TPO and modified bitumen are the most common types of commercial roofing systems. Modified bitumen roofing has been around since the 1970’s and TPO was developed later in the 1990’s. They are both great systems for hot and dry weather and as with all options, they both have advantages and disadvantages.

Modified Bitumen Roofing

Modified bitumen has been the go-to for commercial roofing for some time because they are practical and lower in cost. This option served as an upgrade to traditional asphalt roofing and offered enhanced longevity and flexibility. Many contractors, however, have stopped offering these systems because of the disadvantages that have recently been discovered.
Modified bitumen roofing was improved by adding substances like APP (atactic polypropylene), as a way to ensure the new systems could resist UV light, oxidation, cracking, and blistering. Unfortunately, several manufacturers have been found to skimp on the amount of APP which means the modified bitumen roofing produced is not able to stand up to the current challenges roofing faces. The granulated surface of modified bitumen was also added to provide additional UV resistance, but only this surface only makes it more difficult to identify cracks and leaks. These roofs also come with a serious fire hazard should any open flames be present during installation.

TPO Flat Roofing

Thermoplastic Polyolefin (TPO) roofing is widely considered to be the next best thing in large-scale roofing. It can be installed in one of three ways; ballasted, fully adhered, or mechanically fastened. It is a popular commercial roofing option because of the numerous benefits it provides for building owners.  The single-ply membrane is tough and tear resistant and stands up against chemical and grease spills, which are common with commercial roofing. They are also UV-resistant and fully recyclable which is popular benefit in today’s greener world. There are also no plasticizers in the insulation which only adds to its environmentally-friendly appeal.

You can apply TPO over existing metal or bitumen roofing so long as your current system is secure. This saves you time and money because you will not have to tear off and dispose of old roofing. TPO can be reheated which means you can weld seams when needed. They have a smoother surface than the granulated surface of bitumen roofing, which makes them easier to clean. TPO membranes are typically much thicker than other roofing options, which better protects your roof from falling debris and tears. Installation needs to be done properly as most problems identified with TPO have been related to poor installation, specifically seams not being welded properly. When you work with an experienced roofer, you can be assured that your TPO roofing will be installed correctly and will last longer than expected.


Whatever roofing system you decide to go with, we have the knowledge and resources to get your next roof installed with precision and quality. TPO may be the preferred option but we can discuss all options with you and we are here to answer any of your concerns regarding your next roofing project.

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