What Are The Most Common Types Of Materials Used For Flat Roofs?

Whether your flat roof installation and repair needs are for a commercial, industrial or residential structure, there will be several factors to consider with respect to the type of roofing material used as well as their associated costs at the time of installation and over the duration/lifespan of the roof. 

Specifically, the common types of flat roof materials used by commercial or residential roofing companies in Toronto include:

Traditional Tar-and-Gravel – Also known as built-up roofing or BUR

  • Three (or more) alternating layers of waterproof material and hot tar
  • Capped with a layer of smooth stone

Modified Bitumen – Peel-and-stick format

  • A reinforced material (styrene and butadiene) that is cut and rolled into place
  • Combines the advantages of built-up roofing with a single-ply application
  • Adheres itself to the surface as the backing is removed during rolling

Modified Bitumen – Torch applied or heat welded

  • Also a reinforced material (polypropylene) that is cut and rolled into place
  • In this case, the adhesive must be heated as the material is rolled out

Rubber Membrane

  • A durable material similar to that of an inner tube or a hot water bottle
  • Must be fastened or secured with anchor bolts, a layer of stone, or glue

Your choice of flat roof material, and its particular pros and cons, will have an impact on such factors as:

  • Initial installation costs
  • Repair and maintenance
  • Durability and longevity

The pros and cons of these flat roof materials will be outlined in the following section.

Advantages And Disadvantages Of The Various Types Of Flat Roof Materials 

In general terms, there are both advantages and disadvantages to installing a flat roof compared to a sloped roof, regardless of the actual type of material chosen.  These can be summarized as follows:

Advantages of a Flat Roof

  • Typically easier to install
  • Usually less expensive to install
  • More usable space or living space inside the structure

Disadvantages of a Flat Roof

  • Additional monitoring, maintenance and/or repair will be required
  • More prone to leaks therefore insurance rates may be higher
  • There is more surface area with constant exposure to the elements

On an individual materials basis, these are the major pros and cons relative to flat roof installation or repair that you should discuss with your commercial roofing company:

Traditional Tar-and-Gravel

  • Pro: very good fire retardant
  • Pro: least expensive of the various materials
  • Con: may require joist reinforcement due to its weight
  • Con: difficult to trace the source of any leaks

Modified Bitumen (styrene and butadiene)

  • Pro: heat-reflective material saves on energy (cooling) costs
  • Pro: relatively easy to install – could be a do-it-yourself project
  • Con: comparably more expensive than tar-and-gravel
  • Con: subject to tearing and scuffing, leading to potential leaks

Modified Bitumen (polypropylene)

  • Pro: similarly, a heat-reflective material that reduces energy costs
  • Pro: durability – very robust quality
  • Con: structure must be evacuated during installation due to possible fire hazard
  • Con: also can be subject to tearing and scuffing

Rubber Membrane

  • Pro: relatively light material that is easy to install
  • Pro: resistant to tearing and scuffing – leaks are easy to patch
  • Pro: longevity – able to withstand extreme weather conditions/cycles
  • Con: more expensive than the other materials
  • Con: more vulnerable to punctures
  • Con: heat-absorbent material (black is often the standard colour)

If you are looking for a Toronto roofing company to provide flat roof installation or repair services, call Avenue Road Roofing today at 416-785-5129!