Yes. Tar paper is generally combustible, so it can catch fire when exposed to an ignition source and may contribute fuel to a fire. The exact risk depends on the product, its condition, and how it is installed. The term “tar paper” is also used loosely for several roofing felts, most of which are saturated with asphalt rather than coal tar. Knowing what the material is—and what its fire rating does and does not mean—helps homeowners and contractors handle it more safely.
What Is Tar Paper?
Tar paper is a common name for asphalt-saturated felt used in roofing and, in some applications, construction. Traditional felt products have a fibrous base, often made from organic material or fiberglass, that is saturated or coated with asphalt. The asphalt helps resist water, while the base provides the sheet’s structure. Roofing felt is installed beneath shingles or other roof coverings as an underlayment.
Although the name suggests coal tar, many products sold or described as “tar paper” contain asphalt. Asphalt and coal tar are different materials, and a product’s exact composition should be checked on its label, technical data sheet, or safety data sheet (SDS). Modern synthetic roof underlayments, meanwhile, may be made from woven or nonwoven polymers and are not necessarily tar paper.
Products vary in thickness, backing, surface treatment, and intended use. Those differences can affect how a sheet burns, but they do not make an unfamiliar product safe to expose to a flame. For fire-safety decisions, use the documentation for the specific product rather than relying on the generic name “tar paper.”
Is Tar Paper Flammable or Combustible?
In ordinary construction use, asphalt roofing felt is considered a combustible material. It can ignite if exposed to sufficient heat or flame, and a fire can spread across or through it depending on the surrounding materials and conditions. “Combustible” describes a material that can burn; it does not mean that the material will ignite instantly at room temperature or that every product behaves identically.
It is not useful to give one universal ignition temperature for tar paper. The result can vary with the product’s composition, thickness, moisture, airflow, exposure time, and test method. In addition, a temperature reported for asphalt alone does not necessarily predict the ignition behavior of a finished felt sheet installed on a roof. The manufacturer’s SDS and technical literature are the appropriate sources for product-specific information.
Tar paper can also release smoke and irritating or hazardous combustion products when it burns. The composition of the smoke depends on the materials involved and the conditions of the fire. Burning roofing felt should never be used as a disposal method, and smoke should not be inhaled. If a roof or construction material is burning, people should leave the area and contact emergency services.
Why Roofing Felt’s Fire Rating Can Be Misleading
A fire classification associated with a roof usually applies to a tested roof assembly, not to a loose sheet of underlayment by itself. The assembly may include the roof covering, underlayment, roof deck, insulation, and other components installed in specified ways. A classification such as Class A, B, or C describes the tested assembly’s performance under the relevant test standard; it does not mean that every component is noncombustible or fireproof.
For example, a roof covering may be part of a Class A-rated assembly while the underlayment beneath it remains combustible. The rating is valid only when the components and installation match the tested or approved system. Substituting a different underlayment, changing the roof deck, or altering installation details can affect whether the assembly qualifies for that rating.
Fire ratings can also refer to different kinds of performance. A roof-covering classification is not the same as a material’s reaction to a direct torch flame, a fire-resistance rating for a wall or floor, or a statement that a material cannot burn. Product labels and building documents should be read in context, and local code requirements should be checked with the building department or a qualified roofing professional.
Common Situations That Increase Fire Risk
Tar paper is most concerning when it is exposed, stored near an ignition source, or used around work that produces sparks or high heat. Once installed beneath shingles or another approved roof covering, it is less exposed to direct ignition, but it should not be treated as fireproof. Construction sites can present several hazards at once, including hot work, temporary electrical equipment, fuel, dry debris, and strong airflow.
- Open flames and torches: A torch can ignite felt, nearby wood, dust, or other combustible materials. Torch-applied roofing requires trained installers and a system specifically designed for that method.
- Welding, cutting, and grinding: Sparks can travel beyond the immediate work area and land on roofing felt, roof debris, or concealed combustible materials.
- Smoking and discarded matches: A cigarette or match can start a fire when it contacts exposed combustible material, especially where debris has accumulated.
- Temporary heaters and lamps: Poorly positioned heaters or work lights can overheat nearby materials. Required clearances and product instructions should be followed.
- Electrical faults: Damaged cords, overloaded circuits, and temporary wiring can create an ignition source around stored or installed materials.
- Storage and disposal: Rolls stored beside hot equipment, or scraps placed near an active work area, add avoidable fuel to a fire.
Concealed spaces deserve attention as well. A small ignition on a roof can potentially involve the deck, framing, insulation, or other materials. A fire may travel through hidden cavities before it is visible from inside the building. That is one reason post-work checks and adherence to hot-work procedures matter.
How to Reduce Fire Risk During Roofing Work
Safe handling starts with identifying the product and following its installation instructions. The manufacturer’s documents may specify suitable applications, storage conditions, compatible roof systems, and restrictions on exposure to heat. If the product is old, unmarked, or damaged, a roofing professional can help determine what it is before work begins.
- Keep rolls and scraps away from ignition sources. Store them in a designated area, away from torches, heaters, smoking, and hot equipment. Keep work areas orderly and remove scraps routinely.
- Plan hot work before it starts. Welding, cutting, grinding, or torch work should follow the applicable site safety procedures. Identify combustible materials, protect or remove them where practical, and use appropriate fire protection.
- Use trained installers and approved methods. Roofing systems that involve open flame require specific experience and compatible materials. A product intended for one application should not be assumed suitable for torch application.
- Control sparks and heat. Use suitable barriers or shielding where required, maintain safe clearances, and keep appropriate fire-extinguishing equipment accessible. Fire protection should be selected and used by trained personnel.
- Inspect the area after work. Follow the site’s hot-work fire-watch procedures, including any required monitoring period. Check the work area and nearby concealed spaces when the procedure calls for it.
- Follow local rules. Building codes, fire codes, permits, and jobsite requirements can vary by location and project. Confirm requirements with the local authority having jurisdiction.
OSHA’s construction rules include precautions for welding, cutting, and heating, such as controlling fire hazards and providing suitable fire protection. OSHA requirements apply to covered workplaces; they are not a substitute for a project-specific safety plan or local fire-code rules. The OSHA standards and the jobsite’s written procedures should be consulted for the work being performed.
Does Tar Paper Make a Roof More Likely to Catch Fire?
The presence of roofing felt alone does not determine a roof’s overall fire risk. A roof’s performance depends on the complete assembly, the type and condition of the covering, the deck and other layers, installation quality, nearby hazards, and exposure to embers or flame. Underlayment is normally covered by the roof covering, but construction, repairs, damage, or incomplete installation can leave it exposed.
In areas prone to wildfires, roof-covering selection and installation are especially important. Embers can collect in roof valleys, gutters, and other places where dry leaves or debris accumulate. A compliant roof assembly and routine removal of combustible debris can reduce vulnerabilities, but no single layer makes a building fireproof. Homeowners should follow local wildfire guidance and consult a roofing professional about approved materials and assembly details.
If tar paper is temporarily exposed during a repair, keep flames and hot work away from it and protect the area as required by the work plan. If the felt is damaged, charred, or has been exposed to a fire, a qualified professional should assess the affected roof system. Surface appearance alone may not reveal damage to the underlayment, deck, or concealed components.
Tar Paper Compared With Other Roofing Underlayments
Asphalt-saturated felt is only one type of roofing underlayment. Synthetic sheets and other products may differ in weight, durability, installation requirements, and fire behavior. A label such as “synthetic” does not automatically mean noncombustible, fireproof, or suitable for every roof system. The product’s specifications and approved uses should be checked before making a comparison.
| Material | Typical description | Fire-safety consideration |
|---|---|---|
| Asphalt-saturated felt (“tar paper”) | Fibrous sheet saturated or coated with asphalt; commonly used beneath roof coverings | Generally combustible; keep away from flames and follow the tested roof assembly requirements |
| Synthetic underlayment | Often made from polymer-based sheet materials | Fire behavior varies by product; check the SDS, technical data, and roof-system approval |
| Fire-rated roof assembly | A combination of specified roofing and structural components tested as a system | Rating applies to the tested configuration, not automatically to each individual layer |
These descriptions are general, not product certifications. A roofing material should be selected for the roof design, climate, code requirements, and manufacturer’s instructions—not solely by assumptions about whether one category is “safer” than another.
What to Do if Tar Paper Catches Fire
If roofing felt catches fire, people should move away from the danger and alert others. For a fire that is spreading, involves a roof or structure, or cannot be controlled safely, call 911 and follow the emergency dispatcher’s instructions. People should not climb onto a burning roof or attempt to fight a fire without the training, equipment, and a safe escape route required for that response.
After a fire, the affected roof should be inspected by qualified professionals before repairs or re-occupancy decisions are made. Fire, heat, and water used in suppression can damage components that are not visibly burned. Documentation from the roof-system manufacturer, the installer, and the responding fire department may help guide evaluation and repair.
How to Verify a Product’s Fire Information
For a specific roll or installed roof, begin with the manufacturer’s name and exact product designation. Look for the product data sheet, SDS, installation instructions, and any evaluation report or approval that applies to the intended roof assembly. These documents can clarify composition, use limitations, and applicable test information.
For a building project, confirm that the complete roof assembly matches the approved design and local code. A contractor, architect, building official, or fire-safety professional can help interpret documents when the assembly has been altered or the rating is unclear. The International Residential Code and International Building Code provide model requirements, but the code edition adopted by a particular jurisdiction—and any local amendments—controls.
Useful sources include the OSHA construction standard on fire prevention during welding and cutting, the International Code Council’s model codes, and product-specific manufacturer documentation. These references address different questions: workplace hot-work precautions, building-code provisions, and the properties or approved uses of a particular product.
Key Takeaway
Tar paper is generally combustible, but its precise fire behavior depends on the product and the conditions. A roof’s fire classification usually describes a tested assembly rather than proving that its underlayment cannot burn. Keeping felt away from sparks and flames, following product instructions and hot-work procedures, and verifying the complete roof system are practical ways to manage the risk.