What Is a Built-Up Roof?

What Is a Built-Up Roof?

What Is a Built-Up Roof?

A built-up roof (BUR) is a type of roofing system that has been widely used for flat and low-slope roofs. Known for its durability and waterproofing properties, a built-up roof consists of multiple layers of materials that provide significant protection against the elements. The most common components of a built-up roof include bitumen, felts, and gravel or other protective surfaces.

What Is a Built-Up Roof System?

The built-up roofing system is characterized by its layered construction, typically featuring a combination of asphalt, tar, or coal tar pitch, along with reinforcing fabrics. Each layer is designed to enhance the roofing’s waterproofing, durability, and resistance to UV rays.

What Is a Built-Up Roof Made Of?

A built-up roof is typically made from the following materials:

Built-Up Tar and Gravel Roof

One common type of built-up roof is the built-up tar and gravel roof, which uses a combination of asphalt (or tar) and gravel. The gravel layer provides additional protection against weathering and physical damage, while also helping to dissipate heat.

Built-Up Hot Mopped Roof

Another variant is the built-up hot mopped roof, where hot bitumen is mopped onto the surface, bonding the layers together. This method is effective for creating a solid and waterproof seal, making it ideal for commercial buildings.

Built-Up Roof Types

There are several types of built-up roofs depending on the number of layers and materials used:

Built-Up Roof Membrane

The built-up roof membrane is the waterproof layer created by the combination of bitumen and felt. This membrane is crucial for preventing leaks and moisture infiltration, contributing to the overall lifespan of the roof.

Built-Up Roof vs. TPO

When comparing built-up roofs to TPO (Thermoplastic Olefin) roofs, several factors come into play:

Built-Up Roof Life Expectancy

The life expectancy of a built-up roof can range from 20 to 30 years, depending on factors such as climate, maintenance, and the materials used. Regular inspections and timely repairs can significantly extend the lifespan of a built-up roofing system.

Built-Up Roof Repair

Repairs to a built-up roof can vary based on the nature and extent of the damage. Common repair methods include:

1. Patching: Minor leaks or cracks can be patched with additional layers of bitumen or modified bitumen.
2. Resurfacing: If the roof surface is significantly worn, a new layer can be applied over the existing system.
3. Flashing Repair: Ensuring that flashings are in good condition is critical for preventing leaks at seams and penetrations.

Built-Up Roof Without Gravel

A built-up roof without gravel is often referred to as a smooth built-up roof. This type utilizes a layer of bitumen without the protective gravel layer. While it may be less durable against physical damage, it can still provide effective waterproofing.

Built-Up Composition Roof

The term built-up composition roof refers to roofs constructed from a variety of materials that make up the multiple layers, primarily focusing on the asphalt composition. This type of roofing system combines flexibility and durability, making it suitable for various climates.

R-Value of a Built-Up Roof Material

The R-value of a built-up roof material is crucial for understanding its insulation properties. The R-value measures thermal resistance, helping to determine energy efficiency. Generally, the R-value for built-up roofing systems can range from R-10 to R-30, depending on the insulation materials used in conjunction with the built-up layers.

Cost of Built-Up Roof

The cost of a built-up roof can vary widely based on factors such as location, materials, and labor. On average, the installation costs can range from $5 to $10 per square foot. While the initial investment may be higher compared to other roofing options, the long-term durability and low maintenance requirements can make it a cost-effective choice over time.

Built-Up Roofing Material

The primary built-up roofing materials include:

• Asphalt: Most common for its waterproofing properties.
• Fiberglass Felt: Offers strength and durability.
• Coal Tar Pitch: Used for its resistance to moisture and UV rays.
• Modified Bitumen: Enhances flexibility and performance.

Built-Up Roof System Thickness

The thickness of a built-up roof system can vary depending on the number of layers and the materials used. Typically, a 3-ply system may have a thickness of around 3 to 4 inches, while a 5-ply system could exceed 5 inches in thickness.

Built-Up Roof Definitions

Understanding the definition of built-up roof helps clarify its significance in the construction industry. A built-up roof is essentially a flat roofing system made up of multiple layers of materials, designed for durability and effective water resistance. This roofing type is particularly popular for commercial and industrial buildings due to its robustness and longevity.

Built-Up Roof Installation

The installation of a built-up roof involves several critical steps:

1. Surface Preparation: The roof deck must be clean and dry, ensuring proper adhesion.
2. Layer Application: Bitumen is applied in layers, alternating with felt for reinforcement.
3. Finishing Layer: A final layer of gravel or a smooth surface is applied for protection.

Benefits of Built-Up Roofs

Built-up roofs offer numerous benefits, including:

• Durability: The layered construction provides enhanced resistance to damage.
• Waterproofing: Excellent waterproofing capabilities make it ideal for flat roofs.
• Versatility: Can be customized for various applications and environments.
• Energy Efficiency: Potential for insulation improvement, lowering energy costs.

Built-Up Roof Details in PDF

For those seeking comprehensive specifications and technical data, built-up roof details in PDF format are often available from roofing manufacturers and industry standards organizations. These documents provide valuable insights into installation techniques, materials, and maintenance guidelines.

Summary of Built-Up Roofing Characteristics

By understanding what a built-up roof is and its various components, one can make informed decisions regarding roofing systems that best fit their needs, whether for residential or commercial applications. Its time-tested design offers a reliable solution for those looking for a durable and effective roofing system.