Multi-Ply Asphalt System

Modified Bitumen Roofing

Time-tested modified bitumen roofing systems combining the reliability of built-up roofing with modern polymer technology for superior weather protection and durability.

Multi-Layer
Enhanced protection
15-20 Years
Proven lifespan
Weather Tough
Storm resistant
Easy Repair
Simple maintenance
A roofer torches a membrane layer on a flat roof using a tiger torch to seal the asphalt bitumen, ensuring a durable waterproof layer.
Professional Torch-Applied Installation
Multi-ply waterproofing system

What is Modified Bitumen Roofing?

Modified bitumen is an advanced asphalt roofing system that evolved from traditional built-up roofing (BUR), combining time-tested reliability with modern polymer technology

Two Types of Modified Bitumen

APP (Atactic Polypropylene)

Plastic-based modifier that remains flexible in cold weather. Typically torch-applied, creating a strong bond to the substrate.

  • Best for cold climates
  • Superior cold-weather flexibility
  • Torch or hot-mopped application

SBS (Styrene-Butadiene-Styrene)

Rubber-based modifier providing excellent elasticity and resistance to temperature extremes. Can be torch-applied or cold-adhesive.

  • Superior heat resistance
  • Excellent elongation properties
  • Multiple application methods

Key Benefits

Multi-Ply Protection

Two or more layers create redundant waterproofing for extra security

Extreme Weather Resistance

Withstands high winds, hail impact, and temperature extremes

Easy Repairs

Damaged areas can be patched quickly and economically

Excellent Foot Traffic Tolerance

Durable surface withstands maintenance personnel and rooftop equipment access

Fire Resistant

Class A fire rating available with proper substrate and cap sheet

Perfect for Roofs with Regular Foot Traffic

Modified bitumen's superior durability makes it ideal for roofs that require frequent maintenance access or have rooftop equipment

PROVEN MULTI-PLY SYSTEM

Modified Bitumen Roofing Services

Professional installation, repair, and maintenance of modified bitumen roofing systems throughout Metro Atlanta

Mod Bit Installation

Expert torch-applied and cold-adhesive installation for new roofs and replacements

Torch-Down Repairs

Fast response for leaks, blisters, and membrane damage with permanent torch repairs

Multi-Ply Systems

Base sheet, ply sheet, and cap sheet installation for maximum protection

Maintenance Programs

Preventative care to maximize your modified bitumen roof's 15-20 year lifespan

Benefits of Modified Bitumen Roofing

Modified bitumen combines the proven reliability of traditional built-up roofing with modern polymer technology for superior performance.

Multi-layer redundant waterproofing
Excellent foot traffic tolerance
Superior weather resistance
Easy to repair and maintain
2-3
Layers of Protection
Class A
Fire Rating
50+
Years Proven
Get Free Quote

APP vs. SBS Modified Bitumen

Understanding the two types of polymer modifiers and which is right for your building

APP Modified

Atactic Polypropylene (Plastic-Based)

Key Characteristics:

  • Cold weather flexibility - Remains pliable in freezing temperatures
  • UV resistant - Superior resistance to sun degradation
  • Torch-applied - Heat bonding creates strong adhesion
  • Self-healing - Small punctures can seal in warm weather
Best For:

Cold climates, high UV exposure areas, roofs requiring torch application, and buildings needing quick installation

SBS Modified

Styrene-Butadiene-Styrene (Rubber-Based)

Key Characteristics:

  • Rubber elasticity - Excellent elongation properties for movement
  • Heat resistance - Performs well in hot climates like Georgia
  • Multiple installation options - Torch, cold adhesive, or hot mopped
  • Superior flexibility - Accommodates building movement without cracking
Best For:

Hot climates like Georgia, roofs with lots of movement, cold adhesive applications, and buildings requiring flexible waterproofing

Which Type is Right for Georgia?

In Metro Atlanta's hot, humid climate, SBS modified bitumen is typically the better choice due to superior heat resistance and flexibility. However, APP systems work well for torch-applied applications requiring quick installation.

Choose SBS If:

  • Your building is in Georgia's hot climate
  • You need cold adhesive installation option
  • Maximum flexibility is required

Choose APP If:

  • Quick torch-applied installation is needed
  • Superior UV resistance is priority
  • Self-healing properties are desired

Modified Bitumen Installation Methods

Professional application techniques for maximum performance and longevity

MOST POPULAR

Torch-Applied

Heat bonding with propane torch

  • Strongest bond - Heat fuses membrane to substrate
  • Fast installation - Quick application in good weather
  • Immediate waterproofing - No curing time required
  • Superior adhesion - Best wind uplift resistance

Best For: New construction, roof replacements, and projects requiring quick turnaround

Cold Adhesive

Solvent or water-based adhesive application

  • No open flame - Safe for occupied buildings
  • Weather flexible - Can install in cooler temperatures
  • Quieter application - Less disruptive to tenants
  • Safer for fire-sensitive areas - No ignition risk

Best For: Occupied buildings, fire-sensitive areas, and cold weather installations

Hot Mopped

Hot asphalt application method

  • Traditional method - Proven 100+ year track record
  • Multiple plies - Build up layers for thickness
  • Monolithic membrane - Creates seamless waterproofing
  • Cost-effective - Lower material costs for large areas

Best For: Large commercial roofs, industrial facilities, and budget-conscious projects

Multi-Ply System Configuration

1

Base Sheet

Foundation layer mechanically fastened or adhered to deck

  • Provides first waterproofing layer
  • Smooth or granulated surface
2

Ply Sheet (Optional)

Additional middle layer for extra protection

  • Adds redundancy
  • Increases total thickness
3

Cap Sheet

Weather-resistant top layer with granules

  • UV protection from granules
  • Final waterproofing barrier

Each layer adds protection, with the cap sheet providing the final weather-resistant barrier that protects the underlying layers from UV, rain, and physical damage.

2-ply systems (base + cap) are most common for commercial roofing
Multi-Layer Protection Experts

Get Your Modified Bitumen Roof Quote

Discover if modified bitumen's multi-ply protection, foot traffic durability, and proven 50+ year track record make it the right solution for your commercial building

Torch or Cold Apply

We'll recommend the best installation method for your project

2 or 3-Ply Options

Choose protection level that fits your budget and needs

15-20 Year Warranty

Manufacturer warranties with proven performance history

50+
Years Proven
300+
Mod Bit Installations
24/7
Emergency Service
100%
Satisfaction

Common Modified Bitumen Issues & Solutions

Understanding problems and how we fix them to keep your roof performing for decades

Blistering

Trapped moisture or air between plies creates bubbles that can rupture and leak.

Our Solution: Cut and patch blisters, ensure proper venting, and address moisture sources before repair

Cracking & Splitting

Age, thermal stress, and UV exposure cause membrane to become brittle and crack.

Our Solution: Torch new membrane patches over cracks or apply coating systems to restore flexibility

Seam Failures

Laps between sheets can separate due to poor installation or thermal movement.

Our Solution: Re-torch failed seams, add mechanical fasteners, or install cap strips over problem areas

Punctures & Tears

Foot traffic, falling debris, or equipment installation can puncture the membrane.

Our Solution: Torch-weld patches over damaged areas and install walk pads in high-traffic zones

Ponding Water

Standing water accelerates deterioration and can penetrate through seams and laps.

Our Solution: Improve drainage, install tapered insulation, or apply ponding water-resistant coatings

Granule Loss

Cap sheet granules wash away over time, exposing asphalt to UV damage.

Our Solution: Apply reflective coating system to restore UV protection and extend roof life 10+ years

Modified Bitumen Maintenance Best Practices

Recommended Maintenance Schedule

Bi-Annual Inspections

Spring and fall roof inspections to catch issues early before they become expensive repairs

Regular Cleaning

Remove debris, clean drains, and prevent organic growth that can deteriorate the membrane

Immediate Repairs

Fix small problems immediately before water infiltration causes structural damage

Extending Modified Bitumen Lifespan

Restoration Coatings

At 10-12 years, apply acrylic or silicone coating to restore and protect for another 10+ years

Walk Pad Installation

Protect high-traffic areas around HVAC equipment with walk pads to prevent membrane damage

Drainage Improvements

Address ponding water issues promptly to prevent accelerated deterioration and leaks

With proper maintenance, modified bitumen roofs regularly exceed their 15-20 year expected lifespan, providing excellent return on investment.

Learn About Maintenance Plans