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Know Your Roof: Built Up Roof (B.U.R.)

Jun 23, 2018

B.U.R. “The Cadillac of Roof Systems”.

Brief SummaryB.U.R. is an acronym for Built up RoofsThe Cadillac of Roof Systems”.  If you have an older, low rise commercial or industrial building in Toronto. Most likely you have a B.U.R. system installed on your building. B.U.R. membranes are handcrafted layer by layer like a lasagna. Crown Industrial Roofing was built (Pun intended) on B.U.R. systems and we have been working on them for the past 40 + years.

Trust Crown and call us today to help you with your Commercial or Industrial Built Up Roof system.

Phone: 416-744-7788


Built up roofs often referred to by the acronym B.U.R., was developed in the England almost 200 years ago. These roof systems are sometimes also referred to as “tar and gravel” roofs. B.U.R. roof is generally composed of layers of bitumen and reinforcing fabrics that create a finished roof. Crown Industrial Roofing has been doing B.U.R. system for 40+ years. We are Toronto’s leading experts on Built Up Roof membrane for Commercial and Industrial Flat Roofs.

How Is It Built Up?

As we discussed earlier, B.U.R. membrane is created by layering bitumen and reinforcing fabric, almost like a Lasagna. The number of layers in a cross section is the number of plies on a roof. The reinforcing fabric is called roofing felts.

The bitumen used in Built Up Roof is asphalt. The asphalt is heated in a kettle or tanker and then applied by a mop or mechanic spreader. The asphalt serves as both the system adhesive and the waterproofing agent. The bitumen is then topped with aggregate to protect the asphalt from UV radiation and wind uplift.


B.U.R. membrane is a long-lasting roof and it can be expected to last 25-30 years with regular inspections and maintenance.  There is also an added benefit of Built Up Roof is that does have some Self-Healing properties, which means less repair requirements compared to the new single ply roofs.

Built Up Roof unlike a lot of the new roofing membranes is quite resilient to branch, debris damage and foot traffic.

B.U.R. also allows for a “rehabilitation or reroof” of the membrane which can be significant cost savings for a building owner.


B.U.R. membrane requires experienced and well-trained roofers to ensure proper installation. It is near impossible for an amateur to create a Built Up Roof membrane that would meet the exact standards of a professional Commercial roofing company like Crown Industrial Roofing.

The process of building a B.U.R. system on building is labour and time intensive process. These roofs are not “quick jobs”, time and care is required while each layer is being installed.

For these reasons, B.U.R. membrane can be more expensive for the initial install than the TPO and EPDM systems(we will discuss them in the upcoming posts). The resilience and longevity of the B.U.R. system does end up making the Built Up Roof system the economical choice in the long run.

In Conclusion

Built Up Roof system is almost a 200-year-old method of Handcrafting Flat Roofs for Commercial or Industrial building.  When installed properly they are long lasting and quite resilient to the elements. B.U.R. install, or repair does require an experienced crew that understands Built Up Roof membrane. Crown Industrial Roofing is Toronto’s B.U.R. System Specialist!

Call Today for all your B.U.R. system needs (Inspection, Maintenance, Repair, or Replacements)

Get your FREE Roof Inspection and Book Today

Phone: 416.744.7788