Built-Up Roofing (BUR) – Everything You Need to Know

Are you looking for a durable and economical roofing solution? A built-up roofing system (BUR) may be what you are looking for.

newimageroofingatlanta.com gathered information on built-up roofing systems (BUR), its benefits, installation, maintenance, and how it compares to other popular roofing systems. Consider the following:

What is Built-Up Roofing (BUR)?

Built-Up Roofing (BUR) is a time-tested, staple roofing system in the construction industry. This roofing system is composed of multiple layers of bitumen (asphalt or coal tar) and reinforcing fabrics, typically fiberglass or organic felts. These layers are applied in a repetitive fashion, creating a seamless, durable membrane. Gravel or mineral granules are often embedded into the top layer to protect it from the elements and provide significant UV resistance.

BUR Installation

Installing a built-up roofing system is a somewhat labor-intensive process that requires the expertise of skilled roofing contractors. Here is a step-by-step guide to how BUR is installed:

1. Deck Preparation – The process begins with preparing the roof deck, ensuring it is clean, dry, and in good condition. Existing roofing material is removed, and any necessary repairs are made.
2. Vapor Barrier Installation – A vapor barrier is installed to prevent any moisture from entering the building through the roof. This layer is essential for maintaining a comfortable indoor environment.
3. Insulation – Insulation is added to improve energy efficiency and temperature control. Insulation can help reduce heating and cooling costs.
4. Felt Layers – The first layer of roofing felt is applied directly over the insulation. This is typically a base sheet, and is secured using hot asphalt or adhesive.
5. Bitumen Application – Multiple layers of bitumen are applied over the base sheet. The bitumen is heated and spread evenly across the roof, followed by the application of a reinforcement fabric.
6. Reinforcement Fabric – Fiberglass or organic felts are embedded into the hot bitumen. This adds significant strength and stability to the roofing system.
7. Repeat – Steps 5 and 6 are repeated until the desired number of layers is achieved. A BUR system typically consists of three to five layers.
8. Surface Layer – The top layer or cap sheet, is made of bitumen and covered with aggregate materials like gravel or mineral granules. This layer provides protection against weather and UV radiation.
9. Final Inspection – After the surface layer is installed, a final inspection is performed to ensure that the roofing system is correctly installed, and there are no defects.
10. Maintenance – Regular maintenance is essential for a BUR system to maximize its lifespan and performance. Periodic inspections, cleaning, and repair of any damaged areas are crucial to its long lifespan.

BUR Advantages

Built-Up Roofing has several advantages contributing to its enduring popularity:

• Proven Durability – BUR systems are known for their long lifespan, often exceeding 20 years or more with regular maintenance. The roofing system’s multiple layers and redundancy make it resistant to leaks and damage.
• Waterproofing – The bitumen layers and reinforcing fabrics create a seamless, waterproof barrier that effectively protects the building from any water infiltration.
• Thermal Performance – The insulation layers in BUR systems can enhance a building’s energy efficiency, reducing heating and cooling costs.
• Fire Resistance – BUR systems can be made with fire-resistant materials, making them an excellent choice for buildings in regions prone to wildfires or with strict fire codes.
• UV Resistance – The top layer of aggregate materials offers UV protection, extending the roofing system’s lifespan.

BUR Disadvantages

While Built-Up Roofing offers multiple benefits, it also comes with some drawbacks:

• Installation Complexity – BUR installation is labor-intensive and requires experienced roofers. This can increase the initial installation cost.
• Weight – BUR systems can be heavy, potentially requiring additional structural support for some buildings.
• Maintenance Requirements – Regular maintenance is crucial to ensure a BUR system’s longevity, which can add to the overall cost of ownership.
• Odor and Fumes – The installation process involves heating bitumen, which releases unpleasant odors and fumes. Proper ventilation is necessary during installation.

TPO and PVC Roofing System Comparison

To make an informed decision about your roofing system, it’s essential to compare BUR to other popular options, like Thermoplastic Polyolefin (TPO) and Polyvinyl Chloride (PVC) roofing systems.

TPO Roofing Vs. BUR

TPO roofing is a single-ply membrane roofing system made from a blend of rubber and other materials. Here’s how it compares to BUR:

• Installation – TPO roofing is relatively easier and quicker to install compared to BUR, which can significantly reduce labor costs.
• Durability – BUR is known for its durability and long lifespan, often exceeding TPO systems. TPO can be more vulnerable to punctures and tears.
• Energy Efficiency – TPO roofing reflects sunlight effectively, helping reduce cooling costs. However, BUR systems with added insulation can achieve similar energy efficiency.
• Cost – TPO roofing can be cost-effective in terms of installation, but BUR may provide better long-term value due to its durability.

PVC Roofing Vs. BUR

PVC roofing, like TPO, is a single-ply membrane roofing system made of polyvinyl chloride. Here’s how it compares to BUR:

• Installation – PVC roofing installation is similar to TPO (ease and speed). It may be a more cost-effective option for initial installation.
• Durability – BUR is often considered more durable and resilient against severe weather conditions. PVC roofing may be more prone to damage over time.
• Energy Efficiency – PVC roofing has excellent UV resistance and reflects sunlight effectively, providing energy savings. However, BUR can achieve similar results with added insulation.
• Cost – PVC roofing can be cost-effective for initial installation, but BUR offers better long-term value and longevity.

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Built-Up Roofing Systems

In this article, you discovered what built-up roofing is, how it is installed, its advantages and disadvantages, and how it compares to other low slope roofing systems.

Understanding the various roofing system qualities, advantages, and disadvantages allows you to make an informed decision when determining which roofing system is best suited for your needs.

Unfamiliarity with roofing system advantages and disadvantages may lead you to installing an overpriced or improper roof on your residential or commercial structure.

Sources:
nps.gov/crps/tps/roofingexhibit/composition.htm
gsa.gov/real-estate/historic-preservation/historic-preservation-policy-tools/preservation-tools-resources/technical-procedures/types-of-flat-roofing-and-factors-affecting-its-deterioration
asphaltroofing.org/bur-multi-ply-built-up-roofing/