The Ultimate Guide to Commercial Roofing

A roof being built in Utah Choosing the right roofing materials for commercial buildings is a critical decision that impacts not only the immediate aesthetic appeal and functionality of the structure but also its long-term viability and cost-effectiveness. The roof of a commercial building plays a crucial role in protecting the interior from the elements, contributing to energy efficiency, and defining the overall architectural character of the building. Therefore, selecting the most appropriate roofing material requires careful consideration of various factors to ensure that the roof meets the specific needs of the building and its occupants.

Factors for Selecting Commercial Roofing Materials

Several factors influence the choice of roofing materials for commercial buildings. The main considerations for selecting commercial roofing include:

1. Climate and Environmental Considerations

The climate in which a building is located plays a significant role in determining the most suitable roofing material. Materials must be selected based on their ability to withstand the local environmental conditions to ensure the longevity and integrity of the roofing system.

Impact of Climate on Material Choice: Areas with heavy rainfall and high humidity levels require roofing materials with excellent waterproofing and mold resistance, such as single-ply membranes or metal roofing. In contrast, regions that experience extreme heat may benefit from reflective roofing materials that can deflect sunlight and reduce cooling costs.
Importance of Local Weather Patterns: Roofing materials must also be chosen with local weather patterns in mind, including the potential for extreme weather events such as hurricanes, tornadoes, heavy snowfall, or wildfires. For example, buildings in hurricane-prone areas may require impact-resistant materials, while those in areas prone to wildfires may benefit from materials with a high fire resistance rating.

2. Architectural Style and Aesthetics

The architectural style of a commercial building significantly influences the selection of roofing materials, as the roof contributes to the overall aesthetic and character of the structure.

Matching Roofing Materials to Architectural Style: The roofing material should complement and enhance the building’s architectural style, whether it is modern, traditional, or industrial. For instance, metal roofs might suit contemporary commercial buildings with their sleek appearance, while clay tiles could enhance the aesthetic of more traditional designs.
Aesthetic Considerations and Brand Image: The appearance of the roof can impact the brand image of businesses housed within the building. A well-chosen roof contributes to a positive first impression and can reflect a company’s values, such as sustainability or innovation, depending on the material used.

3. Durability and Maintenance

The longevity and maintenance requirements of roofing materials are crucial considerations that affect both the lifecycle cost and the performance of the roof over time.

Comparison of Longevity and Maintenance Needs: Different roofing materials offer varying levels of durability and require different maintenance efforts. Metal roofs may last up to 50 years with minimal maintenance, while asphalt shingles may have a shorter lifespan and require more frequent inspections and repairs.
Cost-Benefit Analysis of Upfront Costs vs. Long-Term Maintenance: While some materials may have higher initial installation costs, their longevity and low maintenance requirements can make them more cost-effective in the long run. This analysis helps in making an informed decision that balances upfront investment against future savings.

4. Energy Efficiency and Sustainability

Where operational costs and environmental impact are increasingly important, the energy efficiency and sustainability of roofing materials are key factors in the selection process.

Importance of Energy-Efficient Roofing: Energy-efficient roofing materials, such as cool roofs, can significantly reduce cooling costs by reflecting sunlight and heat away from the building, thereby lowering indoor temperatures.
Sustainable Roofing Options and Environmental Impact: Sustainable roofing materials, such as green roofs or recycled metal roofs, not only reduce the environmental footprint of a building but can also offer additional benefits such as improved insulation, biodiversity, and stormwater management.

Types of Commercial Roofing Materials

Metal Roofing

Metal roofing is a popular choice for commercial buildings due to its durability and versatility. Common metals used include steel, aluminum, and copper, each offering distinct advantages. Steel roofs are known for their strength and resistance to corrosion, aluminum roofs are lightweight and resist saltwater corrosion, making them ideal for coastal areas, while copper roofing offers exceptional longevity and a distinctive appearance that ages into a green patina over time. Metal roof benefits include:

Longevity: Metal roofs can last up to 50 years or more with proper maintenance.
Durability: They are resistant to cracking, shrinking, and eroding. Metal roofs can also withstand extreme weather conditions, including heavy snow, high winds, and hail.
Energy Efficiency: Metal roofs reflect solar radiant heat, which can reduce cooling costs by 10-25%.

Installation Process Highlights:

The installation of metal roofing typically involves securing the metal panels onto the roof’s framework using clips or fasteners, which allow for thermal expansion and contraction.
Proper installation is crucial to ensure the roof’s watertightness and ability to withstand high winds.

Single-Ply Membranes

Single-ply membranes are a category of roofing materials primarily used in commercial roofing applications due to their durability, flexibility, and ease of installation. These membranes are made from synthetic polymers and come in large sheets that are either fully adhered, mechanically attached, or ballasted to the roof substrate. There are three main types of single-ply roofing membranes, each with its own unique properties and applications:

1. TPO (Thermoplastic Polyolefin)

TPO roofing membranes are made from a blend of polypropylene and ethylene-propylene rubber. They are designed to offer excellent resistance to ultraviolet (UV) light, ozone, and chemical exposure. TPO membranes are particularly valued for their reflective properties, which help reduce cooling costs by reflecting sunlight away from the building. These membranes are typically installed using mechanical fastening or heat welding, which creates a watertight bond at the seams. The benefits of TPO include:

Energy Efficiency: Highly reflective, reducing building cooling costs.
Durability: Resistant to tears, punctures, and mold growth.
Flexibility: Remains flexible in low temperatures, making it suitable for various climates.

2. EPDM (Ethylene Propylene Diene Monomer)

EPDM is a synthetic rubber roofing membrane known for its durability and versatility. It is resistant to weathering, UV radiation, and extreme temperatures, making it an excellent choice for buildings in varying climates. EPDM roofs are black, which can help with heating in cooler climates, though white-coated versions are available for warmer areas to reflect sunlight. Benefits of EPDM include:

Longevity: Can last up to 30 years with proper maintenance.
Low Maintenance: Requires minimal upkeep due to its resistance to weathering and UV damage.
Versatility: Can be installed on flat or low-slope roofs and is suitable for a wide range of buildings.

3. PVC (Polyvinyl Chloride)

PVC roofing membranes are made from a plasticized or rigid form of PVC, which can offer excellent resistance to chemicals, UV light, and fire. These membranes are particularly popular for restaurants and other buildings that may be exposed to oils or chemicals due to their resistance to such substances. PVC is usually white, enhancing its reflective capabilities and making it an energy-efficient option for hot climates. Benefits of PVC include:

Chemical Resistance: Resists a wide range of chemicals, making it suitable for commercial buildings that may have exposure to oils, fats, or solvents.
Fire Resistance: Highly resistant to fire, often achieving a Class A fire rating.
Durability: Features heat-welded seams that create a monolithic, watertight layer over the roof.

Installation Techniques and Considerations:

Single-ply membranes can be installed in various ways, depending on the specific material and the requirements of the building. Common methods include:

Fully Adhered Systems: The membrane is glued to the insulation or roof deck, providing a stable and secure attachment.
Mechanically Attached Systems: The membrane is attached with fasteners to the roof deck, suitable for areas with high wind uplift requirements.
Ballasted Systems: The membrane is loosely laid over the roof deck and held in place by a layer of ballast, such as river rock or pavers.

Built-Up Roofing (BUR)

Built-up roofing (BUR) is one of the oldest and most reliable commercial roofing systems, particularly suited for buildings with low-slope or flat roofs. This type of roofing is often referred to as “tar and gravel” roofing due to its construction from alternating layers of bitumen (asphalt or coal tar) and reinforcing fabrics called roofing felts or ply sheets. These layers are built up on the roof to create a continuous sealed surface, offering robust protection against water and weather.

Components of Built-Up Roofing

Bitumen: Acts as the adhesive and waterproofing agent. Traditionally, bitumen was either asphalt or coal tar, but modern variations may use more advanced materials like atactic polypropylene (APP) or styrene-butadiene-styrene (SBS) to modify the bitumen for enhanced performance.
Reinforcing Fabrics: Also known as ply sheets, these are made from materials like fiberglass or organic mats, providing strength and stability to the roofing system.
Surfacing: The top layer of a BUR system can consist of gravel, slag, mineral granules, or a glass-fiber or mineral-surfaced cap sheet. This layer protects the bitumen and reinforcing fabrics from UV light and physical damage, and in some cases, can provide fire resistance. For energy efficiency, reflective coatings may also be applied.

Benefits of Built-Up Roofing

Durability: BUR systems are known for their longevity, often lasting 20 to 30 years with proper maintenance. The multiple layers provide exceptional resistance to water, making BUR an excellent choice for waterproofing.
Versatility: BUR can be applied to a variety of roof decks, whether they are flat, sloped, or have irregularities.
Thermal Performance: The layers in a BUR system provide significant insulation value, helping to regulate building temperatures and reduce energy costs.
Fire Resistance: With the appropriate top layer, BUR systems can achieve a high fire resistance rating, contributing to the overall safety of the building.

Installation Method Overview

Base Sheet Installation: The process begins with the installation of a base sheet, which is either mechanically fastened or adhered to the roof deck. This layer serves as the foundation for the subsequent layers.
Application of Bitumen: Hot bitumen is then mopped or spread over the base sheet, acting as the adhesive for the roofing system.
Laying of Reinforcing Fabrics: Ply sheets are rolled out into the hot bitumen, embedding them into the adhesive layer. This process is repeated several times, building up the desired number of layers.
Surfacing: Once the desired thickness has been achieved, a final layer of bitumen is applied, and the surfacing material is added. This could be a cap sheet for a smooth finish or loose aggregate for additional durability and UV protection.

The installation of a BUR system requires skilled labor and attention to detail, especially in managing the hot bitumen and ensuring that each layer bonds properly to the last. Despite the labor-intensive installation process, the durability and reliability of BUR systems make them a popular choice for commercial buildings with low-slope roofs.

Modified Bitumen Roofing

Modified bitumen roofing is a modern take on the classic built-up roofing (BUR) system, designed to offer greater flexibility, durability, and ease of installation, especially for buildings with low-slope or flat roofs. This type of roofing material is made by modifying asphalt or bitumen with polymers to improve its performance characteristics. The two most common types of modified bitumen are SBS (styrene-butadiene-styrene) and APP (atactic polypropylene).

Composition and Types

SBS Modified Bitumen: SBS is a type of synthetic rubber that provides enhanced flexibility and elasticity, especially in cold temperatures. This makes SBS modified bitumen particularly suited to areas with fluctuating temperatures, as it can expand and contract without cracking.
APP Modified Bitumen: APP is a type of plastic that increases the aging ability of the roof and enhances its UV resistance. APP modified bitumen is known for its ability to maintain rigidity and resist deformation under high temperatures, making it ideal for warmer climates.

Both types are typically reinforced with fiberglass or polyester fiber matting to add strength and stability. The modified bitumen is then formed into rolls that can be applied to the roof in various ways.

Benefits of Modified Bitumen Roofing

Enhanced Flexibility: The addition of SBS or APP allows the bitumen to remain flexible at lower temperatures and more stable at higher temperatures compared to traditional asphalt.
Durability: Modified bitumen roofs are resistant to tears, punctures, and heavy traffic. They are also waterproof, making them an excellent choice for flat or low-slope roofs where water pooling can be a concern.
Ease of Repair: Damaged sections can be easily cut out and replaced, making repairs straightforward and less costly.
Longevity: With proper installation and maintenance, a modified bitumen roof can last 20 years or more.
Variety of Installation Options: Can be installed using hot-applied, cold-applied, self-adhered, or torch-applied methods, providing flexibility based on the project requirements and local building codes.

Installation Methods

Hot-Applied: Similar to BUR, the bitumen is heated and applied hot. This method requires professional installers with the equipment to handle and apply hot materials safely.
Torch-Applied: The rolls of modified bitumen are rolled out on the roof, and then the underside is heated with a torch as it’s rolled, melting the bitumen to create a bond with the substrate. This method requires specialized skills to avoid fire risks.
Self-Adhered: Some modified bitumen products come with a pre-applied adhesive layer protected by a release film. The installer simply removes the film and rolls the material onto the substrate. This method is safer and cleaner as it avoids the need for open flames or hot bitumen.
Cold-Applied: Cold-applied adhesives can be used to install modified bitumen without the need for heating, making it a safer and more environmentally friendly option.

Modified bitumen roofing combines the proven reliability of traditional bitumen roofing with advancements in material science to provide a flexible, durable, and versatile roofing solution. It’s particularly suited to commercial buildings with low-slope roofs, offering an effective blend of performance, longevity, and ease of maintenance.

Green Roofing

Green roofing, also known as vegetative or eco-roofing, is a sustainable roofing system that incorporates vegetation, soil, and a waterproofing membrane on top of a conventional roof structure. This innovative approach to roofing offers environmental, economic, and aesthetic benefits, making it an increasingly popular choice for commercial, residential, and public buildings in urban areas. Green roofs can be categorized into two main types: intensive and extensive.

Intensive Green Roofs: These are thick, heavy “rooftop gardens” with a wide variety of plants, including shrubs and small trees. Intensive green roofs require a significant amount of soil depth (typically more than 6 inches) to support the diverse plant life. They are more labor-intensive and require regular maintenance such as watering, weeding, and fertilizing. Intensive roofs are often accessible and can provide additional outdoor space for recreation or relaxation.
Extensive Green Roofs: Extensive green roofs are designed to be low-maintenance and are typically not accessible for regular use. They are characterized by a shallow growing medium (usually 2-6 inches deep) and are planted with drought-tolerant succulents, mosses, and grasses that can survive with minimal water and care. Extensive roofs are lighter than intensive roofs and can be installed on a wider range of structures due to their lower weight.

Components of a Green Roof

Waterproofing Layer: This critical component prevents water from entering the building. It is often accompanied by a root barrier to protect the waterproofing from being penetrated by roots.
Drainage Layer: Located above the waterproofing layer, it facilitates the removal of excess water, preventing waterlogging of the plants.
Filter Fabric: This layer prevents soil from clogging the drainage layer while allowing water and air to pass through.
Growing Medium: A specially formulated soil or substrate that is lightweight and designed to retain water while providing support and nutrients to the plants.
Vegetation: The choice of plants depends on the climate, roof type, and desired maintenance level. Plants are selected for their adaptability to the harsh rooftop environment, with a preference for native species.

Benefits of Green Roofing

Environmental Benefits: Green roofs improve air quality, reduce the urban heat island effect, and provide habitats for wildlife. They also manage stormwater by absorbing rainwater, which decreases the burden on city drainage systems.
Energy Efficiency: By providing additional insulation, green roofs can significantly reduce heating and cooling costs, leading to energy savings.
Aesthetic Appeal: Green roofs transform unused urban spaces into attractive and potentially usable green areas, enhancing the aesthetic value of buildings.
Extended Roof Lifespan: The protective layer of vegetation and soil shields the roof from UV radiation and extreme temperature fluctuations, potentially doubling or tripling the lifespan of the roofing membrane.

Installation and Maintenance

The installation of a green roof involves careful planning and consideration of the building’s structural capacity, waterproofing, drainage, and the selection of appropriate plants. Maintenance requirements vary between intensive and extensive systems, with intensive roofs requiring more regular care similar to traditional gardens, while extensive roofs need minimal maintenance, primarily focused on occasional weeding and annual inspections.

Green roofing represents a shift towards more sustainable and eco-friendly building practices, offering significant benefits not only to the building owners but also to the wider community and environment.

Call Skabelund Roofing

Skabelund Roofing are experts on commercial roofing services repair for residents of Logan and Layton, UT. With over 25 years in the roofing business, we can provide your business with consultation, installation, inspection, and repair services. Contact us today to speak with us about your commercial roofing needs.

The Ultimate Guide to Commercial Roofing: Materials, Benefits, and Installation