Best Torch Down Roofing Materials

Torch Down Roofing is a popular low-slope roofing solution for many U.S. commercial and residential buildings. This article explains the key materials, compares their performance, cost, and installation considerations to help determine the best torch down roofing material for a given project.

Material	Reinforcement	Durability	Typical Use
Rubberized Asphalt (SBS)	Fiberglass Or Polyester Mat	High (15–25 Years)	Residential/Commercial
Atactic Polypropylene Modified (APP)	Fiberglass Mat	Moderate To High (10–20 Years)	Hot, Sunny Climates
Granule-Surfaced Torch Sheets	Mineral Granules	High (Improved UV Protection)	High-Exposure Roofs

What Is Torch Down Roofing

Torch down roofing is a method where heat is applied to roll roofing sheets to fuse them into a seamless membrane. It typically uses modified bitumen sheets, such as SBS (Styrene-Butadiene-Styrene) or APP (Atactic Polypropylene), which are reinforced with fiberglass or polyester for strength and dimensional stability.

Common Torch Down Roofing Materials

SBS Modified Bitumen

SBS is a rubberized asphalt compound that adds elasticity and flexibility to the membrane. SBS performs well in cold climates because it remains flexible in low temperatures and resists thermal cracking better than non-rubberized alternatives.

APP Modified Bitumen

APP modification makes asphalt more plastic-like and improves heat resistance. APP is often chosen for hot, sunny regions because it tolerates higher surface temperatures and can be surfaced with reflective coatings or granules for UV protection.

Fiberglass Or Polyester Reinforcements

Reinforcements add tensile strength and puncture resistance. Fiberglass provides dimensional stability and fire resistance, while polyester adds tear strength and flexibility for roofs with movement or irregular substrates.

Granule-Surfaced Sheets

Mineral granules embedded on the surface offer UV protection and abrasion resistance. Granule-surfaced torch down sheets extend service life and are common on roofs with prolonged sun exposure or foot traffic.

Performance Comparison

Property	SBS	APP
Flexibility At Low Temp	Excellent	Good
Heat Resistance	Good	Excellent
UV Resistance	Improved With Granules	Improved With Granules/Coatings
Puncture Resistance	High (With Reinforcement)	High (With Reinforcement)

Installation Process And Best Practices

Torch down installation involves heating the underside of the roll to melt the asphalt and bond it to the substrate. Proper surface preparation, correct torch technique, and seam overlap are critical to achieve a watertight membrane and avoid hazards like blistering or insufficient adhesion.

Surface Preparation

The deck must be clean, dry, and structurally sound. Installers often apply a base sheet or primer to promote adhesion and create a uniform substrate for the torch-applied membrane.

Seaming And Terminations

Seams are heat-welded and pressed to ensure continuity. Flashing and drip edges require careful sealing and metal terminations to prevent water intrusion at roof perimeters, penetrations, and transitions.

Safety Considerations

Torch work carries fire risks, so trained installers use heat shields, fire watches, and fire-resistant clothing. Local codes may require fire certs or alternative cold-applied systems in some areas.

Durability, Lifespan, And Maintenance

Torch down roofs typically last between 10 and 25 years depending on material selection, installation quality, and climate. SBS with granules and proper maintenance often delivers the longest service life, especially in temperate or cold climates.

Routine Maintenance

Regular inspections and prompt repairs of blisters, splits, or damaged flashing reduce water infiltration risks. Annual inspections and clearing debris extend membrane lifespan and help identify issues early.

Common Failure Modes

Failures often stem from poor installation, ponding water, UV degradation, or mechanical damage. Addressing drainage, protecting exposed seams, and using reflective coatings mitigates these problems.

Cost Considerations

Material and labor costs vary with region, roof complexity, and material type. SBS systems typically cost more than standard roll roofing but provide better performance and longevity, while APP may be priced competitively in hot-climate markets.

Item	Typical Cost Range (Per Square)
APP Torch Down Installation	$200–$350
SBS Torch Down Installation	$250–$450
Repairs / Flashing Work	$100–$600

Environmental And Energy Considerations

Reflective coatings or light-colored granules reduce heat absorption and cooling loads. Choosing a reflective surfacing or a cool-roof coating can lower energy costs and improve roof longevity in warm climates.

When To Choose Each Material

Project requirements and climate drive the material choice. SBS Is Best For Cold Or Variable Climates Needing Flexibility; APP Is Best Where Heat Resistance And UV Tolerance Are Priorities.

Examples

• Cold Northern Home: SBS With Polyester Or Fiberglass Reinforcement For Flexibility.
• Southern Commercial Building: APP With Granules Or Reflective Coating For Heat Resistance.
• High-Traffic Roof: Granule-Surfaced SBS Or APP With Reinforced Ply For Abrasion Resistance.

Choosing The Best Torch Down Roofing Material

Select based on climate, roof slope and exposure, budget, and desired lifespan. Prioritize reputable manufacturers, certified installers, and systems with proven track records to maximize performance.

Checklist For Selection

1. Confirm Local Climate Challenges (Heat, Cold, UV).
2. Evaluate Roof Deck Condition And Slope.
3. Decide On Reinforcement Type (Fiberglass Vs Polyester).
4. Consider Surface Options (Granules Or Smooth With Coating).
5. Get Multiple Quotes From Experienced, Insured Installers.

Key Takeaways

The best torch down roofing material depends on climate and performance priorities: choose SBS-modified systems for flexibility in cold climates, APP for heat resistance, and granule surfacing or reflective coatings for UV protection and extended service life. Professional installation and routine maintenance are essential to achieving the expected lifespan.