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TPO Roofing Q&A Guide

Find out More About the Most Popular Commercial Roofing Systems

Did you know that nearly 40% of all commercial roofing work done today involves the use of TPO?

These fast-growing roofing systems are highly durable, UV-resistant, and use low-cost single-ply roofing membranes known for their ease of installation. TPO roofing is most commonly used on flat or low-slope roofs.

If you’re thinking of installing this type of roofing membrane, below is a TPO roofing Q&A guide to help you make an informed decision.

What Is TPO Roofing?

Also known as Thermoplastic Polyolefin roofing, TPO is a single-ply roofing membrane that combines polypropylene and ethylene-propylene rubber.

Polypropylene is a chemical compound not only popular for its elasticity and durability but also for its slippery characteristics. This means it can work well to repel moisture from rain or snow. On the other hand, ethylene-propylene rubber is a synthetic elastomer often used for weather and electrical insulation.

TPO material is manufactured in sheets that are available in several sizes. You can best identify a TPO roof by its shiny, reflective appearance.

When Do I Need TPO Roofing?

If you have a roof with a steepness below 2:12 — less than 2 vertical units up for every 12 horizontal units out— it’s considered a flat or low slope roof.

Unlike a higher-pitch roof, water won’t run off as fast on a low-slope roof – necessitating waterproofing. This is why you can’t install asphalt shingles on this type of roof because they aren’t designed to handle sitting water.

Installing a TPO roofing membrane on roofs with a pitch below 2:12 is always recommended. They are more suitable to hold sitting water.

What Makes TPO Roofing Effective?

With so many benefits, it’s no surprise that TPO roofing is so popular today. If you have a low-slope roof, here’s what TPO can do for you:


TPO roofing tends to retain flexibility after installation. It adjusts to your building’s movement as it settles or when it undergoes thermal expansion and contraction. The flexible layer allows it to withstand tears, punctures, and impact damage. TPO is also one of the few 100% recyclable roofing materials available. Unlike other thermoplastic membranes, it’s resistant to dirt accumulation and mold spores.


Compared to other types of single-ply roofing, the costs of TPO roofs are relatively lower. Automated heat welders join the TPO membrane sheets together, helping reduce labor and material costs without affecting quality. This makes it a viable option for both residential and commercial building owners.


TPO roofing comes in a variety of colors – white, grey, tan, and more. Having the ability to choose colors makes it easy to choose a roof design that complements your building’s style.

While all the roof’s colors are reflective and UV-resistant, they provide different levels of protection. Lighter colors offer a higher level of reflectivity compared to dark colors.

Energy Efficiency

TPO’s reflective properties can help keep your building cool in the warm months. This lowers your HVAC bills significantly. What’s more, a wide range of TPO roofs meets the EPA Energy Star requirements.

Class A Fire-Rated

TPO roofs have Class A fire-resistant rating thanks to added fire retardant chemicals during manufacturing. They don’t burn well and are unlikely to contribute to fueling a fire.

Easy Installation

TPO roofing is wider and lighter than most traditional roofing systems. This makes it faster to set up and helps save money on installation labor costs. TPO membrane widths can range from 4-20 feet, in rolls of up to 100 feet long.

How Much Does TPO Roofing Cost?

TPO roofing costs are often valued by “squares.” A square is 100 square feet of roofing material and can range anywhere between $3.50-$14. This means the price of a square of TPO roofing can range from $350 to about $1400.

For TPO installation, a roofer may charge between $75 and $90 per hour. Other factors that may affect the cost of your TPO roofing include the roof condition and size, the choice of membrane used, insulation, the type of warranty, and roof access.

How Can I Install A TPO Roof?

TPO roofing gives you a few options for installation. Below is the typical process professional roofers use to install TPO roofs.

Step 1: Prepare The Roof

Clean and dry the roof before applying any insulation or propylene underlayment. This is because moisture can cause mold damage and degradation over time.

Step 2: Lay Down Insulation

Install the insulation foam on the roof. Cut the insulation to fit around pipes, vents, or other extended structures. Here are a few insulation options that you can choose from:

  • Polyisocyanurate (Polyiso): Costly but has a higher R-value rating
  • Expanded Polystyrene (EPS): Has the highest R-value per dollar and doesn’t hold water over time
  • Extruded Polystyrene (XPS): Typically defined by its pink, blue, or green color, this insulation form is semipermeable with a perm rating of 1

When laying out the foam, stagger it in both directions. This helps give a smoother surface and added strength for better roof insulation.

Step 3: Set TPO

Starting at the edge of the roof next to the wall, roll the TPO membrane over the insulation until you reach the end of the roof. Ensure the TPO doesn’t have any creases or wrinkles. If it does, secure one end of the TPO and pull tight to adjust.

Once the TPO is straight, secure it to the roof surface. Based on your preferences, you can use adhesive, fasteners, or ballast.

Step 4: Heat-Weld The TPO Seams

Heat-weld the seams to successfully join adjacent panels together, creating an impermeable seal. Be sure to also seal up any vent edges on your rooftop.

Should You Apply TPO To Side Walls?

Yes. If you have walls that extend a few feet beyond the roof decking, apply TPO on them to ensure maximum protection for your entire roof.

You will also need resin-based adhesive for this step. Apply it to the walls with a roller before setting your TPO roof coating to create a secure seal. Once you’re done, use a heat welder on the overlapping wall pieces.

How Can TPO Roofing Help Me Save Money?

The most popular TPO membrane on the market is bright white with very reflective properties. As a result, it can reflect UV rays and heat from the building. This will help reduce your energy bills during the warmer months since your HVAC system won’t work as hard to cool your interiors. TPO roofing systems are also well-insulated to keep the warmth in during colder months.

How Long Does TPO Roofing Last?

TPO roofs can last anywhere from 10 to 25 years. Several factors determine how long a roof lasts including how much direct sunlight hits your roof, the weather in your area, quality variations of the TPO membrane, and more. To ensure your TPO roof reaches its maximum life expectancy, prioritize professional roof installation and maintenance.

How Do I Maintain A TPO Roof?

Structural movement, mold and algae growth, harsh weather, and reactive maintenance can wear out your flat roof over time. Staying on top of your maintenance can help protect your investment. Some maintenance tips to ensure your TPO roof lasts longer include:

  • Address small tears, cracks, and holes as soon as you notice them
  • Thorough annual or biannual roof inspections
  • A comprehensive roof maintenance strategy from a qualified roofer With scheduled maintenance, you can save money on constant repair costs and take care of any safety hazards before it's too late.

What Happens If There’s A Tear In My TPO Roof?

Noticed a tear on your TPO roof? This might happen as a result of the following:

  • Flying debris in storms
  • Prolonged exposure to UV rays
  • Rodents chewing on the membrane
  • Hail damage

Once a tear happens, it exposes your roof’s insulation. If left unchecked, the tear can expand and allow water to penetrate and spread into the roof deck. This can cause leaks and compromise your building’s structural integrity.

What Are The Repair Options For A TPO Roof?

TPO repair methods will depend on the severity of the damage. Some of the best TPO roof repair options include:

Add A Secondary Coating

Patch any areas that show signs of damage using waterproofing coatings like professional-grade PVC material. It will help protect the insulation and roof deck from further moisture damage. Before applying the coating, check to see if it needs a TPO primer to adhere properly.

Cover The TPO Roof With Elastic Cement

Use high-quality and flexible elastic cement to seal and waterproof the tears. This is a suitable repair option when dealing with failing seams around flashings and joints. Elastic cement is not only long-lasting but also compatible with most products.

Roof Replacement

Is your TPO roof severely damaged? You may need to remove the damaged portion and replace it. A professional roofer should be able to evaluate the state of your TPO roof and take the necessary steps to fix it.

How Does TPO Compare To Other Single-Ply Membranes?

There are 3 main types of single-ply membrane roofs — TPO, EPDM, and PVC. Let's see how TPO compares to EPDM and PVC.


EPDM roofing is made from a type of rubber known as ethylene propylene diene monomer. While EPDM roofing systems are durable, they’re prone to shrinkage over time.

What’s more, their adhesively bonded seams are not as sturdy as those of TPO roofing. TPO's seams are 3-4 times tougher than EPDM's.

Also, EPDM is black and lacks reflective properties, unlike TPO. This makes it unsuitable for warmer climates as it increases the heat load put on your roof surfaces. From a cost standpoint, EPDM is slightly more expensive than TPO.


PVC stands for polyvinyl chloride. Similar to TPO, it is a bright, heat-welded, and thermoplastic single-ply roofing material. TPO and PVC are also both easy to install and very reflective.

However, unlike TPO, PVC holds up better to intense heat. It also has greater resistance to oils, fumes, grease, and other chemical substances. But PVC is generally way more expensive compared to TPO.

Consult Qualified Local TPO Roofing Contractors

Installing a TPO roof is a big investment. To enjoy value for money, you need professional and experienced TPO roofers near you.

This is where Mighty Dog Roofing comes in. We can help you visualize your roof beforehand so that you’re confident in your decision. Roofing financing is also available.

If you have any more questions about TPO roofing, our roofing professionals are always happy to answer. Contact us today to learn more.