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What are built up roof layers called?

A built-up roof (BUR) consists of multiple layers of asphalt or tar-saturated felt, applied in alternating layers and then surfaced with gravel, crushed stone, or other material. The layers of saturated felt are called felt courses and are typically installed four to six plies deep.

The greater number of layers, the greater the protection against weather elements like wind and rain. The top layer of a built-up roof is known as the cap sheet and is either poured black asphalt or a layer of specially formulated modified bitumen.

The top surface is then topped off with a layer of the desired surfacing material to protect the asphalt. Typically this includes a base layer of tar and a layer of gravel, crushed stone, or other material.

In some cases, the entire roof may be coated with elastomeric coating or acrylic-like material.

What materials are in a built up roof?

A built up roof (BUR) is a type of roofing system that is composed of multiple layers of asphalt and reinforcing materials, such as felt, fiberglass or organic mats. This type of roofing is common on flat or low-sloped roofs, and is especially popular on commercial roofs.

The water-resistant layers of a BUR are made up of alternating layers of hot, asphalt-saturated materials, such as tar paper and roofing felt. Asphalt is used to waterproof and adhere the roofing layers together.

The asphalt also acts as a solvent to the reinforcing layer, which gives added strength. On top of the asphalt layers is a protective layer of aggregate, such as gravel, slag, crushed stone, and/or coated granules.

In a built up roof system, two or more layers of asphalt are typically added to the foundation layer. The number of layers and type of asphalt used depend on the roof’s size, shape, and slope. In addition to the asphalt, what materials are in a built up roof depend on the roof’s application and condition.

This could include roofing felt, fiberglass or organic mats, mineral stabilizers, and other reinforcing materials. Finally, one or more layers of mineral granules can be applied as a protective surface.

The granules protect the asphalt layers from exposure to air and ultraviolet light.

Overall, there are a variety of layers and materials that make up a built up roof system. The components of each specific roof will vary based on the geography and application, but the common components of a BUR include asphalt, reinforcing materials, and a protective surface of aggregate.

How thick is built up roofing?

The thickness of built up roofing depends on several factors. It is typically between two and six inches thick when installed. The number of layers or “plies” of roofing material used will influence the thickness – typically two to four plies installed for flat roofs and up to six plies for sloped roofs.

The type of materials used will also factor into the thickness of the roof system – felt paper, asphalt, and gravel are the most common materials used in built up roofs. The final factor that impacts the thickness of built up roofing is the climate and weather conditions in your area.

In climates with colder temperatures, multiple layers make the roofing system more resistant to damage from harsh weather conditions.

Is TPO built up roof?

No, TPO (Thermoplastic Polyolefin) is not built up roof. It is a single-ply roofing membrane made from ethylene propylene rubber and polypropylene blended together and reinforced with a polyester scrim or other reinforcing fabric to give it strength.

TPO offers the effectiveness, flexibility, and durability of rubber roofing but with a much lower cost and lighter weight than traditional built up roof systems. TPO offers enhanced resistance to weathering, ozone, sunlight, and extreme temperature.

It is also Energy Star compliant and helps reduce the urban heat island effect.

Are built up roofs used for flat roofs?

Yes, built up roofs (also known as tar and gravel roofs) are often used for flat roofs. A built up roof consists of layers of asphalt, tar, and gravel built up over roofing felt and roof deck. The asphalt and tar serve as the waterproofing membrane, while the gravel protects the roof from UV rays, provides additional waterproofing and helps shed water away from the roof deck.

This type of roof is best suited for flat and low-sloped roofs and provides an economical, durable and long-lasting waterproofing solution. It is also relatively low maintenance and can last as long as 20-30 years with proper maintenance.

If flat roofs are in a colder climate, they may require additional insulation and weather-proofing to prevent ice and snow buildup, as well as damage from the freeze/thaw cycle.

What are the different types of flat roofs?

Flat roofs are a common roofing solution for many buildings, both residential and commercial. Each with their own unique benefits and drawbacks.

The most common type of flat roof is known as the Built-Up-Roof (BUR), or the foam-based roof. This type of roof is made up of multiple layers (usually three or more) of either felt paper or fiberglass membrane, which are laid in place and then covered with asphalt, tar, or a combination of both.

The BUR offers great protection from harsh weather elements, is relatively inexpensive, and is relatively easy to install. The downside of this type of roof is that it needs to be maintained regularly to ensure its integrity, with most roofers recommending it be replaced every ten to fifteen years.

Single-ply membranes are the most popular flat roofing options for commercial building owners. Such as EPDM (ethylene propylene diene monomer), TPO (thermoplastic olefin), and PVC (polyvinyl chloride).

These membranes are applied in large sheets (often 20x100ft) and can be extremely weather resistant. Single-plys also require less maintenance and last longer than BURs, with an average life of around 20-30 years.

Green Roofs are a newer flat roof solution that has quickly been gaining in popularity. This type of roof includes an additional layer of vegetation such as grass or small shrubs, which reduces the heat island effect, improving insulation and energy efficiency.

The downside to green roofs is that they require quite a bit more investment upfront, as well as continual maintenance during their life.

Finally, there is the Metal Roof system. Most often used on commercial buildings, metal roofs are lightweight, durable and highly weather resistant, and are designed to last for up to 50 years before needing to be replaced.

However, metal roofs tend to be more expensive upfront, as well as more difficult to install, making them a less common option for flat roofs.

How long do built up roofs last?

Built-up roofs, also known as tar-and-gravel roofs, have been used for well over a century as an affordable way to protect commercial properties from the elements. When properly constructed and maintained, built-up roofs have a lifespan of up to 20 years, or potentially longer if they feature additional elements such as a cooling membrane or UV protection.

The life of a built-up roof depends largely on the quality of materials and severity of climate the building is in, as well as the appropriate maintenance and repair performed throughout the life of the roof.

While some materials used to construct built-up roofs can initially be costly, they are among the most cost-effective types of roofing in the long run due to their durability and long lifespan.

Is a built up roof the same as modified bitumen?

No, a built up roof and a modified bitumen roof are not the same. A built up roof consists of alternating layers of bitumen (tar), a waterproofing material, and reinforcing fabric, usually fiber glass.

The layers are applied by torch or hot asphalt or cold adhesive and are also known as “tar and gravel” roofs because they are composed of a gravel surfacing. Modified bitumen roofing is composed of asphalt and other modifiers such as polymers that make the roof more resistant to extreme temperatures, high winds, and chemical exposure.

Modified Bitumen roofs are usually surfaced with a mineral granule or a smooth coating and the composition of the material is different than traditional “tar and gravel” built up roofs.

What are bitumen roofs?

Bitumen roofs are roofs made from bitumen, a black and gummy material that is also known as asphalt. A bitumen roof is usually composed of layers of reinforced fabric or mats that are impregnated with bitumen and applied onto the roof.

The bitumen acts as a waterproofing layer and provides the roof with protection against moisture, ultraviolet radiation, and wear. Bitumen roofs are durable—they can last up to ten years before they need to be replaced—yet they are lightweight, making them an ideal choice for flat or low-slope roofs.

Bitumen roofs work best in warmer climates where the sun’s ultraviolet rays can help keep the material in good condition. They are also highly fire-resistant, so they are often a better choice than other materials in terms of safety.

Although they are not as aesthetically pleasing as other types of roofs, they are easy to install and maintain, and they require little upkeep throughout their life.

What is the difference between built up roofing and single ply roofing?

Built up roofing (also known as BUR) and single ply roofing systems are two different types of flat roofing systems commonly used in commercial and industrial applications. Built up roofing (BUR) is a method of installation in which multiple layers of asphalt-saturated felt, along with reinforcing fabric, asphalt, and gravel, are installed to form a continuous membrane.

The overlapping of the felt layers is completed with hot asphalt and provides a great amount of resistance to water penetration, which makes it one of the toughest and most reliable commercial roof systems available.

Single ply roofing systems use a single sheet or membrane of material that is mechanically fastened or glued to the existing roof deck to form a continuous, waterproof layer. The single layer of material is typically composed of materials like thermoplastic polyolefin (TPO), ethylene propylene diene monomer (EPDM) rubber, or polyvinyl chloride (PVC).

Single ply roofing systems are generally easier to install than built up roofing systems, and are often chosen when cost and efficiency are top priorities. Single ply roofing systems provide superior waterproofing properties and can be more cost effective over the long run, but typically lack the resistance to puncture and the overall longevity that BUR systems offer.