Built-up roofs (BUR) have been a reliable solution for commercial buildings for well over a century. Originally developed in the 1840s, modern BUR systems have evolved into more durable, long-lasting assemblies that offer excellent protection when properly maintained.
If your building features a BUR system, timely built-up roof repair is essential to prevent costly leaks, water intrusion, and structural damage. As these roofs age, various issues can arise—from blistering and cracking to membrane separation—each requiring a targeted repair approach.
How Do Built-Up Roofing Systems Work?
The built-up roof (BUR) system is straightforward in concept—a layered assembly designed for durability and longevity. Often described as a “roofing sandwich,” it consists of alternating layers of asphalt and reinforcing felt ply sheets, creating a tough, waterproof membrane. These layers are applied in stages, where the term “built-up” comes from.
Typically, the assembly is built over heat-resistant perlite insulation boards, with an additional insulation layer beneath and a metal roof deck at the base for structural support. The top layer, featuring materials like white reflective ply, smooth asphalt, gravel, or granule-coated membranes, can vary.
Signs Your BUR Roof Needs Repairs
Common signs that you need built-up roof repair include:
- Leaks inside the building
- Worn or discolored marks on the surface
- Missing gravel or membrane layers, exposing the asphalt and ply below
- Crushed or sagging sections of the roof
- Unevenness in the BUR roof assembly
- Missing sacrificial or protective layers under equipment like solar panels
- Cracking, blistering, and other damage to the BUR membrane
- Ponding water on the roof surface.
Common Issues and BUR Roof Repair Solutions
Built-up roofs (BUR) are known for their durability, but over time, they can develop issues that require targeted repairs. Depending on the specific assembly installed on your commercial building, you may encounter several common problems throughout its lifespan.
Loss of the UV Protective Layer
One of the most frequent problems with built-up roofing systems is the deterioration or loss of the top protective layer. This can include gravel ballast, asphalt coating, a granulated surface, or a reflective coating. Without this layer, UV rays can damage the asphalt and ply layers beneath, leading to cracking and leaks.
Solution: Periodic Reapplication, Parapet and Edge Wall Extensions
Regular maintenance—such as reapplying gravel, coatings, or installing a new membrane layer—protects the roof assembly. If wind displacement causes gravel displacement, extending parapets or edge walls may prevent further scouring and drainage blockages.
Damage to Seals and Flashing
Even if the BUR membrane is intact, failure of flashing or sealants around roof edges and penetrations can lead to leaks. Flashings and flexible seals naturally degrade due to exposure and weathering over time.
Solution: Repair Flashings and Replace Seals
Replacing damaged flashing and deteriorated seals is essential to maintain watertight integrity. Most roofs will require seal and flashing replacements multiple times over their lifespan to prevent widespread damage.
Penetration from the Aggregate Layer
Gravel used in some BUR assemblies can press into and damage insulation or roof decking—especially on roofs with softer materials like foam or perlite insulation—under heavy foot traffic or impact.
Solution: Removal of Crushed Insulation, Membrane Repair
Damaged insulation or decking must be removed, and the affected area rebuilt. After removing the gravel and crushed layers, our team installs a reliable patch to restore protection. Cleaning and replacing materials also helps when debris, algae, or plant growth cause damage.
Leaks and Cracks
Built-up roofing membranes can develop cracks and separations over years of temperature fluctuations and UV exposure. These allow water infiltration, which worsens when freezing temperatures expand the openings.
Solution: Sealing, Patching, or Replacement
Depending on the extent of the damage, we may recommend spot sealing, full patching, or membrane replacement. Delta’s team uses specialized tools to locate hidden leaks beneath gravel or granulated surfaces and delivers the appropriate repair solution for lasting performance.
Stay Vigilant: Protect & Maintain Your BUR Roofing System
Routine inspections and timely repairs are key to extending the life of your built-up roof. Here are a few maintenance tips:
- Inspect your roof at least twice a year, and after major storms
- Recoat the protective surface every few years to prevent UV damage.
- Clear debris from drains every season to prevent ponding
- Consider installing siphonic drains to improve water flow and avoid water accumulation
Delta Innovative Services is your trusted partner for built-up roof repairs in Kansas City. Whether dealing with minor surface wear or significant structural damage, we offer expert inspections, maintenance, and repairs to keep your commercial roof strong and leak-free.