How to Choose the Right Commercial Roofing System in the GTA

For commercial property owners in the Greater Toronto Area, selecting the right roofing system is a critical decision that impacts not only the protection of your building but also your long-term operational costs. With Toronto’s distinctive four-season climate—featuring hot summers, frigid winters, and everything in between—your commercial roof must withstand diverse weather challenges while maintaining energy efficiency and structural integrity.

The GTA offers numerous commercial roofing options, each with specific advantages designed to address different building needs. As a commercial property owner, understanding these options is crucial for making an informed decision that aligns with your budget, building requirements, and long-term maintenance goals.

At Nusite Group, with over 30 years of experience providing waterproofing, roofing, and restoration services throughout the GTA, we’ve helped countless commercial clients navigate this important decision. This comprehensive guide will walk you through the most popular commercial roofing systems available in Toronto, discuss their relative strengths and weaknesses, and provide practical guidance to help you determine which system is right for your specific commercial project.

Built-Up Roof (BUR) Systems: The Time-Tested Solution

What Are BUR Systems?

Built-Up Roof (BUR) systems are one of the oldest and most reliable commercial roofing options, commonly used in North America for over a century. They typically involve applying multiple layers of organic or fiberglass felts (usually four or five plies), each inter-mopped with hot asphalt. The final layer includes a pour of hot asphalt topped with clean pea gravel spread across the roof surface.

Pros of BUR Systems

• Self-healing properties: The multiple layers can provide some natural repair capability • Proven track record: With over 100 years of use in North America, their reliability is well-established • Durability: When properly installed, BUR systems can last 20-30 years • Waterproof performance: The continuous surface without joints or seams provides excellent water resistance • Low maintenance requirements: After installation, these systems need minimal attention • UV protection: They offer excellent ultraviolet protection, reducing roof temperatures and preventing extreme temperature fluctuations inside the building

Cons of BUR Systems

• Environmental concerns: BUR systems produce high odor and pollution from burning hot asphalt • Heat retention: These roofs can contribute to the urban heat island effect as they tend to retain heat • Installation requirements: They need specialized equipment, highly qualified labor, and considerable experience for proper installation • Difficulty identifying leaks: With multiple layers, it can be challenging to locate the source of a leak when problems occur • Shorter lifespan compared to newer options: Despite being less expensive to install, the shorter lifespan may increase long-term costs

When to Choose BUR Systems

BUR systems are ideal for commercial buildings in the GTA that:

Need a proven, traditional roofing solution with decades of reliability
Have a flat or low-slope roof structure
Require a roof that can handle moderate foot traffic
Are in areas where fire resistance is a priority

Modified Bitumen Systems: Flexibility and Strength

What Are Modified Bitumen Systems?

Modified Bitumen systems (sometimes called “rubber roofs”) were introduced to North America as single-ply systems that required a reflective paint coating after installation. They have evolved into two-ply systems that can be applied using hot asphalt, cold applied asphalt, or torch applied methods. The cap sheet typically features a ceramic granular coating embedded in the top surface, similar to what you’d find on shingles.

Pros of Modified Bitumen Systems

• Lighter weight: These systems weigh less than traditional BUR systems • Higher tensile strength: They can better withstand physical stress • Thermal flexibility: They have the ability to expand and contract with a building’s thermal movement • Increased resistance to cold temperatures: Modified Bitumen roofs perform well in Toronto’s winter conditions • Good flow resistance at high temperatures: They maintain integrity during hot summer days • Variety of surface options: Available with factory-applied mineral surfaces, gravel surfaces, or highly reflective “cool surfaces” that reflect sun rays • Color options: Various colors are available to match shingles or other design elements

Cons of Modified Bitumen Systems

• Installation sensitivity: Quality of installation is critical, as proper methodology and techniques are required to heat weld the membranes together • Risk of improper application: Over-torching of materials can lead to premature failure • Seam vulnerabilities: Insufficient bleed out on lap seams is a common cause of premature system failure • Smell during installation: There is often an odor associated with a Modified Bitumen roof during and after installation • Shorter lifespan: Compared to some newer roofing systems, Modified Bitumen typically lasts only 10-20 years

When to Choose Modified Bitumen Systems

Modified Bitumen systems work well for GTA commercial properties that:

Need a lighter roofing solution with good tensile strength
Experience significant seasonal temperature fluctuations
Require a roof that can expand and contract with building movement
Want multiple aesthetic options to match other design elements

Thermoplastic Olefin (TPO) Roofing: The Modern Energy-Efficient Choice

What Is TPO Roofing?

TPO (Thermoplastic Olefin) roofing is increasingly gaining market share in commercial applications. It’s available in various thicknesses, typically 45 mil, 60 mil, and 80 mil configurations. TPO is being embraced by cities like Toronto that are attempting to reduce the Urban Heat Island Effect, as it can help lower the ambient temperature in urban areas, resulting in less energy consumption and a more sustainable environment.

Pros of TPO Roofing

• Easy repair: TPO can be readily fixed when damaged • Fewer seams: Compared to modified bitumen, TPO involves fewer joints where water could penetrate • Lightweight: It puts less stress on the building structure • Safety advantages: TPO requires no open flame application, making it safer for many structures • Environmental benefits: It’s a fully recyclable material that helps combat urban heat island effects • Energy efficiency: TPO roofing can help reduce cooling costs in summer months with its highly reflective surface • Various thickness options: Available from 45 mil to 80+ mil to fit different budgets and durability needs

Cons of TPO Roofing

• Installation expertise: TPO requires specialized installers with technical expertise • Limited installation window: It can only be installed under certain weather conditions – typically between late spring and early fall • Environmental conditions: Installation requires sunshine and no ice, frost, or moisture on the existing roof • Quality variations: The performance of TPO can vary significantly between manufacturers and formulations

When to Choose TPO Roofing

TPO roofing is an excellent choice for GTA commercial properties that:

Want to improve energy efficiency and reduce cooling costs
Are looking for environmentally friendly options
Need a lightweight system that won’t stress the building structure
Are located in areas focusing on reducing urban heat island effects
Have flat or low-slope roof designs

Ethylene Propylene Diene Monomer (EPDM) Roofing: Durable Rubber Option

What Is EPDM Roofing?

EPDM (ethylene propylene diene terpolymer) is a rubber roofing membrane that has become a common choice for low-slope commercial roofing. It possesses excellent weathering, ozone, and ultraviolet resistance characteristics. The membrane can be either fully adhered with bonding adhesive or loose laid and covered with ballast.

Pros of EPDM Roofing

• Clean installation: EPDM offers clean installations without requiring traditional heavy roofing equipment • Efficient installation: With membrane sheets up to 10,000 square feet, EPDM roofs can be installed much faster than conventional built-up or modified bitumen systems • Wind resistance: Available with wind uplift ratings including 1-60, 1-90, and 1-120 • Cost-effectiveness: EPDM is a very cost-effective solution for commercial roofing projects • Durability: When properly installed, an EPDM roof can last more than 20 years • Environmentally friendly: EPDM is considered to have good environmental credentials • Resistance to thermal shock and hail damage: EPDM can accommodate structural movement without damaging the membrane • Recyclability: The material is fully recyclable when it comes time for replacement

Cons of EPDM Roofing

• Aesthetic limitations: EPDM has a utilitarian appearance and doesn’t allow for much personalization • Professional installation requirement: It should not be attempted as a DIY project • Vulnerability to punctures: Despite its durability, EPDM can be punctured during severe storms or by sharp objects • Maintenance needs: Requires regular inspections to identify and address any punctures or issues before they worsen

When to Choose EPDM Roofing

EPDM roofing systems are well-suited for GTA commercial properties that:

Prioritize cost-effectiveness and durability
Have a flat or low-slope roof design
Need excellent resistance to UV radiation and weathering
Can accept the standard black appearance (typically)
Require a roof that can handle Toronto’s freeze-thaw cycles

PVC Roofing: Chemical and Fire Resistant Option

What Is PVC Roofing?

PVC (Polyvinyl Chloride) roofing is another single-ply membrane option available for commercial properties in the GTA. PVC is known as the original heat-welded single-ply roofing system. Although incompatible with asphalt, PVC systems are durable, flexible, and known to resist rooftop chemicals, oils, and industrial byproducts.

Pros of PVC Roofing

• Chemical resistance: PVC roofing can withstand exposure to chemicals, making it ideal for industrial buildings • Fire resistance: These systems have inherent fire-resistant properties • Durability: A PVC roofing system has an average lifespan of 20-30 years with proper installation and maintenance • Energy efficiency: Like TPO, PVC roofing is typically white and reflective, helping to reduce cooling costs

Cons of PVC Roofing

• Higher cost: PVC tends to be more expensive than some other single-ply options • Installation complexity: Requires professional installation with heat-welded seams • Environmental concerns: Some older PVC formulations raised environmental questions • Incompatibility: Cannot be installed over asphalt-based roofing systems without a separation layer

When to Choose PVC Roofing

PVC roofing is particularly suitable for GTA commercial properties that:

House restaurants, manufacturing facilities, or other operations that emit chemicals
Need superior fire resistance
Require a long-lasting, durable roofing solution
Want energy efficiency benefits
Have no existing asphalt-based roofing system (or are willing to install a separation layer)

Metal Roofing: Long-Lasting Premium Option

What Is Metal Roofing?

Metal roofing systems are built to last and, depending on your property type and location, could be the only roofing system your commercial building may ever need. Common materials include steel, aluminum, copper, and zinc.

Pros of Metal Roofing

• Exceptional longevity: Correctly installed and maintained, metal roofing can last as long as the building it covers (70 years or more) • Weather resistance: Metal roofing is highly resistant to rainwater, rot, mold, mildew, and can withstand immense pressure from accumulated snowfall • Warranty advantages: While warranties vary, some companies will cover a metal roof installation for up to 50 years • Fire resistance: Metal roofing materials are noncombustible and resist fire • Environmentally friendly: Most metal roofs contain at least 25 percent recycled materials and are recyclable themselves • Energy efficiency: Metal roofs reflect heat from the sun instead of absorbing it, potentially reducing cooling costs by up to 25 percent in summer • Aesthetic appeal: Many people appreciate the look of metal roofing, which comes in over 100 different colors

Cons of Metal Roofing

• Cost: Perhaps the most significant disadvantage, a metal roofing system can cost between $900-$1,200 per 100 sq. feet, though the durability and longevity justify the investment • Noise concerns: Metal roofs can be noisy during heavy rain • Emergency access difficulties: Metal roofs can be difficult to break through in emergencies • Repair matching challenges: It can be difficult to find exact matches if repairs are needed in the future

When to Choose Metal Roofing

Metal roofing systems are an excellent choice for GTA commercial properties that:

Need a premium, long-lasting solution
Can afford the higher upfront investment
Want maximum fire and weather resistance
Seek energy efficiency and environmental benefits
Would benefit from the distinctive aesthetic appeal

Toronto Climate Considerations for Commercial Roofing

The GTA’s climate presents specific challenges for commercial roofing systems that must be considered during the selection process:

Winter Conditions

Toronto experiences cold winters with average January temperatures between -1°C and -7°C (30°F and 19°F), with occasional colder periods below -10°C (14°F) and sometimes below -20°C (-4°F). The city receives an average winter snowfall of 121.5 cm (47.83 in) downtown.

These conditions require roofing systems that can:

Withstand freeze-thaw cycles without cracking
Support heavy snow loads without structural compromise
Prevent ice dam formation through proper insulation and ventilation
Resist damage from winter maintenance activities like snow removal

For properties in regions with significant snowfall like Toronto, snow retention systems are critical to prevent dangerous snow avalanches from the roof. These systems help retain snow on the roof and allow it to leave gradually in small amounts or as melted water, enhancing safety.

Summer Heat

Toronto summers can be quite warm, and the proximity to Lake Ontario can influence temperatures, with some days experiencing significant temperature differences between areas near the lake and those further inland.

For summer conditions, consider roofing systems that:

Reflect rather than absorb solar heat (like TPO or PVC)
Maintain integrity during temperature fluctuations
Support energy efficiency goals through reflective coatings or materials
Work with the building’s HVAC system to optimize interior comfort

Rain and Storms

Toronto receives an average annual precipitation of 831 mm (32.72 in), with no distinct dry season as precipitation falls regularly throughout the year.

Important roofing features for handling precipitation include:

Excellent waterproofing capabilities
Proper drainage systems to prevent ponding water
Resistance to wind uplift during storms
Durable materials that can withstand hail and debris impact

Spring in Toronto brings milder weather, but heavy rains can still pose a threat by causing or worsening leaks in commercial roofs. Storms with high winds risk lifting or damaging roofing materials. Proper drainage systems and reinforced roofing materials are essential for spring preparedness.

Toronto Building Code Considerations

Commercial buildings in Toronto must comply with the Ontario Building Code (OBC), which sets requirements for structural design and integrity to ensure buildings can safely withstand loads and stresses from environmental factors like snow, wind, and seismic activity.

Toronto also has specific requirements under the Green Roof Bylaw. For industrial buildings greater than 2,000 m² in gross floor area, owners must provide either a green roof covering at least 10% of available roof space (or 2,000 m²) or a roof with cool roofing materials covering 100% of available roof space that complies with stormwater management requirements.

When selecting a commercial roofing system, ensure it meets:

Current OBC requirements for structural loading
Fire resistance ratings appropriate for your building type
Energy efficiency standards
Green roof or cool roof requirements if applicable
Proper permits for installation or replacement

Obtaining the right permit is crucial for commercial roofing projects in Toronto, whether for repairs or complete replacement. Permits help ensure compliance with zoning regulations, building codes, and safety standards. Projects involving structural changes or complete roof replacement typically require permits, while minor repairs may not.

How to Choose the Right System for Your Building

Selecting the ideal commercial roofing system for your GTA property involves considering multiple factors:

1. Building Structure and Design

Roof slope: Some systems work better on flat or low-slope roofs, while others are designed for steeper pitches
Structural capacity: Consider the weight your building can support
Roof accessibility: How easily can the roof be accessed for installation and maintenance?
Existing roofing: Sometimes new systems can be installed over existing roofing, while other times a complete tear-off is necessary

2. Budget Considerations

Initial installation cost: While important, this shouldn’t be the only factor
Long-term maintenance expenses: Some systems cost more upfront but require less maintenance
Expected lifespan: Consider cost per year by dividing the total cost by expected years of service
Energy savings: Reflective roofing may offset costs through reduced cooling expenses

3. Environmental Factors

Energy efficiency goals: Some systems significantly reduce heating and cooling costs
Sustainability priorities: Consider recyclability and environmental impact
Urban heat island effect: Reflective or vegetative roofing helps combat this issue in Toronto
Green building certification: If pursuing LEED or other certifications, certain roofing systems offer more points

4. Maintenance Requirements

Inspection frequency: All commercial roofing requires regular inspection, but frequency varies
Repair complexity: Some systems are easier and less expensive to repair than others
Cleaning needs: Debris removal and membrane cleaning requirements differ by system
Expected service life: Consider how long you plan to own the building versus the roof’s lifespan

5. Specific Building Usage Factors

Rooftop equipment: If your roof houses HVAC units or other equipment, consider access and weight
Chemical exposure: Restaurants or industrial facilities may need chemical-resistant roofing
Foot traffic: Some systems better withstand regular maintenance traffic
Aesthetics: If the roof is visible, appearance may be important

Maintenance Tips for Commercial Roofing in the GTA

Regardless of which roofing system you choose, proper maintenance is essential for maximizing lifespan and performance:

To prolong a roof’s life, maintenance is crucial. As roofs age, problems are inevitable, but addressing maintenance tasks like filling pitch pockets, replacing deteriorated caulking, and fixing blisters and ridges can extend your roof’s lifespan at a reasonable cost.

Seasonal Maintenance Schedule

Spring:

Clear drainage systems of winter debris
Inspect for damage from winter snow and ice
Check for water ponding as snow melts
Examine all flashing and seals

Summer:

Look for blistering or other heat-related damage
Check reflective coatings for deterioration
Ensure HVAC units and equipment are properly secured
Inspect roof access points for security

Fall:

Clear leaves and debris from drains and gutters
Trim overhanging branches that could damage the roof
Prepare for snow loads by reinforcing weak areas
Verify that snow guards or snow retention systems are secure

Winter:

Monitor snow accumulation and remove excessive buildup
Check for ice dam formation
Inspect for leaks during thaws
Keep an eye on areas where ice might damage the membrane

Professional Inspection Recommendations

According to studies, the average life expectancy of a low-slope roof is 13-17 years, but with a Preventative Maintenance Program in place, this average increases to 21 years. To achieve this extended lifespan:

Schedule annual, bi-annual, or quarterly inspections
Include both interior and exterior examinations
Focus on surface damage, water accumulation, and drainage areas
Document and assess findings for planning purposes
Address necessary repairs promptly based on inspection reports

Regular maintenance by commercial roofing professionals will almost always save building owners many thousands of dollars in large, expensive repairs and replacements over the lifetime of the building.

FAQ About Commercial Roofing Systems in the GTA

How long do commercial roofing systems typically last in Toronto’s climate?

The lifespan of a commercial roof varies according to the type and materials used:

EPDM flat roofs can last for around 30 years
PVC roofs can serve you for over 20 years
TPO commercial roofing has a lifespan of around 15 to 20 years

Metal roofing systems can last 20-30 years on average, but up to 45 years or more with consistent maintenance.

The sad reality is that commercial roofs often fail after only 15 or 20 years due to lack of maintenance, when they could and should last 30 years or more.

What are signs that my commercial roof needs replacement?

Key indicators that it’s time to replace your commercial roof include:

Age: If your roof is approaching or has exceeded 20-30 years
Frequent leaks and repairs: Constantly dealing with leaks and requiring frequent repairs
Visible damage: Cracks, blisters, or sagging areas

Additional signs include:

Low spots on your roof where water pools after rain
Flashing damage around protrusions like chimneys and vents
Increased energy bills due to compromised insulation

How much does commercial roof replacement cost in the GTA?

Metal roofs can cost up to $30,000 to install in Toronto, while being a durable and strong option with excellent longevity.

Roof replacement is often a messy and expensive project, with costs typically ranging from $10,000 to $20,000 or even higher for commercial properties.

The exact cost depends on factors including:

Roof size and complexity
Chosen roofing material
Need for removal of existing roofing
Structural repairs required
Rooftop equipment or penetrations

Do I need a permit for commercial roof work in Toronto?

For minor repairs and maintenance, permits may not be necessary. However, for larger projects like complete replacements or structural alterations, permits are typically required.

Structural changes, such as altering the roofline or adding new features, will likely require a permit due to the potential impact on the building’s structural integrity. Commercial flat roof replacement frequently demands permits due to unique structural considerations.

How can I maximize the energy efficiency of my commercial roof?

Energy-efficient roofing options for the GTA include:

Installing reflective membranes like TPO or PVC that reduce heat absorption
Adding adequate insulation to minimize heat transfer
Considering green roof options that provide natural insulation
Ensuring proper ventilation to prevent moisture buildup
Maintaining reflective coatings to preserve their effectiveness

Energy efficiency has become a hot topic in commercial roofing over recent years, with many government roof projects requiring a minimum energy efficiency rating (minimum R-30) on commercial roof systems.

Making Your Final Decision

Choosing the right commercial roofing system for your GTA property requires balancing numerous factors including climate resistance, budget, maintenance requirements, and energy efficiency goals. While initial cost is important, the total lifecycle expense—including maintenance, repairs, energy savings, and replacement timeline—should guide your decision.

At Nusite Group, we understand that every commercial property has unique needs. Our team of experts can provide personalized recommendations based on your specific situation, helping you navigate the complex world of commercial roofing with confidence. With over 30 years of experience serving the Greater Toronto Area, we’ve developed the expertise to match the right roofing system to each client’s requirements.

Whether you’re constructing a new building or replacing an aging roof, investing in a high-quality commercial roofing system tailored to Toronto’s climate will protect your property for decades to come. Contact us today for a consultation to discuss the best commercial roofing options for your property.