, this type of attack can easily spread to other parts of the building.

Therefore, it’s important to have a comprehensive security plan in place that includes measures to prevent arson. This can include installing cameras and other surveillance equipment, having a well-trained security staff, and using fire-resistant materials on the roof.

How to prevent fires on green roofs?

There are many great ways to prevent fires on green roofs. Building projects can avoid many of the causes that lead to wildfires by implementing a combination of the following strategies.

Control smoking materials and open flames

Smoking materials and open flames should never be brought onto a green roof. This includes smoking cigarettes, cigars, or pipes.

Lighting candles or any kind of open flame should also be avoided because the materials found in green roofs are extremely flammable and can catch fire quickly.

Design the roof for safety

Strive for simplicity when designing a green roof. Keep mechanical equipment, solar panel, or other energy systems away from the edge of the roof.

This ensures that there is enough room for firefighters to access and work around these potentially hazardous systems if a fire does arise.

Build for longevity, not cost reduction

When it comes to green roofs, you get what you pay for so don’t skimp on quality. Choose materials and designs that will last for the lifetime of the building. This may cost more initially, but it’s a much wiser investment in the long run.

Install a fire-resistant barrier

Fire-resistant barriers are a great way to protect the sections of the building by the green roof. They can help keep the fire from spreading throughout the structure and give you more time to put out the flames before they spread too far.

These can include stone, metal, or ceramic materials that will help slow down the spread of flames.

Walls, floors, and ceilings can be planned and built to prevent the passage of fire and smoke.

For example, a one-hour fire resistance wall is constructed as a barrier to withstand the passage of a normal fire for one hour. These barriers are organized to create compartmentation: they split the building into sections to minimize the size and spread of a normal fire.

Use non-combustible materials on the roof’s surface

Combustible roofing materials, such as wood shingles, plastic, and rubber, should be avoided on green roofs. Instead, use materials that are non-combustible, such as metal, concrete, or brick for the roof’s surface. This will help to prevent any kind of fire from spreading.

Use fire-retardant materials in your design

Fire-retardant materials will help to slow the spread of fire on the roof. This will give you more time to get people out and put the fire out. This doesn’t only include green roofing materials, but also the roof’s surface, furnishings, and decorations.

There are many different materials that have been treated with a fire retardant. Choose the material that is best suited for your project and make sure to use it throughout the design.

A roof covering’s fire rating is typically either Class A, Class B, Class C, or unrated.

Unrated roofs are the most vulnerable. The most frequent unrated roof covering is one made of non-fire retardant treated wood shakes or shingles. Those who live in wildfire-prone areas should opt for Class A.

Asphalt fiberglass composite shingles and concrete or clay tiles are common Class A roof coverings. Some materials have a Class A fire rating “by assembly,” which means that extra materials must be employed between the roof covering and the roof sheathing to achieve the fire rating.

Aluminum, some fire-retardant wood shake products, and recycled plastic are examples of roof coverings with a “by assembly” fire rating. If you have a wood shake roof and don’t have or can’t find the manufacturer’s documentation, presume it’s unrated.

If you live in a wildfire-prone location and your roof is unrated or needs to be replaced, IBHS recommends installing a Class A fire-rated roof.

Replace your roof covering (If needed)

Your roof should be replaced if it cannot be improved with repairs. This should be done by professional roofers who have the experience and knowledge to do the job correctly.

If your roof is made of untreated wood shakes, the only way to reduce your wildfire danger is to replace it with a rated roof covering. IBHS recommends installing a Class A covering if you live in a wildfire-prone location.

Roof fire ratings indicate how well they protect against fire. Class A offers the best protection, while Class C offers the least.

Unrated roofs, like untreated wood shake roofs, should be replaced with rated roofs. Class A roofs are widely available and reasonably priced. Regardless of roof type, it should be kept clean and free of debris. You can contact your local building and fire departments for more information about roof ratings and local requirements.

Roofing materials can be Class A rated based only on the covering (a stand-alone Class A covering) or on the covering plus an underlying material used to improve fire performance (Class A by assembly).

The American Society for Testing and Materials (ASTM) Standard Test Method E-108 is used to assess the fire rating for roof coverings. This test assesses flame spread across the roof covering, the ease with which fire can infiltrate through the roof (and into the attic or ceiling area), and the roof covering’s ember generating capacity.

If the flame propagation is excessive, or if fire penetrates the roof covering and underlying structural elements, the covering cannot be classified as Class A.

Make sure all installation instructions are followed and that all supplies are used when utilizing an assembly-rated Class A covering. If installation procedures are altered or non-standard materials are used, the assembly may lose its Class A fire rating.

Many non-combustible roofing materials earn a stand-alone Class A classification by meeting the building code’s noncombustible standard. As a result, they do not need to be tested to the ASTM E-108 standard and rated for fire resistance (e.g., a Class A, Class B, or Class C fire-resistant rating).

An aluminum coating is an exception to this general norm. It must be evaluated due to its low melting point. In order to receive the Class A (by assembly) grade, installation instructions will entail the usage of an extra material beneath the aluminum coating.

Wood shakes treated with a fire-retardant chemical can achieve a Class A assembly rating. However, wood shakes treated with fire retardants are not permitted in every state.

Install sprinkler systems on your roof

Sprinkler systems are firefighting systems that are activated in the event of a fire. They typically consist of a network of piping that runs throughout the building and is connected to a water supply.

When a fire is detected, the system activates by releasing water through the piping to extinguish the fire.

Sprinkler systems are successfully utilized in many different projects including commercial buildings and large-scale industrial plants. They can also be applied to green roofs.

If you have a commercial building you most likely have sprinkler systems installed. If the existing sprinkler system doesn’t serve your green roof, you can consider adding a new sprinkler system to your building.

This can be achieved by extending the piping to the roof or by installing a new system specifically for the green roof. Having a sprinkler system, you have to make sure fire pump rooms/riser rooms are completely devoid of all non-firefighting equipment.

Provide fire extinguishers at regular intervals

In the event of a fire, it is important to have access to a fire extinguisher. Make sure you place fire extinguishers in an accessible place. It is also important to label the extinguishers so that employees know how to use them properly and what types of fires they can combat.

Make sure all fire extinguishers are fully charged, in good condition, easily accessible and none are missing at any time.

Also, make sure your employees are trained and know how to use the fire extinguishers properly in case of an emergency. Every once in a while you can hold regular training sessions to refresh their memory.

Install a comprehensive security system

A good security system will help to deter crime, including arson, on your property. It’s important to have a plan in place to keep the building and people around it safe.

Having a security system in place can protect your green roof from potential vandals and firebugs. Having an efficient alarm system is crucial to keeping the building safe at all times but also for protecting each individual component of the green roof (e.g., plants).

Install barriers, such as fences or signage that discourage trespassers. Make sure your security system is up-to-date and functioning properly.

Regularly test the alarm systems and keep all cameras in good working condition. Having a well-functioning security system can help to minimize crime on your property, including arson.

Keep chimneys clean

Chimneys can become blocked with debris. These blockages are the leading cause of chimney fires in most cases. Make sure all your fireplaces and wood stoves are cleaned on a regular basis to keep them running safely.

Keep your plants healthy

Some plants are more resistant to fires than others. Check with your local code department before designing a roof that has vegetation on it. They may have suggestions as to what types of plant life would be best for the area where you plan on building.

Healthy plant life is much more resistant to fires than dead plants. Make sure you have regular watering and fertilizing schedules in place to keep your plants healthy and looking great.

Regularly remove trash/waste

Trash/waste can easily start a fire if it’s not disposed of properly. Make sure you have a regular schedule for removing trash and waste from the building.

If there is an accumulation of combustible materials, it can provide fuel for a potential fire. Keep your property clean and free of any unnecessary flammable material to help prevent fires.

Provide fire-safety education

Fire safety requires knowledge of fire and its effects. Also, it is important for everyone in your building for fighting fires. Therefore, train your staff and occupants in fire safety.

Delegate roles and responsibilities to the people who work in your building. Make sure you have an action plan to follow during a fire emergency so everyone knows what they are expected to do.

Having knowledgeable occupants onsite is crucial for preventing and fighting fires effectively. Provide regular training sessions so that all of your employees know how to use equipment properly, keep their cool during emergencies, and work together as a team.

Mark the emergency exits

Every building should have clearly marked emergency exit paths. Make sure your green roofs are included in this by marking the different routes of escape.

Fire exit routes should be clearly marked and easily accessible. Fire doors should also be kept unlocked during business hours. In the event of a fire, it’s important that everyone knows how to get out safely. Make sure to test your emergency exit plan regularly.

As crucial as unblocked exits are for fire safety, individuals discovering escapes is a critical safety element in your structures. Exit signage and illumination must be continuously illuminated and plainly visible, even during a power loss, according to NFPA 101.

Exit signs must be bright and free of obstructions, emergency lighting units must be operational, and exit sign and lighting backup batteries must be completely charged and reliable.

Fire alarm systems and evacuating the premises during a fire or other emergency go hand in hand.

Building fire prevention systems include the fire alarms themselves, as well as all components that make them work, as well as those that feed into the alarms and are connected to them (fire sprinklers, smoke detectors, heat detectors, evacuation systems, etc.).

They detect and alert people to a variety of life-threatening and property-damaging threats other than fire, including carbon monoxide poisoning and faulty pipes, as well as severe weather and active shooters (NFPA 3000), thus it is vital that they work 100% of the time.

Work with a full-service fire protection company

When it comes to fire protection, it’s always best to consult with a professional. They can help you design and implement a plan that will keep your green roofs safe.

Look for a fire protection company that has experience with the specific type of building you have. Make sure they are up to date on all the latest fire safety codes and regulations.

A full-service fire protection company can help you with all your fire safety needs, from designing a plan to installing the necessary equipment. They will stay up to date on all the latest fire codes and regulations, so you can rest assured your building is safe.

Review your insurance policy

It’s important to review your insurance policy and be sure that you are fully covered in case of a fire. Make sure to update your policy if you make any changes to your building, including the installation of a green roof.

Clean roof drains and gutters regularly

Wind-blown debris, such as leaves and pine needles from surrounding and overhanging trees, will build upon roofs and in gutters.

Wind-blown embers can ignite dry material. These flames can spread to the roof’s edge and surrounding siding. Even with Class A fire-rated roof coverings, the ignited debris will expose vertical surfaces near the roof edge to flames. Therefore, remove vegetative debris from your roof and gutters on a regular basis.


A green roof is a great addition to any building. They provide insulation, a natural habitat for animals and plants, and require less maintenance than traditional roofs. However, they are not fireproof or resistant by default.

In order to keep your green roof safe from potential fires, make sure to take the necessary precautions, such as installing emergency exits, marking escape routes, and having a reliable fire alarm system.

Work with a full-service fire protection company to design the best plan for your building. Review your insurance policy to make sure you are covered, and finally stay aligned with fire safety regulations in your area.