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A Guide to Commercial Roofing

a flat roof on a commercial building

If you're new to commercial roofing, also known as a flat roof, it might be a little overwhelming choosing the right system. Some systems are less expensive than others. Some last longer than others. Some are better in certain situations than others.

So, how do you choose?

This guide gives you a brief overview of the various commercial roofing systems, the advantages and disadvantages of each, the life expectancy of each, and the average cost to install and repair each one.

Below you'll find answers to the following questions:

What is a commercial roof, also know as a flat roof?
How is a commercial roof different from a residential roof?
Why have a flat roof?
How much does a commercial roof cost?
What are the commercial roof material types?
The life expectancy of the various commercial roof material types.
How much does each commercial roofing product weigh?
What are the pros and cons of PVC, TPO and EPDM?
Which flat roof system is best?

What is a commercial roof?

A commercial roof, also known as a flat roof, is not just a roof for a commercial building. Commercial roofs are often differentiated from residential roofs due to the fact that they have to perform different functions. For example, a commercial roof not only has to protect a building from the weather, but also often support heavy equipment such as large air conditioning units. For this reason, commercial roofs are often made differently and use different materials.

Flat roof

Contrary to the name, a flat roof is not actually flat. Flat roofs are called flat because they are significantly less sloped than traditional residential roofs. In other words, they just look flat. If you place a really long level on a flat roof, you'll see that the angle is 10º or less. By comparison, most common roof pitch angles for houses is between 18º and 36º.

3 key points how a commercial roof is different from a residential roof:

1. Size
Commercial roofs are often significantly larger than residential roofs and creating a highly sloped roof for a large commercial building is impractical from a construction standpoint.

2. Heavy
Flat roofs often have to support heavy equipment such as large air conditioning units. It's much easier to install an air conditioning unit on a flat roof than a highly sloped roof.

3. Flat
Commercial buildings are often constructed with flat roofs instead of highly sloped roofs because flat roofs are cheaper to build.

Why have a flat roof?

1. As mentioned above, flat roof frameworks and decks are less expensive to build compared to traditional residential high-sloped roof frameworks.

2. If you want your building to have a lower profile. Maybe there's a height limitation in your city or you need your commercial building to stay below power lines.

3. If you need your building to have a lower slope, for example, if you need to install heavy equipment on it.

Who uses a flat roof?

Most of the time, commercial building owners use a flat roof. However, it is not uncommon to have a flat roof on non-commercial buildings. We have installed flat roofs on new garages and home additions.

How much does it cost to install or replace a flat commercial roof?

chart comparing prices of commercial roofing material types

The cost to install a commercial roof depends upon the insulation and recovery board underneath the membrane.

The cost to replace a commercial roof also depends upon the condition of the existing roof, if the existing insulation and recovery board needs to be replaced, among other things. So, for our price comparison, let's leave all that aside.

Let's assume you have a 2500 square foot commercial building with a flat roof.

To install just the membrane for a commercial roof, here are some averages:

EPDM: $5.50/sf ($15,000)

TPO: $7.00/sf ($16,000)

PVC: $8.50/sf ($20,000)

What are the commercial roofing material types?

There are several commercial roofing material types available today. However, here are the ones we offer:

  1. PVC (polyvinyl chloride)
  2. TPO (thermoplastic polyolefin)
  3. EPDM (ethylene propylene diene monomer). Also known as a rubber roof.

We are proud to install flat roof systems from the industry’s best brands:

What is PVC roofing?

PVC stands for polyvinyl chloride. It is a flexible thermoplastic membrane with excellent weathering properties. Read more about PVC roofing.

What is the life expectancy of a PVC, TPO or EPDM roof?

chart showing commercial roofing material life expectancies

A PVC roof can last 20 years or more when installed correctly using today's modern technology. TPO, 25 years. EPDM, 30 years.

When a commercial roof fails, it is often because it wasn't installed properly. When properly installed, the seems are actually stronger than the membrane itself.

How much does PVC, TPO and EPDM weigh?

Per square foot, for 60 mil, membrane only, fully-adhered:

EPDM: .5lbs.

PVC: ~.4lbs.

TPO: .3lbs.

What are the pros of a PVC roof?

Fire-resistant
PVC is an inherently fire resistant polymer.

Strong
Flat roofs using PVC are specifically engineered to be strong; 300+ pounds per square inch of breaking strength.

Durable
PVC seems are stronger than the membrane itself.

Energy efficient
Vinyl roofs are energy efficient due to their light color.

Resistant to grease
PVC is highly resistant to kitchen greases and animal fats.

What are the cons of a PVC roof?

The only disadvantage, and it really isn't a disadvantage, of PVC roofing is the cost. Not that it's that expensive, but of the 3 single membrane flat roofing materials, it is generally considered the more expensive one.

What is TPO roofing?

TPO stands for thermoplastic polyolefin. It is the most affordable of the commercial roofing options. It is a reflective roofing membrane made from polyprophylene and ethylene-propylene rubber polymerized together. Read more about TPO roofing.

What are the pros of a TPO roof?

Affordable yet durable
A TPO roof offers the best of both worlds; the low cost of EPDM with durable seems like PVC.

Resistant
TPO is resistant to dirt, bacteria, algae.

Flexible
Because TPO is flexible, it is resistant to tears, punctures and impacts.

Strong
TPO has fabric embedded within the membrane for strength.

Reflective
Because TPO is naturally white, it's reflects light reducing your utility bill.

What are the cons of a TPO roof?

The only disadvantage of a TPO roof is that it's still a relatively new product. Not all TPO roofs are created equal. Some TPO manufacturers are better than others. After extensive research, we've found that Mule Hide, Versigo and Genflex make a great TPO roofing material.

What is EPDM roofing?

EPDM stands for ethylene propylene diene monomer. EPDM is also known in the industry as a rubber roof. It is an extremely durable synthetic rubber roofing membrane most commonly used on low-slope commercial buildings. Learn more about EPDM roofing.

What are the pros of an EPDM roof?

Cost
People choose EPDM because it's the most affordable of the flat roof membranes. EPDM is not only the least expensive flat roofing material to purchase, it is also the least expensive to install and repair.

Longevity
Of the 3 flat roof materials we offer, EPDM is the longest lasting at 30 years on average.

Strength
EPDM has a high tensile-strength.

Lightweight
Because it's basically rubber, EPDM is lightweight and doesn't require additional roof deck support.

Flexible
EPDM remains flexible when either hot or cold so it won't crack or split when expanding or contracting.

Puncture resistant
Our vendors make a superior EPDM product that is resistant to punctures.

Recyclable
Although no one in our area (Colorado Front Range) recycles EPDM material, it is made from recycled rubber and at the end of your EPDM roof's cycle, it can be recycled again. Check your area for recycling centers.

What are the cons of a EPDM roof?

Can puncture fairly easily
Although EPDM is puncture resistant, it is not puncture proof.

Appearance
At the end of the day, it's rubber. It's either black or white. Nothing exciting. Ballasted (rocks) are an improvement.

Poor petroleum resistance
EPDM has a poor resistance to petroleum-based products.

So, which flat roof system is best?

Which flat roof system is best depends upon your needs and your budget.

Most like TPO because it's white and reflects heat. Even more, TPO has fabric embedded within the membrane for added strength.

PVC is good for restaurants because it's resistant to greases and animal fats.

EPDM is cheaper than TPO which is good for savings.

Choose PVC if you own a restaurant as it's resistant to grease and animal fats.

If you want lower utility bills, again choose PVC as it's the most reflective.

Because it's fire resistant, PVC wins, again.

If cost is the determining factor, choose either TPO or EPDM.

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