What is the most common type of roof for commercial buildings?

About Commercial Roofs

There is a lot of responsibility in owning a commercial property. Making the electricity and plumbing are in working order, the security system is in working order and keeping the structure in good condition. That includes choosing the right material for commercial roof installation that holds up to the climate in Pittsburgh, Pennsylvania. Most commercial roofing is low-sloped or flat, and where architecture is concerned, some may have a steep design, like a church.

What is a flat commercial roof made of?

Flat Roof commercial roofing installation can be made from one of several materials. The following are typically made of the following 5 most popular: 

  • Built-Up Membrane
  • Metal
  • Modified Bitumen
  • Thermoset 
  • Thermoplastic

What is the best commercial roofing material?

Commercial roofs either have a low slope roof or a steep slope roof, which is a vital part of the entire building’s aesthetics and overall health. So, when it is time for a new commercial roof installation, there are 5 types of materials to choose from:


BUR as it is referred to in the industry, is the standard tar & gravel roofing. The name ‘built-up roofing’ comes from the multiple layers used to install this type of roofing.  This creates a flexible roofing material budget-wise because the number of layers can be modified to stay within the budget. It is one of the most durable and toughest materials for commercial roof installation.


One of the most popular choices for commercial roof installation

 is metal, which has several variations that include:

  • Aluminum
  • Aggregates of aluminum, silicon-coated steel, and steel
  • Copper
  • Corrugated galvanized steel
  • Lead
  • Metal tile sheets
  • Stainless steel
  • Stone-coated steel
  • Tin

To protect against the harsh UV rays and other environmental issues, protective surface layers are added. This gives a finished aesthetic appearance and durability, with a high fire resistance rating, and is a sustainable material. 


This material for commercial roof installation uses reinforced roof fabrics that are “carriers” for bitumen. It is cut and installed in a BUR method, layers that are fastened to the commercial rooftop in a two-ply system. It is adhered to the decking, providing maximum protection and stability.


The industry refers to this as EPDM, ethylene propylene diene terpolymer, which is a durable and long-lasting commercial roof installation material. Easy to maintain and repair makes it a number one choice for many commercial property owners.  Provides a strong resistance to ozone and UV light, this single-ply rubber material helps keep energy costs lowered and is ideal for the cold temperatures in Pennsylvania. 


TPO (thermoplastic polyolefin) and PVC (polyvinyl chloride) are lightweight materials for commercial roof installation are highly reflective and have excellent weather resistance, UV resistant, bacteria resistance, and UV light. Durable and withstands punctures or tears, and has a strong resistance to most chemicals, making it ideal for restaurants or any industry that has fats and oils emitted from the ventilation system. A high tolerance to fire, wind, and high temperatures.

When should a commercial roof be replaced?

Like household appliances, commercial roof installation is recommended when the cost to repair is more than fifty percent of new roofing.  Because by that point of aging and integration, the existing roof is no longer performing cost-effectively. Typically, at this point, the seams are worn, and the material itself is worn and blistering. 

flat roof covering works with roofing felt

How long does a commercial metal roof last?

Commercial roof life expectancy varies depending on the material used, all of which can range between 10 years and 50 years. 

  • TPO roofing system: 22 to 30 years
  • EPDM roofing system: 22 to 35 years
  • Metal roofing system: 30 to 45 years

How long does it take to roof a commercial building?

Generally, a commercial roof installation can take between two and four weeks. The size of the structure and the roofing material will determine this, and during the estimate, the roofing contractor will provide a more accurate time frame. 

How long does it take to replace a commercial roof?

A commercial roof installation typically takes between 5 days and 4 weeks. There are several factors that can affect this timeline: 

  • Type of Roofing Material
  • Material Availability
  • Scope of the Project
  • Permit Revisions
  • Weather
  • Inspections

How do you repair a commercial roof?

The commercial roof repair process will depend on the problem and the existing roofing material. The first step a roofing contractor will take is to check the flashing and repair or replace it as needed. 

Any area that has worn-out sealant is re-caulked or re-tarred to give the commercial roof installation a secure and tight seal. 

If there is any damaged plywood on the roof decking will be replaced. The felt sheeting is replaced, then glued or stapled, and caulking is applied over the staples to ensure they are watertight. 

The Bottom Line – The Main Question

Every commercial structure owner will be concerned with the financial part of this project. How much does it cost to replace a commercial roof? This isn’t a number that can be stated and held to be accurate and true because it will depend on the size of the structure, the type of material used, and the cost of goods and labor is ever-changing. On average, the cost can start at $5,000 and go upward from there.

Great Lakes Commercial Roofing provides assistance with commercial roof installation in Pittsburgh, PA. Call us at 412-256-8050 for services.

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