TPO roofing systems are the most common commercial roofing system available, making up roughly 40% of the commercial roofing market share. If you've ever passed by a commercial building with a bright white roof, then you’ve more than likely seen a TPO roof!
Thermoplastic polyolefin, or TPO, roofing is a single-ply membrane roofing system that originated in the automobile industry and is widely considered one of the most affordable, energy efficient, easy to repair, and common commercial roofing types today.
Below, we’ll take you through the most common TPO FAQs, as well as some of Simpson Unlimited’s own best practices so that you can understand everything there is to know about the most common commercial roofing system available.
What is TPO Roofing?
Like PVC and EPDM, TPO roofing is a single ply membrane roof, meaning it’s made of one single sheet of synthetic material reinforced with a polyester scrim that’s mechanically fastened, adhered, or ballasted using river rock over insulation to create one single layer of protection.
A nearly completed TPO roofing system.
The seams of each TPO sheet are heat-welded together, making the roof monolithic. Compared to the other singly ply membrane roofing types, TPO is installed nearly identically to PVC, whereas the seams of EPDM roofs need to be cleaned, primed, and sealed using EPDM seam tape.
TPO is one of the cheapest commercial roofing systems available thanks to its lower material cost versus EPDM and PVC. All of these roofs are in the single-ply family so naturally one of the drawbacks is that your roof may be more vulnerable to membrane punctures that can lead to leaks.
How Much Does TPO Roofing Cost?
TPO is considered one of the cheapest commercial roofing options available.
TPO is generally about $0.50 per square foot for material, whereas EPDM and PVC usually cost around $0.55 and $0.77 respectively. With labor included, the price for TPO can be anywhere from $5 to $15 per square foot.
Certified roof inspectors will be able to spot potential hazards, like this improperly waterproofed penetration made by another contractor.
TPO roofs come with a large ensemble of prefabricated accessories, meaning they can accommodate most commercial buildings. Another one of TPO’s big price differentiators is its easier, more straightforward installation process that requires less labor.
What Factors Affect TPO Roofing Costs?
The biggest and most cost-affecting element of any roofing service or building restoration is the labor.
The number of roofers required to complete a job safety and within a predetermined time frame is always the biggest price determinate, as is access to the roof. If a roof is difficult to access and requires specialized equipment to safely reach, the equipment rental as well as the mobilization can both have a dramatic impact on overall costs.
Other roof-specific factors include whether or not special permits are required (this is of particular concern in DC), the number of penetrations, and whether or not the roof is wide open or congested with different HVAC units, anchors, or other obstructions.
The assembly of your roofing system is another critical component, since its condition will affect whether or not we’re tearing off the existing roof down to its structural deck or doing a more cost-effective overlay or roof recovery, where any areas of wet insulation have to be removed and replaced.
Knowing the deck type will also determine which attachment method (mechanically fastened or adhered) we will use for installation of the TPO membrane and insulation. Lastly, the type of insulation used and number of layers which have a direct effect on the material and labor cost of the project.
How is TPO Roofing Repaired?
TPO roofing repairs are relatively easy compared to other roofing systems.
Thanks to its heat-welded components, repairing typical punctures is often as easy as cleaning the TPO membrane and heat welding a new piece of TPO over the area. That said, TPO roofing repairs require special equipment (i.e hand welders) and experienced roofers to be done right which ensures you’re less likely to have a “Pete and a truck” roofer on your building performing service.
How is TPO Roofing Installed?
The two most common methods of TPO roof installation are mechanically fastened and adhered.
Mechanically fastened roofs are screwed through the seam and the insulation down to the structural deck with special barbed plates and #14 or #15 fasteners. This is a more cost effective method but doesn’t offer as much wind uplift performance. Rhinobond is another variation of a mechanically fastened system with unique, albeit more expensive, plates. Rhinobond is attached to the structure then induction-welded to the membrane once the membrane is in place.
Adhered roofs are chemically glued and maintain a smooth, flat surface flush with the insulation and substrate, offering a higher wind uplift performance and a more aesthetically pleasing look. Looks will cost you though since adhered is on average more expensive.
TPO roofs can also be ballasted, but this is an option we tend to avoid because of how challenging it can be to find leaks.
What Are the TPO Roofing Insulation Types?
There are 3 major types of TPO insulation, all different costs and R-values. The R-Value is the metric for the material’s ability to resist thermal movement. In short: the higher the R-value, the more “insulating” the material is and the more effective it is at retaining heat.
Polyisocyanurate, or polyiso, is the most common insulation type because it has the higher R-value per inch of insulation.In most cases polyiso is a great fit but because of its flammability, it may not be suitable for buildings with certain fire restrictions or combustible deck types such as wood (ex. Class A).
Expanded Polystyrene, or EPS, is a more cost-effective option that offers a higher R-value per dollar, but is usually only used on tapered roofs.
Extruded Polystyrene, or XPS, is defined by its blue, green, or pink color and falls in between polyiso and EPS for price and R-value.
What Are the Advantages of TPO Roofing?
Thanks to its heat-welded seam technology, TPO roofs are monolithic and have a much higher water resistance. The material is noticeably more cost effective than other roofing types, and it’s one of the least expensive roofs to install and maintain.
TPO also offers a host of various installation options and insulation types, allowing the building owner/manager more flexibility. Because it’s reinforced with a polyester scrim which allows for expansion and contraction, the roof is more weather resistant than many other roof types.
TPO roofs also look aesthetically pleasing and are energy efficient thanks to their heat and UV resistance, reflectivity (SRI), and emissivity.
They also have a wide array of prefabricated and custom accessories for wider roof compatibility and easier installation.
It’s no wonder TPO roofs are so common. They’re relatively inexpensive, easy to install, have a host of prefabricated accessories, and are energy efficient, so what’s not to love?
If you’re ready to start your next roofing project, send us your details below so we can get to work!