What to expect from a torch-on flat roof installation project

Torch-on flat roofing, aka torch-down flat roofing has traditionally been one of the most popular roofing options among businesses in Vancouver. The advantages of this style of roof include durability, flexibility, and superior weather protection. It lasts 25 years or more and repairs are relatively easy to fix, making it a cost-effective option. Here’s more information as well as what to expect from a torch-on flat roofing installation project.

What materials does torch-on roofing use?

Torch-on roofing uses sheets of modified bitumen (made from asphalt). There are two main types of bitumen: APP (a form of plastic) and  SBS (a form of rubber).These are composed of 5 layers: 

• Thermo-fusible film

• Bitumen (APP or SBS)

• Reinforced polyester 

• Bitumen (APP or SBS)

• Mineral surface. 

APP (atactic polypropylene) is easier to install because of its free-flowing liquid melting properties, and SBS (which has sticky melting properties) is quicker to install and provides more flexibility due to its rubber nature.

How is a torch-on flat roof installed?

This type of flat roof installation uses a flaming torch (powered by a propane tank) to heat rolls of bitumen. The heated bitumen will adhere to the roof and create a waterproof seam to keep the elements out. This roofing system is installed in layers.

• Insulation is installed first, mechanically ie. screws, or adhered with glue or a hot mop.

• Vapor barrier is applied next to help protect the roof from condensation and moisture.

• Overlay board is then laid down as the surface to which the modified bitumen will adhere.

• The base sheet of bitumen forms the first layer.

• One or two cap sheets form the 2nd, and optional 3rd layer. Three layers offer more durability, energy efficiency and weather protection than two.

• Flashing is added around equipment that penetrates the roof (HVAC units, vents, etc.)

The disadvantages of torch-on flat roofing include the danger of working with an open flame, susceptibility to damage from foot traffic, the possibility of trapping water between the layers and incomplete sealing of the seams. Avoiding these issues is paramount and thus the reason why it’s important to work with a professional torch-on roofing company in Vancouver.

Laurentian Roofing professionals are your residential torch-on roofing experts! Our insurance coverage includes open flame heat application, making us one of the most trusted residential torch-on roofing companies in BC. Contact us today for a free estimate!