Some roofing systems become popular because they’re new.
Others become trusted because they’ve performed reliably for generations.
Built-Up Roofing, commonly known as BUR, belongs to the second category.
For more than a century, BUR systems have protected commercial, industrial, institutional, and government buildings across North America. Although newer membrane systems such as TPO and EPDM have become increasingly common, many existing commercial buildings throughout New Brunswick still rely on built-up roofing because of its durability and proven track record.
If you own, manage, or maintain a commercial building in Fredericton or elsewhere in Atlantic Canada, understanding how a built-up roof works will help you make better decisions about maintenance, repairs, and eventual replacement.
What Is Built-Up Roofing?
Built-Up Roofing is exactly what its name suggests.
Instead of relying on a single waterproof membrane, a BUR system is constructed by layering multiple roofing materials to create a durable, weather-resistant assembly.
A typical built-up roof may include:
- Structural roof deck
- Vapour barrier
- Insulation
- Multiple reinforcing layers
- Bitumen (asphalt or similar waterproofing material)
- Protective surface or aggregate
Each layer contributes to the strength and performance of the complete roofing system.
Rather than depending on one membrane to keep water out, the roof uses multiple layers to create redundancy and long-term durability.
As experienced commercial roofing professionals often explain:
“Commercial roofs perform best when every layer works together. Long-term performance is rarely determined by a single material.”
That philosophy is one reason BUR systems have remained relevant for decades.
Why BUR Has Been Used for So Long
Commercial property owners tend to value predictability.
Built-Up Roofing has earned its reputation because it has consistently demonstrated:
- Long-term durability
- Excellent waterproofing
- Strong resistance to weather
- Reliable performance on low-slope roofs
- Proven service history
Many commercial buildings still have BUR systems because they continue performing well with proper maintenance.
Like every roofing system, however, they require regular inspections and ongoing care.
Built-Up Roofing Performs Well on Low-Slope Roofs
Many commercial buildings have roofs with very little slope.
Unlike residential roofs, which quickly shed water, commercial roofs often retain water for longer periods after rainfall or snowmelt.
Because of this, waterproofing becomes even more important.
BUR systems are well suited to these conditions because their layered construction provides multiple barriers against moisture intrusion.
However, drainage remains essential.
Even the most durable roofing system performs better when water leaves the roof efficiently.
New Brunswick’s Climate Places Additional Demands on BUR Systems
Commercial roofs throughout Atlantic Canada experience challenging weather throughout the year.
These include:
- Heavy snowfall
- Ice storms
- Wind-driven rain
- Freeze thaw cycles
- Summer UV exposure
- Significant seasonal temperature swings
These conditions place continual stress on roofing materials.
As roofing systems expand and contract through changing temperatures, proper installation and regular maintenance become increasingly important.
A well-maintained BUR roof is far more likely to reach its expected service life than one that’s ignored until leaks appear.
The Importance of Drainage
Standing water is one of the greatest challenges facing any low-slope commercial roof.
Poor drainage may contribute to:
- Ponding water
- Accelerated membrane deterioration
- Increased structural loading
- Moisture intrusion
- Freeze thaw damage
Professional inspections evaluate not only the roofing materials but also the roof’s ability to move water efficiently toward drains or scuppers.
In many cases, drainage improvements significantly extend the life of an existing roofing system.
Roof Traffic Matters
Commercial roofs aren’t simply protective coverings.
They’re often workplaces.
Maintenance personnel regularly access rooftops to service:
- HVAC equipment
- Exhaust systems
- Solar panels
- Communications equipment
- Mechanical units
Every rooftop visit places additional wear on the roofing system.
BUR systems are known for their durability under regular rooftop traffic, but designated walkways and preventative maintenance still help minimize unnecessary wear.
Maintenance Is Critical
No commercial roof should be installed and forgotten.
Routine maintenance allows building owners to identify developing issues before they become expensive repairs.
Professional inspections often evaluate:
- Surface condition
- Flashing details
- Roof penetrations
- Drainage systems
- Expansion joints
- Mechanical curbs
- Previous repair areas
- Evidence of moisture intrusion
Many commercial roof failures result not from the roofing material itself but from years of deferred maintenance.
Repairing a Built-Up Roof
One advantage of BUR systems is that localized problems can often be repaired without replacing the entire roof.
Repairs may address:
- Isolated leaks
- Flashing deficiencies
- Surface damage
- Mechanical penetrations
- Drainage concerns
The earlier these issues are identified, the more likely repairs can remain localized.
Waiting until widespread deterioration develops often limits repair options.
When Is Replacement Necessary?
Like every roofing system, BUR eventually reaches the end of its service life.
Replacement may become appropriate when:
- Repairs become increasingly frequent.
- Moisture has spread beneath the roofing assembly.
- Drainage deficiencies become widespread.
- Structural components have deteriorated.
- The roof no longer provides reliable long-term protection.
A professional condition assessment helps determine whether continued repairs remain cost effective or whether replacement represents the better long-term investment.
Common Misconceptions About BUR
Several misconceptions continue to surround built-up roofing.
“Built-up roofs are outdated.”
BUR remains a highly respected roofing system with decades of proven performance.
Many buildings continue to use it successfully because of its durability and reliability.
“More layers make the roof maintenance free.”
Multiple layers improve redundancy, but every commercial roof still requires regular inspections and preventative maintenance.
Ignoring small issues eventually shortens the life of any roofing system.
“A leak means the entire roof has failed.”
Not necessarily.
Many leaks originate from flashing, drainage issues, or localized deficiencies rather than widespread membrane failure.
Professional inspections help determine the true condition of the roofing assembly.
Choosing the Right Roofing System
BUR is one of several excellent commercial roofing options.
Selecting the right system depends on factors including:
- Building use
- Roof design
- Budget
- Long-term ownership plans
- Maintenance strategy
- Existing rooftop equipment
- Drainage design
The best roofing recommendation always considers the complete building rather than focusing on a single product.
Conclusion
Built-Up Roofing has protected commercial buildings for generations because of its durability, layered construction, and dependable long-term performance. While newer roofing systems continue to evolve, BUR remains an excellent solution for many low-slope commercial buildings throughout New Brunswick when properly installed, maintained, and inspected. Like every commercial roof, its success depends on proactive maintenance and thoughtful asset management.
At Altitude Roofing, we help commercial property owners, facility managers, municipalities, and developers throughout Fredericton and New Brunswick evaluate existing BUR systems, plan long-term maintenance strategies, and determine when repairs or replacement provide the greatest value. Our focus is helping you maximize the life of your roofing investment while protecting the people and operations beneath it.
Frequently Asked Questions
Built-up roofing is a multi-layer flat or low-slope roofing system consisting of alternating layers of bitumen (asphalt or coal tar) and reinforcing fabrics, topped with a protective surface layer of gravel or a cap sheet. The result is a thick, durable membrane that has been used on commercial buildings for more than 100 years. Its multiple layers provide redundancy — if one layer develops a defect, the others continue providing protection.
A properly installed and maintained BUR system typically lasts 20 to 30 years. The lifespan depends on the number of plies, installation quality, maintenance history, and the specific conditions the roof experiences. Regular inspections and prompt repairs of minor issues significantly extend BUR roof lifespan.
Yes. BUR systems have a long track record in cold Canadian climates. The multi-layer construction provides good resistance to temperature extremes, freeze-thaw cycles, and moisture. The key is proper installation — including appropriate drainage design, correct material selection for the climate, and attention to flashing details at all roof penetrations and perimeters.
BUR offers proven durability and good puncture resistance from its multiple layers, but it's heavier than single-ply systems and requires more specialized installation. TPO and EPDM are lighter, faster to install, and increasingly popular. The best choice depends on your building structure, budget, maintenance preferences, and the specific performance requirements of the application.
BUR roofs should be inspected twice per year — spring and fall — and after significant storm events. Maintenance includes clearing debris from drains and gutters, inspecting flashing and perimeter details, checking for blistering or cracking in the membrane, and ensuring drainage is functioning properly. Prompt repair of minor defects prevents water from penetrating the membrane layers.
