Flat Roofing Guide:

Flat Roof Repair
Should you fix or replace your old flat roof? See why repairing that roof is MORE EXPENSIVE than getting a new IB's lifetime roof.

Single Ply Roofing:
Benefits of Single Ply Roofing Systems vs. the old asphalt, BUR, modified bitumen roof.

Solar PV Guide:
Principles of how Solar PV works, and ways to get Free Electricity / Speed up the pay-off period!

Green Roofs: Roof top garden design, benefits and price guide. Green roofing creates healthier cities and makes a roof last much longer, when built correctly.

Knowledge Guides:

Roofing - Learning center contains Do-it-yourself roofing projects that show steps to repair flat and low slope roofs. Detail roofing guides help you solve common roof problems. Homeowners guide to roofing explains benefits of different roof materials and technology.

PVC vs. TPO flat roofing - choosing between quality and price

When choosing the right Cool Roof technology, the two most common choices are the PVC and TPO single-ply membranes. For many business and home owners, price is often a decisive factor, while many fail to investigate the fundamental differences between the two seemingly identical products. The truth is that the only three common factors between PVC and TPO are the 'cool roof' attribute and the hot-air welded seams, and the fact that they look very similar to each other.

Today, PVC membranes such as that Produced by IB Roof Systems has a proven track record of 30 years of great performance and ZERO material failure. Some IB installations dating back as far a 1979 are still performing well on the roofs of various Public, Commercial/Industrial and Residential buildings. Read more about benefits and many product options of IB's PVC Roofing.

TPO roof failures: Premature membrane curing and cracking

The image above shows a 10 years old failing TPO installation. Due to poor formulation, the membrane has cured (lost its elasticity and hardened) and the expansion / contraction created cracks which now let the water in. This problem can and likely will happen to many TPO installations from various manufacturers. Lack of testing and UL certifications follows many brands of TPO roofs. As its formulation changes too rapidly, many manufactures choose to just ship the product, without proper evaluation. Another problem associated with various TPO roofs is poor weld quality, which causes seams to come apart from each other and allows the wind to lift up the entire sheet, and eventually blowing off parts or the entire roof.

Industry reports on TPO failures and potential problems

Here is and excerpt from RSI Magazine - a well respected industry publication. The article "TPO problems require a closer look" was written by Mike Russo, RSI's Editor-At-Large, written in 2001:

... The recent TPO membrane cancellation is not the first time that problems with these systems have been experienced in the field. Difficulties with black TPO membranes have also been reported. This is not surprising considering the heat-sensitive nature of TPO compounds. Experience to date with fully adhered TPO membranes also shouts "caution." With a thermal expansion and contraction up to five times higher than reinforced PVCs, fully adhered TPOs theoretically run the risk of de-lamination or insulation facer peel. The quality of the adhesive bond to some TPO membranes has also been questioned. The use of felt-backed TPO is an obvious solution here.

...

The lack of a long track record for TPOs is the most common criticism thrown out by other single-ply roofing competitors. Most TPO suppliers have less than 10 years of experience manufacturing their products. Suppliers in Europe have greater experience, but these systems are inherently different than what's being marketed here. For one thing, average thickness is about 60 mils (no product is sold at less than 48 mils) compared to 31-45 mils of polymer in roof membranes sold in North America ...

Analysis of the state TPO roofing in 2008:

After a wave of formulation changes in 2000-2001, most of TPO membranes on the market today and those installed in the last 7 years, are involved in a very expensive experiment, which is designed to find out how long these TPO roofs will last. This experiment is performed at the expense of the Roofing Contractors and Building owners, lured into using TPO roofing products by its lower cost (compared to PVC roofing) and the questionable quality. There are numerous 'off-the-record' talks among the roofing professionals about on-going problems with TPO from various manufacturers.

Driven by the goal to increase profits and minimize costs, TPO manufacturers keep on changing their formulations, releasing batches of 'Untested' roofing membranes, and hoping for the best. Their ultimate goal is to create a product with the lowest cost, and adequate quality. Unfortunately the nature of TPO membranes, shows that a trade-off in costs is directly related to the product quality. TPO has an average 15 mils thickness of its Top Ply, while the total membrane thickness ranges from 45-60 mils. Top ply is what essentially makes the roofing membrane and keeps it from leaking as well as UV-stable. The rest of that 30-45 mils is the invisible, filler-rich bottom ply. Due to excessive use of cheap fillers in the bottom ply, is the cause of most product failures of TPO membranes from various manufacturers. However if these manufactures increase the use of quality ingredients in TPO membranes, they will become too expensive and not-competitive against PVC.

History of TPO in the United States

For over 30 years PVC has dominated US commercial roofing market when it came to quality and longevity. PVC has a proven track record to remain leak-free beyond it's expected life-cycle, while it was still weldable, meaning it is easy to fix a PVC roof even 20 years after it was installed. While other technologies such as Epdm and Modified Bitumen (mainly due to their lower cost) where more widespread in terms of sq. ft. installed, PVC was and still is the roof of choice for those who need the length of warranty, energy savings and the overall quality flat roof.

In late 1980's and early 1990's, TPO became very popular with North American roofing manufacturers. It was meant to replace Epdm as the most installed commercial roofing product, and to get rid of PVC roofing completely. The reasoning behind such plans is that TPO is very cheap to produce, compared to PVC, and was supposed to have all the benefits of PVC roofing such as 'permanent' hot-air welded seams, cool roof rating and ease of repair. Despite ambitious plans, reality turned out to different.

By 2001 most TPO manufacturers had to halt the production of their products due to numerous seam failures and premature curing of the membrane. These manufactures were changing the formulation of their membranes, trying to make their TPO products last longer while still competitive. The dilemma was that to achieve the right mix of higher quality, yet more expensive ingredients and cheap fillers. Use of inexpensive filler reduced the price of the final product, but also decreased the quality and longevity of TPO.

Final Words:

If you are deciding whether to use PVC or TPO, rememberer that by choosing a slightly cheaper option (TPO) you become a participant (and in some cases the victim) of expensive experiment, while receiving questionable savings. Bear in mind that earlier batches of TPO tended to cure prematurely, making them virtually non-repairable using hot-air welding. There are also numerous cases of seams failures on many TPO installations. Unfortunately you will not find any information on this topic, because TPO suppliers will never disclose it to the general public, and will usually solve it privately. However, this information may, and probably will surface soon, if too many TPO roofs begin to fail. We suggest you choose the proven technology, which in the long run, will be cheaper to install and maintain.

Comapre IB PVC Roof - use flat roofing search: Custom Search

Did you like this article? Send us your comments.

We would like to get your feedback, so we could improve the quality of this article, and add information important to you! Please take a moment to send us your comments and suggestions.

This form is for article comments only. If you would need a roof replacement, please use our roof estimate request form.

Please note: This feedback form uses a SPAM filter, and requires a real e-mail address. We will not give your information to anyone.