TPO Welding – The Complete Guide

Do you need to complete a welding job but don’t know what material or tools to use? The Hapco team is here to help. Keep reading to learn about TPO welding, its benefits, and what tools do the job best.

What is TPO and What Does TPO Stand For?

TPO—which stands for thermoplastic polyolefin—is a single-ply white membrane used for both commercial and residential roofing jobs but is especially more present in a commercial setting. The white color of TPO allows it to reflect rather than absorb heat which makes it a much more energy-efficient material than bitumen for example.

By using TPO for either commercial or residential roofing, you can keep both your indoor and outdoor spaces cooler during hot months. Depending on what shape the roof is in, TPO can last for as long as 35 years.

Commercial roofing work in progress

Why Use TPO for Welding Jobs?

Energy efficiency

One of the main perks of TPO roofing is that the white color of the material allows it to reflect rather than absorb heat. This process keeps both indoor and outdoor spaces cooler during hot months which makes it an ideal roofing material for warmer climates.


In addition, TPO can last for as long as 35 years, depending on what shape the roof is in.


Furthermore, TPO is fully waterproof, allowing it to repel water that collects on the roof and prevent it from leaking below which is ideal for roofs that are flat or have a low pitch. Since roofs typically lower than 2/12—collect water easily and don’t drain effectively, water damage is quite common if using standard asphalt shingles which aren’t waterproof. TPO roofing is therefore a great alternative.

When compared to PVC or other welding materials and methods used for roofing jobs—including asphalt shingles—TPO is:

Quicker to install

More durable

More reliable

More versatile

More cost-effective

More environmentally friendly

TPO Welding – How to Weld TPO

Whether it’s your first time or your 50th time using this material, these six steps will help you get your TPO welding job done right:

  1. Clean the overlap welder nozzle: This will remove debris and ensure proper airflow.
  2. Set the ground speed at a comfortable rate: Ground speed is the rate of travel of a TPO welding machine across the ground. A ground speed that’s too high or too low will result in poor welds.
  3. Set the temperature: Always start low, then increase the TPO welding temperature by increments of 100°.
  4. Find your weld window: Perform a few test welds before starting the weld. Only change one variable at a time for the most accurate results.
  5. Mark your welds: Mark each test weld on the TPO membrane to track your progress. Make a note of the thickness along with the weld temperature and speed.
  6. Perform a pull test: A pull test helps ensure the weld is accurate.

What are the best TPO welders?

We recommend two heat tools for any TPO welding job: automatic welders and heat guns. The scope of the welding job at hand will determine which TPO welding machine will provide the best results.

tpo welding using a BAK heat gun nozzle

Heat Guns

A TPO welder —like the BAK RiOn— is more effective for welding jobs that require precision, such as in narrow spaces. These handheld hot air welders are durable, easy to maintain, and perform optimally. Check out additional product features below:

Most flexibility
Best for corners and short welds
More precision is narrow spaces
Wide range of accessories for even more precision
BAK Roofon Multi on the roof

Automatic TPO Welding Machine

Automatic TPO welding machines—such as the BAK LarOn 21—are best suited for welding jobs completed on large surfaces. That’s because these hot air welding machines are bigger and sturdier, thus more equipped to tackle heavy-duty jobs. Here are several features of the BAK LarOn 21 automatic welder:

Best for bigger projects
Fastest way to weld TPO
Durable welding machines
Automatic drive

The Right Heat Tools for Every TPO Welding Job

If you have questions about a particular product in our collection or can’t find the one you need, connect with us today. One of our team members will reach out to you promptly to make things right.

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