Built Up Roofing

Built Up Roofing consists of multiple piles of roof felts laminated together with bitumen. Built Up roof material can consist of bitumen-saturated felt, coated felt, polyester felt, or other fabrics. A surfacing is generally applied, including asphalt, aggregate (gravel or slag), emulsion, or a granule-surfaced cap sheet.

Built Up Roofing is one of the oldest and most reliable ways of installing a new roof. It was first known as composition roofing and started in the 1840’s. B.U.R.’s come in two basic types, asphalt and coal tar, with three basic components:

1. the waterproofing component
2. the reinforcing component
3. the surfacing component which is used to protect the other components from the elements

The roofing membrane is protected from the elements by a surfacing layer, which can be a cap sheet or gravel embedded in bitumen or a liquid-applied coating material. The most common surface for a BUR system, particularly in the west, is a fiberglass mineral surfaced cap sheet (pictured). The west represents 40 percent of the fiberglass cap sheet market. It has a white granular look, it is cost-effective, and is relatively maintenance-free.

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Modified Bitumen Roofing

Modified Bitumen was first developed and utilized in Europe in the 1960s. This membrane is manufactured in uniform sheets composed primarily of polymer-modified bitumen reinforced with one or more plies of fabric, or ply sheets. The fabrication can include polyester, glass, or a combination of the two. When applied in roofing, the finished version may be composed of several sheets of modified bitumen and asphalt to create a uniform matrix.

When used in conjunction with a thermoplastic polymer, APP (Atactic Polypropylene), a uniform matrix is created within the modified bitumen sheets. This matrix increases the bitumen’s resistance to ultraviolet (UV) light, increases its flexibility in extreme temperatures, and increases its resistance to water penetration. This added resilience and enhanced durability under extreme conditions make modified bitumen a prime choice when there may be movement or deflection of the underlying deck of a roof.

Modified Bitumen roofing systems create watertight barriers that perform for many years at a time due to the multiple layers of protection. When built up, these layers of bitumen exhibit exceptional resistance to the conductivity of heat between the exterior and interior of the building. This generates a noticeable reduction in heating and cooling costs. The thermoplastic polymers used in the modified bitumen make it more fire-resistant as well. The technology employed in creating this roofing system makes it affordable and easy to generate as well.

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