How to Identify Built-up Roofs (bur) on Commercial Buildings

by

Built-up roofs (BUR) are a common roofing system used on many commercial buildings. Identifying a BUR can help property managers, contractors, and inspectors assess the roof’s condition and plan maintenance or repairs.

What is a Built-up Roof (BUR)?

A built-up roof is a traditional roofing system composed of multiple layers of bitumen (such as asphalt or coal tar) alternated with reinforcing fabrics like felt or fiberglass. These layers are then covered with a protective surface, such as gravel or mineral granules, to shield against weather elements.

Key Features to Identify a BUR

  • Layered Appearance: BURs typically have a multi-layered look, often appearing as a series of overlapping, tar-like surfaces.
  • Granular Surface: The top layer is often covered with gravel or mineral granules, providing a rough, granular texture.
  • Flat, Uniform Surface: The roof surface is generally flat and uniform, with seams between the layers often visible upon close inspection.
  • Presence of Flashings: Metal or other material flashings are common around roof penetrations and edges.
  • Age and Wear: Older BUR systems may show signs of aging such as cracks, blisters, or gravel loss.

Visual Inspection Tips

When inspecting a roof for a BUR, look for the following visual cues:

  • Multiple overlapping layers with a tar-like appearance.
  • Granular surface material that can be swept away to reveal the underlying layers.
  • Signs of wear such as cracks, splits, or areas where gravel has fallen off.
  • Black or dark brown coloration typical of bitumen-based systems.
  • Seams or overlaps that are visible from the ground or roof level.

Additional Identification Methods

If visual inspection is inconclusive, other methods include:

  • Reviewing building plans or maintenance records for roofing history.
  • Consulting with roofing professionals or contractors familiar with BUR systems.
  • Using a roof probe or core sample to examine the layers directly (requires professional assistance).

Identifying a built-up roof accurately ensures proper maintenance and prolongs the lifespan of the roofing system. Regular inspections can help detect early signs of damage and prevent costly repairs.