TPO Roofing Guide

TPO Roofing Guide

Is TPO Roofing the Right Choice for Your Business? A Comprehensive Guide

A rising number of building owners are choosing TPO roofing systems for their industrial and commercial buildings because it is cost-effective, long-lasting, and also resistant to UV rays. They are also easy to install and they deliver a beautiful white and professional appearance after installation.

Despite its many advantages, several considerations must be made before choosing to install TPO roofing. You need to be aware of the cost, limitations, durability, installation and repairs, as well as restoration of TPO using elastomeric roof coatings.

What Is TPO Roofing?

TPO, which stands for Thermoplastic Polyolefin membrane is a roofing material that has several synthetic polymers and a fabric scrim for reinforcement, delivering great performance and strength to the roof.

TPO can be described as one of the newest roofing options for commercial buildings because it has only been around since the early 1990s. It is most commonly found on flat roofs with low slopes, both in residential and industrial areas.

TPO belongs to the single-ply roofing membrane category because it is installed in a single layer. You can fasten TPO to your roof substrates mechanically or with the aid of chemicals. The seams are designed in a way that they ought to be welded together using heat.

TPO membranes come in rolls and they have varying widths, spanning from 4 to 6, as well as 10 to 12 feet. TPO membranes come in thickness options of 45mils, 60mils, and 90mils. Thicker membranes are often preferred because they last longer than lighter ones.

As for colors, you can find TPOs in white, black, gray, and tan, as well as other uncommon colors. However, white is often the most popular color. The alternative colors offer better UV protection but they’re not as reflective as the brighter ones.

Some of the most popular TPO manufacturers are Johns Manville, GAF, Carlisle-Syntec, and Firestone, but new names are entering the industry every day.

Advantages of Choosing TPO Roofing

There are so many pros associated with TPO roofing, and they include:

  1. Energy Efficiency

TPO roofs are cost-effective because of their reflective and UV-resistant nature. When you use TPO roofs, the surface temperature is lower, and it, in turn, reduces the cost of cooling your home in Summer.

  1. Cost-Effective

TPO is more affordable than many commercial roofing materials, which is the reason many commercial building owners prefer it.

  1. Ease of Installation

Due to the lightweight nature of TPO, it is easier to maneuver it on the roof, and this makes the work easier and faster for the installer, thereby reducing installation costs.

Also, TPO membranes come in wider sheets, thereby reducing the number of seams to be welded.

  1. Durability and Flexibility

TPO is very durable because it is designed to hold its own against extreme weather and UV rays. It also has a good amount of resistance against water and impact damage, punctures, as well as buildup of dirt.

Disadvantages of TPO Roofing

Despite the pros of installing TPO roofing membranes, there are also some disadvantages to be aware of, including:

  1. Quality and Longevity Issues

The lifespan of TPO roofing systems is quite debatable and can be anywhere from 10 to 25 years. Because they are new in the industry, it is hard to vouch for the manufacturing process of TPO, membranes, meaning some people might be unlucky enough to purchase poor-quality membranes that won’t last as long as expected.

  1. Heat Damage

When your TPO membranes are exposed to extreme heat, the flashings and seams begin to separate and the material begins to crack. You might also find that the laminated top layer deteriorates fast, leaving the membrane prone to damage.

The Installation Process of TPO Roofing

There are several processes entailed in the installation of TPO roofing, and installing TPO on the average commercial roof of 20,000 sq. ft. often takes 1 to 2 weeks. It could even take longer if the installation process requires the substrate and insulation on the roof to be removed and replaced.

Several factors might also affect how long it takes to install TPO, including the size, complexity, weather, and chosen installation method.

  1. Step 1: Insulation

The first step is to add insulation to the roof surface to ensure that the roofing system has better thermal resistance, also called R-value, which refers to how much heat flows through a given material.

Most of the roofing insulation you’ll find comes in large rigid boards that get joined to the substrates or roof decks or substrates using chemicals or mechanically. The boards are installed throughout the roof surface following a parallel pattern with tight joints, then some areas are tapered for proper roof drainage.

There are several insulation methods, and for some purposes, more than one insulation layer is used, especially when it is needed for some specific energy ratings.

  • Expanded Polystyrene (EPS)

This method is used across several building constructions, including ceilings, floors, walls, and facades. This method has very high R-values compared to other foam insulation boards.

  • Polyisocyanurate(Polyiso)

This is the most common insulation type for commercial roofing applications. It is more expensive than other insulation boards, but its R-value per inch is way higher than other boards.

  • Extruded Polystyrene (XPS)

This board has unique colors, including green, blue, and pink. It is more lightweight and dense compared to others, and it is also made of semi-permeable foam material that has great water resistance.

  1. STEP 2: Cover Board

Depending on the nature of the insulation being used for the project a cover board will be installed after the insulation layer has been installed, and before the TPO membrane will be installed.

A cover board is a thin substrate that roofing membranes will be adhered to. Despite its thin nature, it is durable and it serves as protection for the insulation against damage from wind, hail, and fire.

Alternatively, you can apply TPO to polyiso insulation directly without installing the cover board. However, when using XPS and EPS insulation, the manufacturer installs that a cover board has been installed.

  1. STEP 3: TPO Membrane

The final step is when the TPO membrane is installed onto the cover board or substrate, and there are two popular ways to do this. It can be mechanically fastened using plates and screws or adhered using a bonding However, there are some other methods to attach TPO membranes. A heat gun and a seam welding machine can be used to install the TPO membrane by welding all the accessories and seams together using heat until they become a single, large, watertight roofing system.

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How Much Do TPO Roofs Cost?

The cost of TPO roofs will depend on several factors, such as the size of your roof, the nature of the current insulation and whether or not a new one is needed, the chosen TPO thickness, as well as the choice of insulation and installation method.

However, on average, TPO roofing systems cost between $3.00 and $9.00 per square foot.

Bear in mind that you might find some TPO materials from other manufacturers that are way cheaper, but it might not be a great idea to buy them, especially if their manufacturers aren’t notable. This is because they will most likely be of very poor quality.

How does the cost of TPO compare to other roofing materials?

On average, TPO has a low-end cost of $3 and a high-end cost of $9 per square foot, EPDM ranges from $4 to $10. PVC costs between $5 and $12, Metal is between $3 and $15, and SPF ranges between $5 and $8. Built-Up roofing material ranges between $6 and $14, while Modified Bitumen costs $5 to $12 for low-end to high-end roofing materials.

Bear in mind that the commercial roofing system cost can also change depending on the type of panel profile.

What is the Lifespan of TPO Roofs?

The lifespan of TPO membranes continues to be an issue of debate. However, they last between 10 and 25 years.

It is believed that thicker TPO materials last longer than the slimmer version, and this is why they often buy the thicker version. However, this isn’t a fact because longevity is dependent on manufacturing quality and not thickness.

Also, because TPO is quite new in the industry, it is hard to tell where it stands when compared to other flat roofing materials.

TPO technology takes some getting used to, and there have been new developments in TPO technologies, including several new manufacturers.

How Does TPO Compare to Other Single-Ply Membranes?

We will be comparing TPO to two very popular single-ply membranes, which are PVC and EPDM.

Comparing TPO and EPDM

Ethylene Propylene Diene Terpolymer, popularly known by its abbreviation, EPDM, is a rival membrane that is as popular as TPO and has the highest market share compared to other single-ply membranes.

EPDM is very flexible and durable and made of synthetic rubber compounds. It comes in rolls of different widths and thickness ranges, just like TPO.

EPDM scores higher than TPO in terms of longevity because its lifespan is estimated at 30 years or more.

A major difference between EPDM and TPO is their color. Although most EPDM materials come in black, they also have colors like gray, white, and tan. However, the popular Black EPDM membranes don’t reflect as much as the white TPO counterparts, making TPO better for warmer climates than EPDM.

On the other hand, EPDM roofing systems are preferred over TPO across most northern regions because of their ability to retain more heat than TPO in Winter.

When it comes to cost, EPDM is a bit more expensive than TPO, but it isn’t a problem because EPDM roofing systems are believed to deliver more value as they have a longer lifespan than TPO.

However, EPDM roofing systems will most likely shrink over time just as their seams which are bonded using adhesives aren’t as strong as the seams of TPO roofing systems.

Comparing TPO and PVC

PVC, which is an abbreviation for polyvinyl chloride is a popular single-ply membrane that’s commonly called an original weldable sheet.

PVC is similar to TPO because they are both thermoplastic, are both welded using heat and are both bright-white single-ply materials. Their similar appearances make it hard for some people to tell them apart. They are both reflective and can be installed easily.

The lifespan of PVC materials is about 20 years plus, and it is very flexible, UV and weather resistant. The most common colors of PVC materials are gray and tan.

One difference between TPO and PVC is that PVC resists intense heat better than TPO and also has better resistance to oils, grease, fumes, and several chemicals, making them the more sought-after single-ply roofs in the food service industry.

PVC also has a better quality reputation than TPO because it has been in the market for longer and its reputation in the commercial roofing industry has been tried and true. You won’t hear about low-quality variations of PVC materials in the market.

However, one major disadvantage of PVC is that it is costlier than TPO and other single-ply membranes. It also tends to shrink with age and can crack in colder weather. Also, the National Roofing Contractors Association (NRCA) prohibit foot traffic on PVC roofs when external temperatures are less than 50°F.

How to Maintain and Repair TPO Roof 

Despite its longevity and effectiveness, TPO needs regular maintenance and repairs to perform optimally. When you carry out routine maintenance on your TPO roof, you can ensure longevity and avoid common problems that can shorten the lifespan of your roof.

Roof maintenance is a simple process that involves identifying little problems and repairing them to avoid worsening situations.

Common Problems of TPO Roofs 

Most TPO roofs first face problems with the flashings and seams and this is connected to the roof’s thermal movement in response to fluctuating internal and external temperatures. The continuous movement will pull at the flashings and seams, leaving tiny openings that allow water to enter the roof.

Other problems include improper installation and excessive heat loads. Also, due to its single-layer nature, TPO is prone to sudden damage by debris carried by the wind, hail, addition of equipment additions, and even damage during transportation.

If you don’t maintain your TPO roofing system often, you’re setting it up for complete failure.

Purpose of TPO Inspection 

Routine inspections are necessary to spot and fix roofing issues. These roof surveys ought to be carried out on TPO roofs in the Spring and Fall of every year. It is also necessary to carry out roof inspections after a period of severe weather, such as heavy wind, rains, and hailstorms.

TPO roofing inspection is aimed to observe the following:

  • Whether or not the flashings and seams are in good condition
  • Signs of leaks and the sources
  • Roof decking condition
  • TPO membrane age
  • Insulation layer saturation levels

TPO Roof Repairs 

Once the problems have been identified, the next step is to immediately repair the roofs to avoid costlier repairs. Several materials and tools are used to repair TPO systems, and a certified TPO roofing expert should carry out the installation.

Visible and simple damages like splits, tears, and small punctures should be repaired quickly using industrial-grade roofing sealant, which is a temporary fix until the implementation of a permanent solution, which is a roof patch.

A roof patch entails the application of tiny pieces of TPO materials to the damaged areas for long-lasting repairs. These repairs are considered to be the standard, and you find many commercial roofers offering warranties for these roofing repairs.

For more severe damage to your TPO roof, the roofing repairer will need to take more extensive measures, and this is where it becomes necessary to consider different roofing options, depending on how much saturation exists within the insulation.

Options for Roof Repairs

  1. Restoration

For negligible saturation levels, a roof coating or restoration system is the best option to choose.

  1. Re-Covering 

Re-covering, also known as re-roofing, or implementing a layover entails adding a new TPO roofing system over the existing membrane without removing it. This is the best option if saturation issues are at the minimum, but won’t be a good option for higher saturation levels.

  1. Replacement 

In a situation where the roof is too saturated, it becomes necessary to completely tear off the roof and replace the TPO insulation and membrane.

Spray Foam Roofing (SPF) as an Alternative to TPO Roofs

One great alternative to TPO roofs is SPF, which stands for Spray polyurethane foam. It is energy-efficient and highly durable and has the highest thermal resistance (R-value) compared to other roofing materials.

You can apply SPF systems in liquid form onto roof substrates. When the foam cures, it gets stronger, and the result is a thick, but lightweight insulation membrane. The next step is to coat the foam layer with elastomeric roof coating to offer UV protection.

SPF is classified as a replacement and a re-cover option because you can either install it over TPO membranes or use them to replace the TPO membranes. They can also be recoated several times over a 10 to 15-year period.

TPO Restoration with Roof Coatings

When your TPO membranes aged, you can carry out restoration coating on them. The aging process of TPO roofs delivers a semi-textured finish that is great for coating adhesion.

On the other hand, when your TPO roof is still new, it is shiny and slick, and it’s not easy to stick coatings on it.

So, your TPO membrane needs to be between 3 and 5 years old for roof restoration systems to perform properly. Depending on the situation, an etching rinse or a primer might be necessary to ensure proper adhesion.

Advantages of Roof Restoration

Roof restoration using roof coating systems delivers a watertight and seamless membrane that stops leaks, saves energy costs, and extends your roof’s lifespan while boosting sustainability. Roof restoration is also very much affordable compared to other roof replacement and tear-off methods, and the installation process is easier and faster. You can also get different ranges of warranties from roof coating manufacturers.

When is it Ideal to Restore TPO Roofs?

It is advised that you restore your TPO roof before roofing issues such as leaks spread through the roof. Seeing as commercial roofs are constantly exposed to the sun and other elements, it is important to restore your roof before issues occur.

You’ll need to ensure that the roofing assembly is structurally sound and the insulation isn’t saturated. The current membrane should also be the right age for roof coating.

What is The Best Roof Coating for TPO?

The best roof coating options for low and flat-slope TPO roofs are solvent-based coatings like urethanes and silicones because they are highly resistant to gathering water.

Although acrylic coatings are more affordable, it isn’t advisable to use them on TPO and other flat roofs. This is because acrylics are water-based and ponding water will spoil them.

Available TPO Roof Coating Systems 

  • Envir-O-Sil Coating

The Envir-O-Sil Coating System comprises low VOC and high-solid silicone coatings. It is the best eco-friendly roof coating solution for areas that have strict environmental regulations.

  • Ure-A-Sil Coating

The Ure-A-Sil Coating System is s combination of the strength and adhesive nature of urethane coatings alongside the UV-resistant and waterproofing nature of silicone coatings.


There are so many advantages of TPO roofing, and if you install, maintain, and repair them properly, they will last longer and continue to deliver great energy efficiency and UV protection to your commercial building.

To learn more about TPO roofing systems, and whether or not they are a great option for your commercial building, reach out to us to get advice and a free estimate.

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