How is a Commercial Roof Constructed?

April 3, 2023

Complexity is the most significant difference between commercial roofs and residential roofs. Commercial roofing is more complex because of its size and design. Constructing a commercial roof requires more workforce, material, and time. This article explains essential details about commercial roofing. To learn more, continue reading. 

What is Commercial Roofing?

The term commercial roofing refers to the roofing systems installed on commercial buildings, such as shopping centers, office buildings, and other industrial facilities. Typically, these roofing systems are larger and more complex than residential roofs. Hence, these require specialized knowledge and skills to design, install, and maintain.

Roof materials for commercial buildings can vary depending on their specific needs and the climate of the area. Since more roofing material options are available for commercial roof systems than residential roofs, finding a reliable contractor who offers extensive commercial roofing services is essential to ensure the best results.

Steps Involved in Constructing a Commercial Roof

A commercial roof in Canada is typically constructed with several layers of materials to provide durability and weather resistance. Building designs, roof systems, and local building codes may affect the specific construction details. Construction of a commercial roof generally involves the following steps:

Design and Planning 

The first step to a successful roof design is selecting the right roofing system for a particular building. The roof slope, the building’s size, the climate, and the local building codes contribute to the design. 

Roof Decking 

The next step is to install the roof decking. These are installed over the building’s supporting structure to provide a base for the roof covering. The roof decking (or roof sheathing) consists of wooden boards that support the structure. Shingles and other roofing components are installed on these boards. Plank decking and sheet decking are two types of the wood roof decking. 


The next step in commercial roof construction is adding insulation. It is placed on top of the roof deck as a layer of protection against weather conditions. It will reduce energy costs and regulate internal temperature. Depending on the building’s needs, different types of insulation can be used, such as foam or fibreglass.

Membrane Installation 

On top of the insulation, roofing contractors install the membrane to create a waterproof barrier. Several materials can be used as commercial roofing membranes, including built-up roofing (BUR), single-ply membranes, and modified bitumen. The membrane is stretched over the insulation and attached to the roof deck.


Roof flashing is a thin sheet of metal or material used to cover an opening to prevent water from entering. Typically, flashings are made of metal aluminum or stainless steel and are attached to roof membranes by adhesive or heat welding. Flashing is installed around roof penetrations such as chimneys, vents, and skylights to prevent water from seeping into buildings.

In conclusion, the construction of a commercial roof involves several layers of materials and careful attention to detail to ensure durability and weather resistance. You should consult a qualified roofing contractor to determine the best roofing system for a particular building and location.

Hire Torham Exterior Solution Inc.

If you have any questions regarding commercial roofing, contact Torham Exterior Solution Inc. We are a roofing company that delivers professional roofing services in Hamilton. We do our best to complete roofing projects on time and within budget. Learn more about commercial roofing types in the article How Many Types Of Commercial Roofing, And Which One Is Best?“.