Let’s talk about TPO roofing systems.If you’ve seen a bright white roof, then you may be familiar with TPO roofing. As one of the most common roof types of big commercial facilities, TPO has some of the best energy savings for single-ply membrane roofing!
For commercial buildings with a low-slope or flat roof, a TPO roof is one of the most popular systems.
One reason is cost, but it doesn’t stop there.
There are several other reasons you may want to invest in a TPO roofing system.
You’re going to learn everything you need to know about TPO roofing, so you can make an educated decision about your next roofing project.
WHAT IS SINGLE-PLY MEMBRANE ROOFING?
Single-Ply Membranes are sheets of rubber and other synthetics that can be ballasted, mechanically fastened, or chemically adhered to insulation creating a layer of protection on your commercial facility.
While Single-Ply Membrane Roofing is one of the most well-known types of commercial roofing material, there are several types to fit your budget and facility needs.
There are two main types of single-ply membrane commercial roofing: Thermoplastic Polyolefin (TPO) and Ethylene Propylene Diene Terpolymer (EPDM).
They differ in their chemical makeup, how they are installed, and their energy efficiencies.
What is TPO Roofing?
TPO stands for Thermoplastic Polyolefin. A TPO roof system is a single-ply roofing membrane, supported by a properly installed solid substrate – often an engineered insulation system – on flat or low sloping roofs.
The TPO roof membrane comes in different thicknesses – commonly 40-mil to 80-mils or thicker.
And quality varies widely by manufacturer.
The membrane is attached to the roof by mechanical fasteners, adhesives and various methods of heat welding to form watertight seams and seals around roof edges and penetrations.
As is the goal with most roofing systems, TPO roofing systems form an effective barrier designed to repel water, snow and ice.
To keep your building and its contents safe and dry.
While your TPO roofing system may have unique design requirements, the graphic below shows one common type of install.
Thermoplastic Polyolefin is a single-ply roofing membrane that is one of the fastest-growing commercial roofing systems on the market. TPO roofing systems are made up of a single layer of synthetics and reinforcing scrim that can be used to cover flat roofs.
TPO membranes are manufactured in sheets that are 10, 12, or 20 feet wide. These sheets are then rolled up and taken to the commercial facility.
TPO has gained industry acceptance with the natural reflective surface to reflect UV rays. As reported by the National Roofing Contractors Association (NRCA) TPO takes up about 40% of the commercial roofing market share.
Thermoplastic polyolefin, or TPO for short, is a type of single-ply roofing material that is heat-reflective and energy-efficient. In laymen’s terms, TPO roofing belongs to the broader category of “rubber roofing” materials. It contains a blend of rubbers and other elements (fillers) that add to its durability and flexibility. TPO roofs (for both commercial and residential roofing) are growing fast, especially where we do roofing in Maryland, DC, and northern Virginia.
TPO roofing was introduced in the 1990s as an economical alternative to PVC roofing. Over the last several decades, TPO has become popular due to its superior performance as a flat roof system. Primarily, TPO is touted as a more energy-efficient alternative to EPDM and PVC. And as demand for more energy-efficient roofing increases, so does the popularity of TPO.
Image Credit: Versico Roofing Systems
Fully Adhered TPO System
- TPO Membrane
- Bonding Adhesive
- Fasteners & Plates
- Insulation System
- Roof Deck
TPO Roof Membrane Details
You may be wondering…
What is TPO roofing material made of?
The single-ply TPO roof membrane actually consists of at least three layers, bonded together to create a single membrane.
Thermoplastic Polyolefins (TPOs) are polypropelene based materials that have been modified to provide better tension strength, flexibility and impact resistance, while retaining the chemical resistance of PP products.
While TPO membranes contain thermoplastics, they may also contain EPR or EPDM rubber and other compounds (depending on formulation) like talc, fiberglass or carbon fiber to amplify durability and effectiveness.
TPO membrane formulation include things like: pigments, fire retardants, antioxidants, lubricants and UV absorbers – all designed to enhance performance.
A single-ply re-inforced TPO roof membrane contains the following layers:
- A top layer formulated with UV blockers and abrasion resistant compounds
- An encapsulated middle layer called “scrim” which is a high-strength polyester mesh material designed to add structure to the membrane, while increasing puncture resistance and tensile strength
- A base layer compounded for strength, adhesion and flexibility
Some TPO membranes also include a fleece backing that is used for certain installation requirements.
After the existing substrate is prepared, either by cleaning or removing the existing roof, the insulation is installed. There are a few types of insulation options the facility manager/owner can choose from:
- Polyisocyanurate (Polyiso) – The most used insulation type for roofing applications, Polyiso is more expensive but pays off with a higher R-value rating.
- Expanded Polystyrene (EPS) – With the highest R-value per dollar, EPS is used for roof, wall and floor insulation. EPS can be used for ground contact and does not retain water over time.
- Extruded Polystyrene (XPS) – Usually defined by the blue, green or pink color, XPS falls in-between Polyiso and EPS in the range of price and performance. XPS is semipermeable with a perm rating of 1.
The TPO membrane can be attached to the cover board with a bonding adhesive or mechanically fastened. When the membrane is rolled out, the contractor then returns and uses a hot-air gun to hot air weld the seams together.
TPO Roofing Manufacturers
High-quality TPO roofing systems are offered by industry-leading manufacturers. Here are a few of the top companies offering TPO roofing systems. Your professional roofing contractor can help you determine which system best fits your needs.
What are the Benefits of a TPO Roof?
If properly installed and maintained, a commercial single-ply membrane roof can last 30 years. There are quite a few other benefits of single-ply membrane roofing systems:
- Customer Choice of Insulation – Since single-ply membrane roofing does not include the insulation factor, as a customer you have more options to choose from to insulate your facility’s roof.
- Class A Fire-Rated – TPO membranes and EPDM can achieve Underwriters Laboratories (UL) Class A fire resistance listings by adding fire retardant chemicals during the manufacturing process.
- Reflective or Retentive – TPO is generally white and highly reflective. On the other side of the spectrum, EPDM is often described as “Black Roofs,” due to the natural dark color of the membrane.
A TPO roof offers substantial benefits over other roofing systems in key areas.
Here are a few benefits of a TPO roofing system:
Punctures can lead to leaks. TPO offers increased puncture resistance over other commonly used roofing materials. The quality of substrate design and installation techniques can play a big role in puncture resistance, so be sure to choose a first-rate roofing contractor.
Reflective TPO roof membranes come in white and other light colors and can help save money on energy costs compared to dark-colored EPDM. Some buildings see a dramatic drop in heat absorption when using a light-colored TPO roof.
Value & Cost-effectiveness
When comparing costs to other systems like commercial metal roofing, TPO roofing systems offer one of the most cost-effective roofing solutions available, offering a great balance between performance and price. Flexibility of materials and faster installation delivers a lower cost install.
Long-term Weather Resistance
TPO offers superior resistance to long-term heat and damaging UV rays from the sun. TPO resists shrinking so seams and sealants stay in place over time.
Welded Seam Strength
A weather-tight roofing system depends on the strength of its seams. Welded seams as part of a professionally-installed TPO roof system, create a monolithic membrane across your entire roof.
How to Select a TPO Roofing Contractor
TPO roof installation requires an experienced commercial roofing contractor. TPO roofing is a specialty field of roof installation. And complex roof systems require careful craftsmanship and adherence to strict manufacturer standards.
Look for a TPO roofing contractor with the following qualifications:
- Is licensed, bonded, and insured
- Experience installing your type of flat roof on multiple projects
- Experience managing staged roofing projects that may require parallel tear-off and installation
- Experience working with insurance companies on damage claims
An experienced roofing contractor can help you avoid leaks and major problems and provide a roofing systems that lasts for decades.