Tar and Gravel Roof Repair, Restoration and Replacement
Many older commercial and multi-family buildings in Calgary still have tar and gravel roofs, also called built-up roofing (BUR). These roofs can last a long time, but once they start leaking, finding the source under the gravel takes experience. Iron Shield Roofing repairs, restores and replaces tar and gravel roofs, and we can convert them to modern membrane systems when the time comes. Call (403) 471-9023 to book an inspection.
What Is Built-Up Roofing?
Built-up roofing gets its name from the way it is made: several layers of bitumen and reinforcing felts are applied one on top of the other to create a thick, redundant waterproofing membrane. A final flood coat of hot asphalt is applied and gravel is embedded in it. The gravel protects the membrane from UV, foot traffic and hail, and adds weight that helps hold the system down in high winds.
BUR systems were the standard for flat commercial roofs for decades, which is why so many Calgary buildings built before the 1990s still have one. When they are maintained, they can perform well for 20 to 30 years.
What Goes Into a Built-Up Roof?
A built-up roof is a system of components that work together. IKO manufactures a full line of BUR products, including:
IKO Modified Vapour Protector (MVP)
A vapour barrier installed over the deck to stop warm, moist indoor air from reaching the insulation.
Base Sheets
Asphalt-saturated felts used as the first ply in the system, coated on both sides for added protection. IKO base sheet options include:
- Modiflex MP-180-SS-Base
- Modiflex MF-95-SS
IKOTherm Insulation
Rigid polyiso insulation that keeps the building comfortable, cuts energy loss and provides a solid base for the roofing plies.
IKO Asphalt
Bulk asphalts used to bond the plies and form the flood coat. Options include:
- Type 1 Asphalt
- Type 2 Asphalt
- Type 3 Asphalt
- Modi-Melt SEBS Asphalt
- Easy-Melt 200
Benefits of Built-Up Roofs
Multiple Layers of Protection
Several plies mean that if the top layer is damaged, the layers below keep water out.
Tough and Long Lasting
The gravel surface protects the membrane from UV, hail and foot traffic, and a maintained BUR roof can last for decades.
Strong Fire Resistance
The gravel surface gives tar and gravel roofs excellent fire resistance.
Tar and Gravel Roofing in Calgary: Frequently Asked Questions
Questions owners ask about older built-up roofs.
Can a leaking tar and gravel roof be repaired?
Usually, yes. We move the gravel back, find the failed area, repair it with compatible materials and replace the gravel.
Should I replace tar and gravel with a membrane?
If the roof is near the end of its life or leaking in many places, replacing it with SBS, TPO or EPDM is often the better long-term value.
How long does a tar and gravel roof last?
A well-maintained built-up roof often lasts 20 to 30 years.
