Torch down roofing, also known as torch-on roofing, is a reliable system for flat or low-slope roofs that need to withstand the Gulf South’s extreme climate. It uses sheets of modified bitumen, a flexible asphalt material enhanced with rubber or plastic polymers. These sheets are sealed to the roof using a propane torch, creating a watertight, heat-bonded surface that expands and contracts without cracking.
This method forms a seamless, multi-layer membrane that’s ideal for commercial buildings and storm-prone regions, like New Orleans and across the Gulf Coast. Torch down roofs are trusted for their long lifespan, low maintenance needs, and strong resistance to rain, wind, UV rays, and standing water.
Whether you’re protecting a retail building, office, warehouse, or multi-family property, torch down roofing delivers a resilient, energy-efficient solution with proven performance in high-humidity coastal environments. In this guide, we’ll explore the materials used, the system layers, and why this roofing method is one of the smartest choices for Gulf South properties.
Torch Down Roofing in Gulf South Climates
The Gulf South, including New Orleans, Baton Rouge, the North Shore, and the Mississippi Coast, presents extreme roofing challenges. High winds, intense UV radiation, heavy humidity, and seasonal flooding all demand a system that can withstand the elements and last. Torch down modified bitumen roofing is one of the few flat-roof systems proven to perform well in these conditions when installed correctly.
Hurricane-Ready Performance
Fully adhered torch down membranes offer strong wind uplift resistance. Because the material is heat-sealed to the roof deck, it doesn’t lift or peel in gusts, unlike loose-laid or mechanically fastened systems. Many modified bitumen systems meet uplift ratings required by coastal building codes. The multi-layer design also adds redundancy—if one layer is nicked, the others remain watertight.
This makes torch down a strong option for buildings seeking enhanced storm resilience. In areas hit by hurricanes like Ida or Zeta, well-installed mod-bit roofs often held up better than some single-ply systems.
Rain and Flood Resistance
Torch-down roofing repels water during the Gulf South’s intense downpours. Its membrane forms a waterproof barrier, and when installers properly seal the seams, rain can pond temporarily without breaching the roof. Unlike shingle systems that rely on slope and overlap, torch-down roofing creates a continuous surface shield.
In flood-prone areas, builders often install modified bitumen as a secondary waterproofing layer beneath other roofing systems. This design, common in hurricane-resilient construction, helps prevent interior water damage even if the outer surface materials fail.
Heat, Humidity, and Sun Tolerance
Louisiana’s heat and humidity can be punishing for lesser roofing materials, but modified bitumen withstands both conditions. APP-modified membranes perform exceptionally well in direct sunlight and fluctuating temperatures. Granulated cap sheets deflect UV rays, and the asphalt beneath remains stable under high heat.
Crews manage humidity by installing proper vapor barriers and insulation. When they design the roof correctly, moisture escapes through ventilation layers, and the membrane resists softening, blistering, and cracking over time.
Algae and Mold Resistance
Although any exterior surface in the South may eventually show signs of mildew, torch down roofing is relatively resistant. The mineral granules used in cap sheets discourage mold and algae growth. Over the life of the roof, minimal cleaning is usually all that’s needed to keep the surface clear.
Thermal Efficiency and Energy Savings
Cool roof options are available with torch down systems. A white or reflective cap sheet can reduce surface temperatures, improve insulation performance, and help lower indoor cooling costs. This can be especially valuable for buildings in New Orleans and on the Mississippi Gulf Coast, where air conditioning units often operate year-round and are located directly on the roof.
Bottom line: torch down roofing offers a rare combination of storm resistance, waterproofing, heat durability, and long-term performance. It’s a strong choice for Gulf South commercial buildings that require a roof to withstand the elements, season after season.
Torch Down Roofing Costs in 2025
Cost is always a key factor when choosing a roofing system. Torch down roofing continues to be a cost-effective solution for commercial flat roofs, offering a strong return on investment when designed and installed correctly. Below is an overview of typical 2025 pricing, cost ranges, and the factors that affect your final quote.
Average Cost Range in 2025
For a standard commercial roof, installing a torch down modified bitumen system typically costs between $4 and $9 per square foot for a basic 2 layer setup. A more advanced 3-layer system with added insulation and tear-off could range from $15 to $20 per square foot.
To give context:
- A 1,000 sq. ft. roof may cost between $5,000 and $9,000
- A 2,000 sq. ft. project with full insulation could reach $16,000 or more
Coastal Louisiana and Mississippi may experience slightly higher costs due to local labor rates, hurricane zone compliance requirements, and access conditions in cities like New Orleans.
Factors That Affect Torch Down Roofing Costs
Roof Size and Layout
Larger roofs tend to reduce the cost per square foot; however, the total project cost increases with the surface area. Small jobs under 500 sq. ft. may carry a higher unit cost due to fixed setup expenses. Complex roof shapes with multiple penetrations also increase labor time.
Number of Plies (Layers)
A 2-ply system includes a base and cap sheet. A 3-ply system adds a mid-layer for extra durability and can extend the roof’s lifespan by 5 years or more. Choosing more layers increases upfront cost but improves long-term value.
Insulation and Building Code Requirements
Many commercial projects must comply with modern energy codes, which often require the installation of new insulation. This can add several dollars per square foot, especially when using thick polyiso boards. If your structure already has adequate insulation below the roof deck, you may not need additional layers, which can reduce the total cost.
Tear-Off vs. Overlay
If the existing roof is in poor condition or already has two layers, a complete tear-off is usually required. Tear-off and disposal typically add $1 to $2 per square foot. However, if the current system is sound, a direct overlay may be possible and can reduce both time and expense.
Labor and Site Conditions
Torch-down roofing requires skilled labor due to its open-flame application method. Labor costs comprise a significant portion of your quote. Factors such as downtown access restrictions, fire safety requirements, or occupied buildings may increase labor time and crew size.
Additional Materials
Your quote may also include materials beyond the membrane itself, such as:
- Primers and adhesives
- Flashing and metal edging
- Drain assemblies
- Sealants and cover boards
These elements help complete a professional, durable roof system and are included in any thorough estimate.
Local Considerations in the Gulf South
In the New Orleans and Northshore region, we encourage clients to budget toward the middle or upper end of national price ranges to ensure a long-lasting, code-compliant commercial roof. Cutting corners to reduce upfront cost often leads to more problems, especially in hurricane-prone areas.
Low bids that appear too good to be true often overlook critical components, such as proper insulation, fastening systems, or warranty-grade materials. Reputable contractors spell out every part of the job, including the number of layers, material brands, and workmanship terms..
Long-Term Value and Savings
Torch down systems are built for longevity. While the upfront investment may be slightly higher than some entry-level roof types, the savings add up:
- Fewer repairs over time
- Minimal ongoing maintenance
- Potential energy savings with insulation or reflective cap sheets
This makes torch down a cost-effective option over a 20-year+ lifecycle, particularly when installed correctly the first time.
To get an accurate quote tailored to your building, contact Priority Roofing for a site-specific estimate. We’ll walk through your goals, assess your current roof, and help you choose a system that delivers the best balance of performance and price.
Advantages of Torch Down Roofing
Torch down modified bitumen roofing is a reliable, long-term solution for both commercial and residential flat roofs. Building owners across the Gulf South choose modified bitumen for its proven performance and reliability. Here are the key advantages of choosing torch down roofing:
Waterproof and Resilient
Torch down roofing forms a seamless, watertight barrier. The heat-fused seams lock each layer into place, preventing leaks even on low-slope surfaces. Multiple layers of asphalt-reinforced membrane protect against rain and standing water, critical in regions like Louisiana and the Mississippi Coast. While proper drainage is still necessary, the system itself resists intrusion during heavy storms.
All-Climate Durability
Modified bitumen stays flexible in extreme conditions. It withstands both summer heat and cold snaps, expanding and contracting without cracking. This flexibility makes it a smart option in the Gulf South, where roofs must endure high heat, UV exposure, and occasional winter freezes.
Storm and Wind Resistance
Because torch down membranes are fully adhered to the deck, they are highly wind-resistant. There are no loose edges for gusts to catch. Multi-layer assemblies can also absorb debris impact better than many single-ply systems. For buildings in hurricane-prone areas, this added security can reduce the risk of damage during severe weather.
Long Lifespan
With proper installation and maintenance, torch down roofs often last 15 to 20 years or more. Three-ply systems on commercial properties can last up to 20 years. Their ability to expand and contract with temperature changes helps prevent cracking, and the built-in redundancy of layers enhances durability.
Puncture and Traffic Resistance
Modified bitumen membranes are thicker and more rugged than most single-ply systems. They include reinforcement layers that make them resistant to punctures, tearing, and minor tool drops. This makes torch down a good choice for flat roofs with regular foot traffic, such as those used for HVAC access or light rooftop activities.
Energy Efficiency Options
Though standard torch-down membranes are dark-colored, many manufacturers now offer cool roof cap sheets. These reflective options reduce heat absorption, thereby lowering cooling costs. Pairing a reflective cap sheet with proper insulation under the membrane can enhance interior comfort and reduce HVAC strain, particularly important in the hot, humid Gulf South.
Low Maintenance and Repairable
Torch down roofs require minimal maintenance, and crews can easily handle most repairs. Roofers patch small punctures or open seams by heat-welding another layer of modified bitumen over the damaged area. Asphalt-compatible repair materials, such as roofing mastics, can also be used for temporary fixes. The ability to patch damage without replacing large areas helps keep long-term costs down.
Fire Resistance
Many torch down systems achieve a Class A fire rating when installed over the proper deck or underlayment. The mineral granules on the cap sheet enhance both fire resistance and UV durability. While the installation process uses an open flame, the finished roof offers strong resistance to heat and embers.
Torch down roofing combines durability, weather performance, and long-term value. With the right materials and a knowledgeable local contractor, it offers excellent protection for Gulf Coast properties.
Disadvantages of Torch Down Roofing
Like any roofing system, torch down roofing has a few considerations to weigh. While many of these issues can be addressed through proper installation and planning, it’s essential to understand the potential drawbacks before choosing this system for your property.
Fire Hazard During Installation
Roofers install torch-down roofing with an open-flame propane torch. This method creates strong, fused seams, but also introduces a fire risk if crews don’t follow strict safety procedures. Skilled, insured professionals must handle the work, utilizing proper safeguards such as fire watches and jobsite fire protection.
Some buildings or jurisdictions restrict open-flame roofing methods. In such cases, contractors can utilize alternatives, such as self-adhering membranes. To stay safe and compliant, always hire a licensed roofer trained in torch application and fire safety protocols.
Not a DIY System
Torch down roofing demands professional installation. The tools, techniques, and fire risk make it unsuitable for DIY projects or use by handyman crews. Anyone attempting a torch installation without proper training risks injury and is unlikely to achieve a reliable seal.
While most commercial property owners plan to hire professionals anyway, it’s worth emphasizing: this system requires skilled labor and certified experience.
Odor and Fumes
During installation, heating the modified bitumen may produce asphalt fumes. These are typically less intense than older hot-mop roofing systems, but the smell may still be noticeable during the job. The odor fades once the work is complete. While not a significant issue, building occupants may want to plan accordingly during installation.
More Seams Than Single-Ply Roofs
torch down rolls are typically about 39 inches wide, which means a large roof will have many seams. Each overlap must be carefully heat-welded to avoid leaks. While modern multi-layer systems stagger seams for added protection, the increased quantity of seams relies more heavily on the installer’s skill. A well-installed mod-bit roof rarely has issues, but a poor weld can be a weak point.
Not for Dead-Flat Roofs
Torch down roofing performs best on low-slope roofs. It’s not recommended for completely flat surfaces where water tends to pool. Standing water can degrade the membrane over time, especially in the hot, humid Gulf South. A code-compliant slope (typically 1:12 or greater) and proper drainage solutions—such as tapered insulation or added scuppers—are essential for long-term performance.
Limited Aesthetic Appeal
Modified bitumen roofs are functional, not decorative. While there are some color options in the cap sheet layer (white, grey, tan, black), the overall appearance is industrial. For homes or buildings where the roof is visible from the street, other materials may offer a more visually appealing option. That said, a clean torch down installation can still look professional and well-finished on commercial buildings or multi-family flat roofs.
Upfront Cost vs. Basic Options
Torch down isn’t the most expensive flat roofing system, but it’s not the cheapest either. Due to the multi-layer approach and the requirement for skilled labor, it may be more expensive upfront than thinner, single-layer options. However, its longer lifespan and low maintenance often offset the added investment over time.
Roofers have successfully installed torch down roofing across the Gulf South for decades. Contractors understand its potential drawbacks and address them through thoughtful design and skilled installation. For buildings that demand durability, water resistance, and storm protection, torch-down remains a reliable and proven choice.
What Else Should You Know About Torch Down?
Torch down roofing isn’t just one product—it’s a system composed of several materials, installation methods, and design options. If you’re comparing roofing systems or planning a commercial installation, it’s helpful to understand how torch-down systems are constructed, the materials they comprise, and how they compare to other low-slope options.
In the following sections, we’ll walk through:
- What torch down roofs are made of
- How 2-layer and 3-layer systems differ
- What goes under the membrane
- And how torch down compares to traditional hot-mop roofing
If you’re just here to explore whether torch down is a good fit for your property, please stop here. However, if you’re planning a project or seeking a deeper understanding of modified bitumen roofing, the following sections provide a comprehensive breakdown.
Modified Bitumen Types: APP vs. SBS
All torch down roofing is made from modified bitumen, an asphalt base combined with polymers to enhance performance. The two main polymer types are:
Atactic Polypropylene (APP):
APP membranes are modified with plastic-like polymers, making the material more rigid and highly resistant to heat and UV radiation. APP is well-suited for hot climates, such as those in Louisiana, and is typically applied by torch. Once installed, it forms a rigid surface that resists softening, sun damage, and expansion-related cracking.
Styrene Butadiene Styrene (SBS):
SBS-modified bitumen behaves more like rubber. It’s flexible even in colder conditions and adapts well to building movement. SBS can also be installed with a torch, but is commonly available in peel-and-stick or adhesive-applied formats, making it ideal for buildings where open-flame work isn’t practical.
Both membrane types are widely used and perform well in Gulf South climates. Manufacturers often embed mineral granules into the cap sheet surface to provide UV protection, fire resistance, and a desired appearance.
2-Layer vs. 3-Layer Torch Down Roofs
torch down systems are usually installed in two- or three-ply configurations, depending on the building’s needs and budget.
Two-Layer System:
This setup includes a base sheet and a mineral-surfaced cap sheet. The base layer provides foundational waterproofing. The cap layer, applied on top, adds UV resistance and weather durability. It’s a common choice for standard commercial roofs.
Three-Layer System:
This includes a base sheet, a mid-ply sheet (often smooth), and a cap sheet. The extra mid-layer adds thickness, extends the roof’s service life, and increases impact resistance. Three-ply systems are often chosen for buildings in storm-prone areas or where additional durability is required.
All layers are overlapped and heat-fused, forming a dense, unified membrane. This redundancy provides torch-down roofs with strong protection against seam failure and weather-related stress.
What Goes Into a Torch Down Roofing System
A complete torch-down roof includes multiple layers beyond the membrane itself:
- Insulation:
Typically, rigid polyiso boards improve insulation and may be tapered to create a slope for drainage. - Vapor Barrier:
Prevents interior moisture from entering the roofing system. Essential in humid climates like Louisiana’s. - Cover Board:
A high-density board (e.g., gypsum or fiberboard) installed above insulation to provide a smooth, stable surface for membrane adhesion. It also improves fire resistance and puncture strength. - Base Sheet:
The first layer of modified bitumen is installed directly on the cover board or insulation. Serves as the foundation for the rest of the membrane system. - Cap Sheet:
The top surface is often granulated and available in several colors. It protects against UV rays and weather exposure. In three-layer systems, a mid-ply may be torched between the base and cap layers. - Flashing and Edge Details:
Roofers seal areas around vents, curbs, HVAC units, and perimeters using mod-bit flashing or self-adhered membranes. They prime metal flashing and integrate it with torch-applied materials to create watertight transitions.
Each component plays a crucial role in the roof’s overall performance and must be installed appropriately to prevent issues such as ponding, seam failure, or premature wear.
How Torch Down Compares to Hot-Mopped BUR Roofs
Roofers have long used hot-mopped Built-Up Roofing (BUR) systems on older flat roofs. These systems layer roofing felt and mop hot asphalt between each sheet. While some crews still install BUR today, the process requires more labor and produces strong fumes during application.
Torch down systems offer a cleaner, faster installation using factory-made sheets of modified bitumen. There’s no need to haul hot asphalt to the roof, and the risk of chemical burns or exposure to odors is significantly lower.
Other key differences:
- Torch down roofs are often more flexible and puncture-resistant
- BUR systems may have slightly lower material costs
- Torch down systems generally offer better UV performance and more straightforward repairs.
- Both systems offer multi-layer waterproofing, but torch down is more common in modern applications
For property owners, torch-down typically delivers a longer service life, faster installation, and lower maintenance over time, especially when installed by a certified crew familiar with the Gulf South climate’s demands.
Torch Down Roofing FAQs
Below are answers to common questions about torch down roofing, modified bitumen, and what to expect when considering this system for your flat roof.
Q: What is another name for torch down roofing?
A: Torch down roofing is also called torch-on roofing, and in industry terms, it’s classified as a modified bitumen system. You may also hear it referred to as a mod-bit roof or a rubberized asphalt membrane, all of which refer to the same torch-applied roofing material.
Q: Does torch down roofing work in all climates?
A: Yes. Torch down roofing is flexible and resilient in both hot and cold environments. It resists cracking in winter and softening in summer, making it suitable from the Northeast to the Gulf South. In Louisiana’s intense heat, APP-modified membranes are often preferred for their high heat resistance. In colder areas, SBS-modified membranes offer better flexibility. The key is choosing the right material for the local climate and ensuring expert installation.
Q: How long does a torch down roof last?
A: On average, a well-installed torch down roof lasts 15 to 20 years. A 2-ply system may last up to 15 years, while a 3-ply system can exceed 20 years. Factors such as roof slope, drainage, material type, and regular maintenance all impact the lifespan. In the Gulf South, we’ve seen many torch down roofs remain watertight beyond the 20-year mark with proper care.
Q: How much does it cost to install a torch down roof?
A: Costs typically range from $4 to $10 per square foot for standard 2-layer installations and up to $ 15 or more per square foot for complex 3-layer systems with insulation or tear-off. For a 1,500 sq. ft. roof, this could translate to $6,000–$15,000 or more, depending on project details. Torch down is generally more affordable than high-end flat roof systems and offers substantial long-term value. We recommend obtaining a local estimate to account for Gulf Coast requirements, such as wind uplift compliance.
Q: What materials are used in torch down roofing?
A: Torch down membranes are made from asphalt (bitumen) blended with polymers, reinforced with a fiberglass or polyester mat. The two primary types are:
- APP (Atactic Polypropylene): Plastic-modified, high heat resistance
- SBS (Styrene Butadiene Styrene): Rubber-modified, highly flexible
Most cap sheets have mineral granules embedded for UV protection and color options. Rolls are typically around 3 feet wide and fused with heat during installation.
Q: Is torch down roofing suitable for hurricane-prone areas like the Gulf Coast?
A: Yes. Torch down roofs are well-suited for high-wind zones because the membrane is fully adhered to the roof deck. There are no loose seams to catch wind, and the multi-layer design provides built-in redundancy. With proper edge detailing and installation by regional codes (such as Miami-Dade or FORTIFIED standards), torch-down roofs can perform exceptionally well in hurricane conditions.
Q: Can torch down roofing be installed in winter?
A: Yes. Torch down roofing is frequently installed in cold weather. The torch ensures proper adhesion even when temperatures drop. In the Gulf South, winter installation is rarely a problem. The key is to provide a dry environment and to warm the materials properly. For SBS-modified membranes, cold-weather flexibility is built into the product.
Q: Why are torch down roofing costs online so different
A: Online cost estimates vary widely because many don’t include key factors like insulation, tear-off, local labor rates, or wind-rating requirements. A national average may be helpful for a ballpark range, but the only accurate way to price a torch down roof is through a site-specific quote from a local contractor. At Priority Roofing, our estimates include everything from materials and labor to code compliance, so there are no surprises.
Still have questions about torch down roofing?
Priority Roofing has over a decade of experience installing modified bitumen roofs across the Gulf South. Whether you’re in New Orleans, the Northshore, or along the Mississippi Coast, we can help you find the right roofing solution for your property’s needs and budget.
Contact us today for a complimentary quote or expert consultation. Our team is here to guide you through every step—from material selection to installation and long-term maintenance.