What is built-up roof covering?

Built-up roofing, also called BUR, is the most common roofing material used on low-slope roofs. It is composed of alternating layers of reinforcing fabric and bitumen (asphalt) and is finished with a top layer of aggregate, such as stone or gravel.

What is a built-up roof mean?

Built-up systems are installed by alternating layers of asphalt or tar and supporting fabrics directly onto the roof. You can choose the number of layers (or plies) that are installed. The final layer of a built-up roofing system consists of stone or gravel.

What are the layers of a built-up roof?

Built-up roofing systems are most commonly applied with three or four layers of roofing materials to make up the complete roofing system. These layers are typically a base sheet, a fiber sheet, and then either one or two layers of bitumen.

What is a built-up roof bur?

As a system, built-up roofing (BUR) is a type of asphalt roofing that has been around for more than 100 years. It is one of the most common materials used on low-slope or flat roofs. EASY TO APPLY: Offered in Ply IV (4) and Ply VI (6) asphalt-impregnated roofing felts, which provide durability and ease of application.

How long do built up roofs last?

Built-Up Roof (BUR)

The average lifespan of BUR is 20 to 30 years, depending on the climate and the particular materials that it’s made of. Still, there are specific constructions that can last up to 40 years.

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

Built-up systems are installed by alternating layers of asphalt or tar and supporting fabrics directly onto the roof. You can choose the number of layers (or plies) that are installed. Single-Ply Membrane Roofing Systems have been the go-to roofing for commercial, industrial, and manufacturing facilities for decades.

How do you install a built-up roof?

First, contractors attach base sheets to the roof’s subsystem using roofing nails. Then, they use tar, concrete, adhesive, or asphalt to glue down felt over the top of the base sheeting. Next, roofers install a layer of gravel or cap sheets, which they then cover with a final layer of asphalt.

What is a 3 ply built-up roof?

A 3-Ply Hybrid BUR differs from other membrane options due to its combination of a 1ply base sheet with two plies of glass felt that enhances the performance of the membrane with a quicker installation time and less weight on the roofing system itself.

How is built-up roofing applied?

ARMA defines a built-up roofing system as a roof where multiple layers of asphalt alternated with ply sheets (felts) are applied over the roof deck (vapor retarder) and, most often over insulation that is attached to the roof decking.

What is the difference between built-up roofing and modified bitumen?

Modified Bitumen (MB) roofing is an asphalt-based, close cousin of the Built-up-Roof (BUR) designed for buildings with low-slope or “flat” roof structures. Modified Bitumen roofs give designers and installers an even broader array of options than BUR.

What is a SBS roof?

SBS modified bitumen roofing is a material made out of asphalt and synthetic rubber, making it an exceptionally flexible material for flat roofs. Thanks to its rubber composition, the material is less prone to cracking and sustaining damage from elements like ice and sun.

What is PVC roofing?

What is PVC roofing? Made from polyvinyl chloride (or in layman’s terms, plastic), PVC is a great single-ply roofing solution. It’s made from a lower percentage of oil and petroleum than thermoplastic polyolefin (TPO) or ethylene propylene diene terpolymer (EPDM).

How thick is a built up roof?

On average, Built Up Roofs are generally anywhere from about 2 to 4 inches, but they can be thicker depending on the amount of asphalt that is applied in each layer during installation.

Why is it often difficult to identify flaws in the membrane of a built up roof?

Why is it often difficult to identify flaws in the membrane of a built-up roof? The gravel coating conceals the membrane. What is the purpose of the asphalt and the felts in a built-up roof system? The asphalt is the waterproofing material.

What is 4 ply built up roofing?

A 4-Ply roofing system involves roofing felts that are typically four plies composed of layers of reinforcement such as fiberglass or polyester felts, with each ply being embedded in a full bed of hot asphalt/bitumen.

What lasts longer bitumen or EPDM?

EPDM has a life expectancy of 50 years, comparing incredibly well to its bitumen felt competitors. The average guarantee a company will provide when installing EPDM on a residential client’s property is 20 years.

Which type of flat roof covering has the longest lifespan?

Lightweight single-ply roofing can last for as long or longer than layered roofs depending on the properties of the material, the design of the roof and reliance on commercial roof repair. EPDM and TPO roofing generally last anywhere from 10 to 20 years, while TPO roofs have stronger seams than EPDM roofing.

What is the best type of flat roof?

EPDM Membranes

Quite possibly the best flat roofing membrane, EPDM is a relatively low-cost flat roof material that offers a number of significant advantages. Clean, straightforward installation, incredible strength, a long lifespan, and a smart finish combine to make EPDM membranes a difficult one to beat.