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TPO Roofing – What You Should Know

TPO roofing is fast becoming the gold standard for commercial facilities, but why? And what even is it? Today we’re going in-depth into this innovative new style of roofing, and why it might be the perfect match for your flat roof or low slope roof.

Our experienced and professional roofers have the equipment, expertise, and experience to get your commercial roofing installation done on time and on budget. We know that you need the best possible experience, particularly for a large commercial project, and are committed to helping you have the best experience possible.

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Why TPO roofing is so popular

If you’re not sure if you’ve seen TPO roofing in action, it’s the bright white roof style common on many modern flat or low-slope roofs for commercial facilities. It’s become something of a hot choice in single-ply membrane commercial roofing, primarily because of the excellent energy savings it offers.

In San Francisco, it has become an incredibly popular commercial roofing system, as single ply roofing can be retrofitted to older buildings relatively easily and is widely seen as one of the most cost-effective solar roofing systems. Energy-efficient roofing material is becoming a big draw card, especially in commercial roofing.

What is a single-ply membrane?

Single-ply membrane means the roof uses synthetic or rubber sheets as a layer of protection. They’re either mechanically fastened into place, adhered chemically, or ballasted into place. TPO roofing is the most common form of single-ply roofing currently on the market, although there is notable others.

TPO roofing, or Thermoplastic Polyolefin, is incredibly popular. EPDM (Ethylene Propylene Diene Terpolymer) is another common type of single ply membrane you might encounter, however, and most TPO roofers will also work with this material if you need it.

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Each of these membrane styles offers different energy efficiency and installation methods depending on their precise chemical makeup. The cons of TPO roofing are minimal, and its versatility and strength have earned it the number one slot among single ply membrane roof types.

The Thermoplastic Polyolefin of TPO roofing is made from ethylene propylene rubber, with added fillers for strength and durability. This gives it many of the advantages of a rubber flat roof, but allows for hot-air welding at the seams for extra strength.

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Why would I choose a TPO Roofer?

So why, of all the alternatives, are TPO single-ply membrane roofs the fastest-growing choice for commercial roofing systems currently? Current statistics from the National Roofing Contractors Association suggest that up to 40% of new commercial roofs use it.

A full TPO roofing system is made up of the membrane layer with supporting scrim, used mostly where a flat roof is the best design. It’s manufactured off-site in sheets, with 10”, 12”, and 20” being the most common widths used in commercial roofing systems. There are slimmer sizes of Thermoplastic polyolefin for residential use. These rolls can then easily be transported to the site for installation.

Part of TPO roofing’s magic is in the way it reflects UV rays, ensuring that heat never forms within the building to start with. Given that there are few cons of TPO roofing and this major positive, it’s made a huge impact on the industry overall.

How do TPO roofers install the membrane?

After prepping the substrate of the building- which could either mean a simple clean, or full removal of the roof, if this is not a new installation- the Thermoplastic Polyolefin membrane will be ‘glued’ to the base board with bonding adhesive. Sometimes, TPO roofers will opt to fasten the membrane mechanically instead, depending on the nature of the roofing systems used and the building itself. A hot air gun is then used to weld the seams and create a single, waterproof surface on the roof.

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What insulation do you have to choose from? There’s three key types, each with their own price point and advantages. Before we look at them, however, let’s explore the ‘R-value’ of an insulation product.

R-values refer to the thermal resistance of the roofing materials, or how quickly they lose heat. You always want insulation to retain heat, so R-value is often used to demonstrate performance. In general, a higher R-value means better insulation, and it’s typically affected by the thickness of the roofing materials. The lower the thermal conductivity (K-value), the better, too, as these are inversally related.

Still confused? Don’t worry, your roofing contractor will help you make the right decision. But let’s take a look at the insulators commonly used with TPO membrane in commercial roofing systems.

  • Expanded Polystyrene: Can stand up to ground contact and doesn’t retain water. It also has the highest R-value per dollar and can be used across walls, floors, and roofs for insulation. It’s called EPS in the roof industry
  • Extruded Polystyrene: For lay people, you’ll probably notice the pink, blue, or green color that characterizes this material. It sits midway between EPS and Polyiso in price and performance. It is, however, semipermeable (perm rating of 1). It’s called XPS in the roof industry.
  • Polyisocyanurate: Also called Polyiso, it’s one of the most common insulation types you will find in roofs. It’s also more expensive than other options, but has a better R-rating and a long life, so it’s often used in commercial roofing systems.
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How much should I budget for TPO roofing?

Once you find reliable TPO roofers, you will need to decide how much you can spend on your project. Be honest about your budget, so your commercial roofers can create you an accurate quote with materials that will provide the right balance of serviceability and cost.

While prices should always be confirmed with your provider and can change considerably, they should be between $7.50 and $14.50 per square foot for a medium-average TPO roof. In high-cost areas and for complex roofs, budget for more.

What would affect your TPO roofing systems quote? Besides the size of the area, which impacts the supplies needed, the following must be considered:

  • The condition of the roof (and if it has to be revamped or removed)
  • Ease of access for roofing contractors
  • Your choice of membrane and insulation
  • The warranty coverage you want
  • Roof penetrations

What are the Advantages of a TPO Roof?

TPO roofing, when installed and maintained correctly, is remarkably long lived. It can last up to 3 decades. Of course, that’s far from the only advantage of TPO roofing!

  • Rated Class A for Fire- If you need Class A fire resistance from Underwriters Laboratories, a TPO membrane with EPDM will need very little treatment to come up to code
  • Customization- As you choose your own insulation, and have some choice in TPO membranes, too, you can easily make the perfect match for your needs and budget
  • Reflective Technology: White TPO roofing is highly reflective. In contrast, EPDM has a dark color that can be used to absorb energy if required. White TPO roofs are generally Energy Star rated as well.

TPO roofing was specifically designed to combine the features of rubber, EPDM, and PVC, to keep costs lower while still harnessing the benefits. Roofing TPO naturally resists algae, dirt and bacteria, and the flexibility of the membrane means it is less prone to punctures and tears, as well as resistant to the natural settling of the building.

It’s also highly resistant to UV, Ozone, and chemical exposure. The hot air weld on the seams also makes it stronger than taped or EPDM adhesive seams. Last, but certainly not least, TPO roofing systems are environmentally friendly

Is TPO roofing really energy efficient?

Yes! Although it seems deceptively simple, the bright white, reflective properties of TPO means UV rays bounce back, taking heat with them. This means you will need less energy to maintain a steady indoor temperature. TPO roofing systems also meets the increasing demand for green roofing material.

Not only does the energy-efficiency they provide help keep energy waste from HVAC systems lower, it also works to counteract ‘heat islands’ in urban areas, which also has a knock-on positive effect on air quality. It doesn’t use chlorine in its manufacture, either, meaning it can be recycled and used again for new TPO membranes. making this one of the major benefits of TPO material.

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Does TPO roofing have any disadvantages?

So, what are the cons of TPO roofing? As with all roofing material, it does have some drawbacks, too. As a newer technology, there is some variance in the formulas used in each membrane, meaning you need to be very selective that you are purchasing a high-quality brand. Using a reliable TPO roofer and an experienced roofing contractor will help ensure you get the best possible results.

How do I know my TPO roof is high quality?

While working with a reputable commercial roofing contractor should be all the guarantee you need that you are receiving a quality product, let’s look at some of the factors that affect TPO quality.

  • Quality of Membrane: A reputable manufacturer has the experience you need to ensure a quality product. Avoid beguiling low-cost TPO membranes that have no reputation and an unclear warranty.
  • Energy Efficiency or Fire Standards: Ensure that your membrane meets the necessary standards you desire, be that Energy Star ratings or local fire code. Remember that smooth TPO has the best energy efficiency performance. As dirt and debris adheres less, it won’t suffer accelerated aging and reduced reflective properties.
  • Longevity: Your membrane should be capable of high-temperature air welding, to ensure the seams are as durable and long-lived as possible. Strong seams make for great wind performance and no leaks. Likewise, you want your TPO single-ply roofing membrane to err on the thicker side. While it will cost a little more on the initial installation, it will pay off down the line as it has greater resistance to weathering, solar radiation, and damage. TPO membranes for commercial use can be over 80 mils.
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Can a TPO roof be repaired?

As we mentioned, TPO roofs can last up to 30 years. However, that doesn’t mean it will be impermeable for that time without the right care. Seams can rip, the membrane can be punctured by dirt, debris, or pests, and flashings can fail.

The first problem you might spot is a leak indoors, or other signs of water damage. This means the membrane has failed, and water has pooled on your insulation, eventually leaking into the roof proper.

This is not a DIY repair. You will need an experienced commercial roofing contractor to inspect the roofing materials and determine the layers used in the roofing system, where the water has penetrated the roof, and what conditions the seams are in (or if there’s other visible damage). This, coupled with the age of your roof, will help determine the next steps.

For example, on a moderately aged roof where the seams are beginning to lift, you need to take swift action to repair the seams. Otherwise they will continue to rip with wind and weather, and more water can enter. These types of physical repairs can be fairly simple- but if you wait until water enters the roof, there will be a more complicated process.

How will they determine if the water damage is bad? An infrared inspection is used. Performed just after sundown, this special technique uses the cooler temperature of the roof (vs the water) to assess how much water seepage has occurred. These areas can then be marked.

Water Damage Repair When Saturation is Low

If water saturation is below 25%, a silicone restoration can be done. Here the seams will be repaired and reinforced, the roof cleaned, and saturated insulation removed from the roof and replaced. After this, a new silicone coating will be applied to the roof. This can ‘reset’ your roof for another decade, and most contractors will even warranty it.

Obviously, this relies on the seams and membrane being in reasonable condition. If the seams are beyond salvage, single layer TPO membrane roofs can be preserved with a spray foam treatment in which the flashings will be removed and a cover board installed over the single-ply roofing membrane. This can save you the cost of a roof repair, but it will only be a temporary repair. Dual layer roofs will either need your TPO roofers to reinstall the TPO completely, or install a new roofing system.

What happens when saturation crosses the 25% threshold?

If there is too much water within the roof, a silicone treatment will not be effective- it would trap the water, making the problem worse. Regrettably, you will need to tear the roof and insulation out and expose the roof deck. If the beams are intact and free of rot, you can install your choice of TPO roofing systems from scratch. Alternatively, you could look at alternate commercial roofing, such as spray foam system, if the reason for the TPO’s failure was unsuitability for your specific conditions. A good roofing contractor should be able to asses this for you. Spray foam has a great R-value, can be re-coated to renew, and has no seams to introduce potential weaknesses. It can be retrofitted over a removed TPO roof with relative ease, too.

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As you can see, catching problems just as they start gives you a ton more options than once the problem is well established. As always, a good maintenance schedule can save you a lot of money and hassles down the line.

Does a TPO roofing system sound like the right roof for your commercial building? We are always on hand to help you initiate the quote process, or simply to answer questions you may have about this versatile technology. Feel free to reach out to us today.

For more information see ATC Commercial Roofing.