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Commercial Roofing Types: Advantages and Disadvantages They Provide

Article Posted On: March 23rd, 2018 | Last updated on: January 31st, 2019 at 9:20 am | Written By: Sentry Roofing
Commercial Flat Roof Installation

There are advantages and disadvantages to every type of commercial roofing system. This article will give you an overview of the most widely used types of roofs so that you can make more informed decisions on your commercial roofing types.

Sentry Roofing installs and repairs flat roofs, low-slope roofs, metal retrofit roofs and membrane roofs. The brands we use are Duro-Last, Firestone and GAF

Below is an examination of these commercial roofing types, the materials, and the advantages and disadvantages of each type of roof.

Types of Roofs: Pros and Cons

Commercial Roofing Contractors Indiana

Commercial Flat Roofs: Pros and Cons

Flat roofs are one of the most common types of roof for commercial buildings.


Flat roofs can be significantly more cost effective to build than pitched roofs or steep slope roofs because they require less material due to the fewer square feet to be covered. They are easier and quicker to install, which can translate to a significant savings for the building owner.

Owners have many types of flat roofing materials to choose from – rubber rolled roofing, EPDM, TPO, bitumen and modified bitumen.

Air conditioners can be moved from the ground to the roof. Solar panels and satellite dishes are easier to install on flat roofs than on pitched ones. These items are then less obvious from the curb or parking lot.

Maintenance and drain cleaning is easier on flat roofs since workmen can walk easily and safely, regardless of weather conditions.


Disadvantages of flat roofs can include standing water problems. It is imperative that an experienced commercial roofing contractor with a good reputation for professional work do the installation or repairs in order to avoid problems with the roof.

The most important issue is poor drainage. An experienced commercial roofer will understand where the drains must be located and the proper height to avoid puddling. Standing water can degrade the roofing materials long before they normally would. One of the advantages of pitched roof styled buildings is not having to worry as much about drainage issues. Materials breakdown leads to leaking and water damage inside the building.

The length of the warranty period on the type of materials that can be used to cover a commercial flat room can be a concern. Sentry Roofing, a commercial roofer in Indiana, uses rubber rolled roofing, EPDM, TPO and bitumen. These are good materials for commercial roofs but have a warranty period of about 10 to 15 years. The warranty period can be extended considerably by using modified bitumen as the top layer of the roof.

Duro-Last Slow Slope Roof Installation Membrane Williamsport, Indiana

Commercial Low-Sloped Roofs: Pros and Cons

Low-sloped roofs are often found on factories, warehouses, apartment buildings and other industrial buildings. They may first appear to be flat but they actually have a slight pitch.


The pitch of low-sloped roofs allows for water runoff. The roof design directs the water to where it should go, such as valleys, saddles and drains. Roof area is less than with high-pitched roofs, requiring fewer square footage of roofing materials.

Low-sloped roofs offer easier and safer conditions for roofers to work on than high-pitched roofs or steep slope roofs. Roof installation, repair and replacement is easier to perform. There is less chance that the building owner will need to call repairmen out to manage water problems, since the slight pitch does not allow for standing water or puddling.

Air conditioners, solar panels and satellite dishes are easier to install and maintain on low-sloped commercial roofs than on roofs with a higher pitch.

The same variety of materials that are used on commercial flat roofs can be used on low-sloped roofs – rubber rolled roofing, EPDM, TPO, bitumen and modified bitumen. Modified bitumen have longer warranty times due to the additional thickness and superior sealing capabilities.


* Heavy snows that do not melt quickly can add weight to the roof. Building codes regarding low-sloped roof for your area must be adhered to precisely.

Duro-Last Metal Retrofit Roof Overview Danville, IL Cross Roads Christian Church

Commercial Metal Retrofit Roofing: Pros and Cons

Metal retrofit roofing is a simple, cost-effective method of re-roofing your older, end-of-life metal roof with a durable membrane.


The biggest advantage is the cost of the retrofitting your metal roof. This material not only greatly extends the life of your roof, it doesn’t cost as much as your standard metal roof replacement.

During installation, the original metal roof provides  protection to your building’s interior so you can continue day-to-day operations while the work is being done. This protects your employees, your inventory, and doesn’t interrupt production.

Retrofitting is also eco-friendly. By not taking the roof apart and damaging / scrapping the materials, this reduces landfill waste, making re-roofing an appealing option for the environmentally-conscious.

When you retrofit over a metal roof, you are taking advantage of reusing your current roof insulation, as well as additional insulation from the membrane. This can help save on energy costs and keep building temperature regulated. 


While having a metal retrofit roof installed over your existing metal roof can extend the life of your roof by up to 20 years, a complete metal roof installation is generally estimated to last between 30 – 60 years.

Keep in mind this comes at a significant cost increase and can be more cost-effective to simply retrofit.

Read more about metal retrofit roofing systems here.

Membrane Roofing Systems Indiana

Commercial Membrane Roofing: Pros and Cons

This type of roofing has become very popular for flat and low-sloping commercial roofs. It is made of thermoplastic/PVC, synthetic plastic, bitumen or modified bitumen. The two basic types of membranes are TPO (thermoplastic polyolefin) and EPDM (ethylene propylene diene terpolymer).


The membrane is slick and good for moving water off the roof. Its light weight property puts less stress on the building structure than does metal roofing. The flexibility of membrane roofing materials allows commercial roofing contractors to mold the material to unique roof designs.

TPO membrane’s light color is good for reflecting heat away from the building. TPO membrane comes in white, tan, gray, green, red and blue. This material uses a hot-air gun to seal the seams.

EPDM roofing membrane has been on the market for over 60 years and has a good track record as a commercial roofing material. EPDM is a darker color, which is good for cooler climates. Its highly durable rubber provides excellent protection from the weather. Seams are closed with adhesives or seam tape.

Since the membrane does not have its own insulation, the building owner has several insulation options to choose from.


Foot traffic on a membrane roof can lead to punctures. Loose nails or screws on top of the membrane can be stepped on by workers, causing a puncture.

Hot weather can cause the membrane to shrink, causing tear which lead to water getting under the membrane. Adhesives and seam tape can degrade from UV sunlight, allowing water to flow under the membrane.

TPO has not been on the market as long as EPDM, so less data has been accumulated about its longevity.

In spite of these disadvantages, commercial membrane roofs are very popular and should be considered as a roofing option.

With such a variety to choose from, the best course of action in the Indiana area is to call Sentry Roofing and talk to a professional commercial roofing contractor. Sentry has the experience to recommend the best type of roof for your particular building. In addition, they know the different brands of materials – Firestone, Duro-Last and GAF – and will explain the advantages of each of them to you.

Read more about membrane roofing systems here.

Commercial Roof Types:

  • Flat Roofs – More cost effective, quicker and easier to install. Materials include rubber rolls, EPDM, TPO, bitumen, and modified bitumen. However flat roofs are more prone to standing water and material degradation.
  • Low Sloped Roofs – Allows for better water runoff which means less maintenance calls. Safer and cheaper than pitched roofs and can use the same materials. Heavy snows can weigh down and potentially cause damage.
  • Metal Retrofit Roofs – Simple, cost-effective method of re-roofing a metal roof with a membrane system. Reuses your current roof structure and insulation making it environmentally friendly and structurally sound. Can greatly extend the life of a damaged roof. 
  • TPO Membrane Roofs – Light color, good for reflecting heat away from the building. Colors come in white, tan, gray, green, red, and blue. Seams are sealed with hot-air gun. However, easier to puncture and prone to shrinkage.
  • EPDM Membrane Roofs – Darker roofs, better suited for cooler climates. Made of a highly durable rubber providing protection from the weather. Seams are sealed with adhesives / seam tape. Also prone to holes and shrinkage.

Protect your facility, business, staff and clients with a contractor team you can trust!