Commercial Roof Replacement: A Comprehensive Guide

Last updated on March 6, 2024

Commercial roof replacement is an investment every company must consider because it affects the safety, aesthetics, and energy efficiency of your establishment.

Key takeaways:

  • Persistent leaks indicate extensive damage and the need for replacement.
  • Extensive water damage is a critical sign of roof failure.
  • Consider the age of the roof and its expected lifespan.
  • Sagging or blistering roofs may have compromised structural integrity.
  • An unexplained rise in energy bills suggests compromised insulation.

Determining the Need for Commercial Roof Replacement

determining the need for commercial roof replacement

Assessing the current state of your commercial roof is crucial in deciding whether replacement is necessary. Leaks or water damage visible on the interior of your building often indicate roof failure. When the integrity of roofing material diminishes, moisture infiltration can compromise the underlying structure, further validating the need for a new roof.

Routine inspections reveal wear and tear that could escalate into severe problems. Professional evaluations should also note the condition of flashing, as it is essential in preventing water penetration. Sagging or areas of standing water challenge the roof’s structure and may necessitate replacement.

Consider the roof’s age relative to its expected lifespan. Frequent repairs may be more costly in the long term than investing in a new roof. Energy inefficiency is another factor; older roofs may lack current materials that provide better insulation, leading to higher energy costs.

Finally, factor in building codes and energy standards, which might have evolved since the last roof installation. Compliance with these regulations may require a roofing upgrade or complete replacement.

5 Signs You Need Commercial Roof Replacement

5 signs you need commercial roof replacement

Persistent Leaks:
Repeated water intrusion, despite repairs, can signify extensive damage. Persistent leaks often indicate a deteriorated roofing system that patchwork cannot resolve.

Extensive Water Damage:
Visible signs of water damage, including staining, mold growth, or warping of ceiling tiles and walls within the building, are critical indicators that the roof may be failing.

Age of Roof:
Most commercial roofing systems are designed to last between 20 to 25 years. If your roof is approaching or has surpassed its expected service life, it’s time to consider replacement.

Sagging or Blistering:
Sagging sections of the roof or blistering on the roofing material often imply that moisture has compromised the roof’s structural integrity.

Energy Inefficiency:
An unexplained rise in energy bills might suggest that your roof’s insulation is compromised. A well-performing commercial roof plays a significant role in thermal regulation.

Types of Roofing Materials

Flat roofs, favored for their cost efficiency and ease of access, are typically surfaced with EPDM, TPO, or PVC membranes. These synthetic rubbers and thermoplastics offer durability and are known for their resistance to UV radiation and weathering.

Sloped roofs are less common in commercial buildings but can be found in designs that aim for aesthetic appeal or where architectural requirements dictate their use. They can be covered with shingles, tiles, or metal.

Metal roofing, prized for its longevity and sustainability, is often made from coated steel or aluminum and can last for over 50 years with proper maintenance.

Modified Bitumen is an evolution of the old-fashioned built-up roofing (BUR), combining layers of bitumen interspersed with reinforcing fabrics that offer greater flexibility and weather resistance.

The traditional BUR membrane, known as “tar and gravel” roofs, consist of multiple layers of bitumen and reinforcing felts that create a finished membrane, known for its robustness over large flat areas.

When evaluating these materials, consider factors such as the climate of the area, the building’s structural capacity, and the long-term maintenance commitments each roofing type will entail.


Flat roofing systems are a common choice for commercial buildings, primarily for their cost-effectiveness and ease of maintenance. These roofs typically have a slight slope for water drainage and are characterized by their horizontal or nearly horizontal surface.

Key points to consider for flat roofing materials include:

  • Durability: High-quality materials resist weathering, punctures, and foot traffic.
  • Waterproofing: It is vital to prevent water infiltration with robust membrane installation.
  • Insulation: Flat roofs can support a high level of insulation, enhancing energy efficiency.
  • Weight: Ensure the building’s structure can support the weight of the chosen material, including when loaded with snow or water.
  • Ease of Installation: Some flat roofing materials require specialized installation techniques for a watertight seal.
  • Maintenance: Each material will have different maintenance needs; some may require frequent inspections and repairs, while others are more resilient.

Popular materials for flat roofs include TPO, PVC, EPDM rubber, and modified bitumen. Each has unique properties affecting longevity, reflectivity, and installation complexity. When selecting a flat roofing system, consider the building’s specific needs and local climate conditions to optimize performance and lifespan.


Sloped roofing systems are a popular choice for many commercial buildings, particularly those with a more traditional aesthetic. This roofing style facilitates water runoff, reducing the likelihood of standing water and subsequent damage or leaks.

Here are key points to understand:

  • Typical Materials: Asphalt shingles, metal panels, tile, and sometimes wood shakes.
  • Design Variation: From steep to low slope, adaptable to various architectural styles.
  • Drainage Efficiency: Natural inclination allows for superior drainage and debris removal compared to flat roofs.
  • Snow and Ice: Regions with heavy snowfall benefit, as the slope prevents accumulation.
  • Aesthetic Appeal: Offers a classic look and can enhance the building’s visual impact.
  • Installation: Generally quicker than flat roofs due to less extensive infrastructure requirements.
  • Maintenance: Access can be more challenging, yet the slope reduces wear on the roofing material.
  • Lifespan: Dependent on material but generally long-lasting with proper maintenance.

Selecting a sloped roof comes down to aesthetic preference, weather considerations, and budget. Assess these points with a roofing professional to determine suitability for your specific commercial property.


Metal roofs, known for their durability and longevity, can last up to 40 years or more with proper maintenance. They stand up exceptionally well against extreme weather conditions and are fire-resistant, an important safety consideration. Energy efficiency is another key benefit, as metal reflects solar radiant heat, which can reduce cooling costs. Moreover, these roofs are environmentally friendly; made from recyclable materials and are 100% recyclable at the end of their life.

Installation is quick relative to other materials, though it does require skilled labor to ensure proper fit and finish. The initial cost may be higher, but the life-cycle expense often proves economical. Aesthetically, metal roofing offers versatility with a range of styles and colors to complement any architectural design. It’s essential to consider noise levels during rain or hail and the potential for denting, although many modern metal roofs are designed to withstand significant impact.

Modified Bitumen

Modified bitumen is a popular choice for flat or low-slope commercial roofs due to its durability and flexibility. This material is a modern take on the classic built-up roof (BUR) approach, combining layers of bitumen with fabrics that act as reinforcement carriers known as “plies.”

Modified bitumen sheets are factory-fabricated, layered with either a rubber (SBS) or plastic (APP) polymer, and typically installed using one of several techniques: cold adhesives, hot asphalt, or heat welding.

Some key benefits of modified bitumen roofing systems include:

  • Enhanced Longevity: Roofing life is extended due to its high tensile strength, which helps resist tears and punctures.
  • Improved Performance: With polymer modification, the roof can better withstand extreme temperatures and building movement.
  • Versatility: It can be applied in a range of climates and is available in several colors, which can aid in energy efficiency and aesthetic integration.
  • Ease of Maintenance: Due to its uniform composition and installation, locating and addressing leaks or damage is straightforward.
  • Installation Choices: Cold-applied versions reduce the risk of fire hazards during the installation process.

When considering modified bitumen, it’s crucial to account for your building’s structural specifications, as well as the typical weather conditions in your area. These factors will help determine the ideal application method and the specific type of modified bitumen that will deliver the most benefits.

BUR Membrane

Built-Up Roofing (BUR) membranes are one of the oldest and most reliable commercial roofing systems. Composed of alternating layers of bitumen and reinforcing fabrics called roofing felts, BUR offers a finished membrane with multiple waterproofing layers, which is a primary benefit of this system. The number of layers can be varied to help control costs or meet certain durability requirements.

This type of roofing is known for its substantial resistance to water, which is a key consideration in commercial applications. Moreover, its proven track record for longevity spans over a century, making it a go-to choice for many buildings, especially those with flat or low-slope roofs.

The top surface of a BUR system is commonly finished with stone or gravel, which provides an extra layer of protection from sun and weather exposure. It’s a highly customizable solution; the bitumen in BUR can be either ‘hot-applied’ (typically asphalt or coal tar) or applied as a cold adhesive.

Among the chief advantages of BUR are its durability and the redundancy of layers, which, in the event of a puncture, can prevent water from entering the building. Additionally, maintenance and repair of BUR membranes can be more straightforward due to the material’s accessibility and the nature of its installation.

When considering BUR, it’s essential to account for building structure as BUR systems can be heavy, and the roof must support the weight. High thermal performance can be achieved through proper insulation choices, making this system a potential proponent for energy efficiency.

In summary, BUR membranes offer commercial buildings a robust, proven, and customizable roofing solution with the capability to protect against the elements while also contributing to energy conservation efforts. Key points in considering a BUR system include its multi-layer protection, durability, and potential for energy efficiency, though weight and installation method must be weighed in the decision-making process.


Ethylene Propylene Diene Monomer (EPDM) is renowned for its durability and versatility, making it a popular choice for commercial roofing projects. This synthetic rubber offers a long lifespan, typically 20 to 30 years, with proper maintenance. Its resilience against extreme weather, including hail and ultraviolet (UV) radiation, ensures it remains a steadfast protective layer over commercial properties.

One of the primary advantages of EPDM is its ease of installation. Available in large sheets, it can be rolled out to cover vast areas efficiently, reducing seams and potential leak points. This quality also contributes to its water-resistant properties, as fewer seams mean less vulnerability to water infiltration.

EPDM’s dark color absorbs heat, which can aid in melting snow and ice more quickly but may lead to increased cooling costs in warmer climates. However, its insulation properties can be enhanced with the addition of reflective coatings or insulation boards to improve energy efficiency.

Not to be overlooked is EPDM’s environmental sustainability. It is often made with recycled materials and is itself recyclable at the end of its lifespan, reducing its ecological footprint.

When considering EPDM for your commercial roof replacement, factor in your building’s geographic location, climate, and energy performance to ensure it aligns with your specific roofing needs.

Thermoplastic Polyolefin (TPO)

Thermoplastic Polyolefin, commonly referred to as TPO, is a single-ply roofing membrane that offers a blend of durability and cost-effectiveness. This material is favored for its ability to reflect UV rays, helping to reduce cooling costs in commercial buildings. TPO’s flexibility makes it resistant to tears, punctures, and impact damage, which is particularly beneficial in areas subject to extreme weather conditions.

Installation of TPO roofing is typically performed by fastening the material to the roof deck or using an adhesive. Seams between sheets are heat-welded to create a watertight bond, which is a significant advantage over other roofing options where seams may be more vulnerable.

When considering TPO, note that it is available in a variety of thicknesses, generally ranging from 45 to 80 mils. The thicker the membrane, the more durable and longer-lasting the roof will be, though this also affects the material cost.

An eco-friendly aspect of TPO roofing is its recyclable nature at the end of its lifespan, which often extends over 20 years with proper maintenance. The light-colored surface also contributes to its environmental efficiency, as it minimizes heat absorption.

Selecting TPO can be a sound investment for commercial property owners looking for a balance between performance and value. Its ease of maintenance, combined with strong resistance to mold, dirt accumulation, and the potential for punctures, solidifies its position as a smart choice for many commercial roofing projects.


Why are commercial roofs so expensive?

Commercial roofs are expensive due to the higher costs of materials used and the different roofing systems and brands specifically designed for flat roofs.

What is the best roof for commercial building?

The best roof for a commercial building is a metal roof due to its durability, longevity, and low-maintenance nature.

What is the lifespan of a commercial roof?

The lifespan of a commercial roof varies by type, with a flat roofing system lasting an average of 20-25 years, EPDM rubber roofs offering a lifetime of 20-40 years, and TPO roofs functioning effectively for 20-30 years.

What is the most cost effective roof replacement?

The most cost-effective roof replacement typically involves the use of asphalt shingles, although plastic and corrugated metal panels may also be an economical choice if they suit the local climate conditions.

How often should a commercial roof be inspected?

A commercial roof should be inspected at least twice a year, usually in the spring and fall.

What signs indicate an immediate need for commercial roof replacement?

Signs indicating an immediate need for commercial roof replacement include persistent leaks, extensive water damage, significant deterioration of roofing materials, and increased energy bills.

How does the type of business operation impact the choice of commercial roofing material?

The type of business operation directly impacts the choice of commercial roofing material since different businesses, like manufacturing units, restaurants, or data centers, have unique roofing requirements due to factors such as heat generation, ventilation needs, and durability.