Pros and Cons of TPO Roofing

If you are looking to install a single ply roofing membrane that will be energy efficient and are evaluating your options, consider TPO (thermoplastic olefin) roofing. TPO is touted to have the benefits of two of its direct competitors EPDM and PVC roofs, but without the drawbacks and extra costs. This means that a TPO roof is as UV-resistant and as heat-resistant as EPDM, and as heat-weldable as PVC. As any roofing material, TPO also has its disadvantages and shortcomings that are primarily due to the fact that TPO is a fairly new roofing material on the market and research still continues to find the most durable and long lasting product formulation. Before purchasing a TPO membrane for your home or commercial building, carefully consider all the pros and cons of TPO roofing.


Estimated 1500 s.f. Flat Roof Costs in US Average Flat Roof Costs in US
Rubber Roof
Rubber
$7065
TPO Roof
TPO
$7455
PVC Roof
PVC
$8055

See costs in your area Start Here - Enter Your Zip Code



We recommend that you read our overview of MRCA TPO Advisory (from 2010) which it has issued for commercial roofing contractors, and what it means for building owners.

What is TPO?

The TPO membrane was first introduced to the roofing market in the early 1990’s as a more economical and efficient alternative that was thought to replace PVC roofing products. TPO is a single ply roofing system that consisting of a thermoplastic polyolefin membrane. This membrane is composed of three layers:




1. TPO polymer base.

2. polyester-reinforced fabric center (scrim).

3.thermoplastic polyolefin compounded top ply.

Common fillers used in TPO manufacturing include but are not limited to: talc, fiberglass, carbon fiber, wollastonite, and Metal Oxy Sulfate. Popular rubbers used in TPO manufacturing include ethylene-propylene rubber and EPDM.

Benefits of TPO Roofing

Economical

One of the factors that makes TPO roofing attractive both in residential and commercial construction is its reasonable cost. TPO offers many of the same benefits as PVC roofing, such as hot-air weldable seams and energy efficiency, but at a lower cost.

Fits different home styles

Many homeowners appreciate the fact that TPO is manufactured to look great on many different types of homes. TPO is available in white, light grey and black reflective color options. Now you do not need to get a white roof to enjoy the energy saving and reflective properties. Latest technologies enable all colors of TPO roofing membranes to be UV resistant and “cool”.

Durable

In comparison to other thermoplastic membranes, TPO resists mold growth, dirt accumulation, tears impact and punctures. It is made to be flexible and can allow for a home’s or building’s movement or settling. Reinforced TPO membranes can handle a building’s thermal expansion and contraction more effectively than other single ply roofing products.

Ease of installation

In general TPO membranes are manufactured with wider sheets and are light weight. This means that the material is easier to install and there is less seams. Less work and time associated with the installation translates into direct savings for you for the cost of installation.


Estimated 1500 s.f. Flat Roof Costs in US Average Flat Roof Costs in US
Rubber Roof
Rubber
$7065
TPO Roof
TPO
$7455
PVC Roof
PVC
$8055

See costs in your area Start Here - Enter Your Zip Code



Energy Efficient

The energy efficiency of TPO roofing membranes makes them highly attractive to home owners who want to have the benefits of savings on their cooling costs as well as help the environment by reducing the carbon footprint. TPO’s membrane’s white reflective surface exceeds the EPA’s ENERGY STAR requirements and white, tan and gray are listed with the Cool Roof Rating Council. This means that having a TPO roof on your home or building will keep the interior thermally comfortable on hot summer days while reducing your air conditioning costs.

Disadvantages Of TPO

Questionable longevity

One of the biggest disadvantages of TPO is that it is a really young roofing technology. It has been around only for about 10 years and manufactures are still trying to figure out the best chemical formula that will make the product durable and long lasting while maintaining a competitive price. Finding this right formula has been a challenge for many manufacturers and over the years there have been many documented instances of seam failures and material failures such as membrane curing and cracking. New and improved formulas continue to be tested, but it is not possible to tell at this point how long a new TPO roofing product will last. If you choose to purchase a TPO roofing membrane, it is advisable to get it from a manufacturer that has been around since the beginning of TPO production, as they will most likely have the most long lasting formulation available on the market today.

Does not stand up well to heat load

TPO roofing membranes have been noted to have an issue of accelerated weathering when subjected to high thermal or solar loading. This problem has been specifically documented in the Southern states that get a lot of heat and sun throughout the year. The MRCA committee that issued the report based on their research, recommended the following to contractors: “If situations exist that may commonly elevate temperatures over 160 degrees or increase solar loads beyond “normal” question the manufacturer as to the suitability of their product for the situation; consider changing the product to a material that will clearly withstand the loading.


Estimated 1500 s.f. Flat Roof Costs in US Average Flat Roof Costs in US
Rubber Roof
Rubber
$7065
TPO Roof
TPO
$7455
PVC Roof
PVC
$8055

See costs in your area Start Here - Enter Your Zip Code



About Leo - Roofer

Roofer with a vision - I've been in commercial and residential green roofing since 2004, and specialize in Flat and Metal Roofing, as well as Roof Estimating Software.

29 thoughts on “Pros and Cons of TPO Roofing

    1. leva Post author

      Hi Bill,

      Walkways might be required – this will depend on manufacturer and architect. It should be installed around HVAC units and in areas of foot traffic.

      Most cost effective way is to purchase and install them – there is no other way.

      Reply
  1. FRANK

    WOULD 1′ POLYISOCYNURATE BOARD BE A SUITABLE UNDERLAY FOY 0.06 TPO ROOF AND WOULD YOU RECOMMEND MECHANICAL FASTENING OR IS THERE A SUITABLE ADHESIVE.

    Reply
  2. brandon

    I would highly recomend using walkways not only to protect your roof as well as the look. most iinspectors require them as well

    Reply
  3. Dave Heimer

    I have a passive solar home in Sacramento CA. It is a flat roof tar and paper. I also have 4-8 inches of dirt that helps with the insulation of the house. Roughly 2000 sf of the roof is covered with dirt and plants. The house was built in 1978 and I purchased the home in 1997.
    When I exposed the tar roof to cut in some solatubes a couple years later, the roofer who did the job remarked how the tar had barely crystalized because it was covered with dirt. He thought that that roof would last forever.

    I’m familiar with TPO because of my previous job where we re-roofed commu ication shelters and I was impressed with the warranty that the roofer and manufacturer gave us. Now I’m wondering if TPO would be right for me at my home but I would like to know how it stands up or if it would break down from being in constant contact with dirt. Hey, do you guys need a test home? Thanks, Dave

    Reply
  4. todd stroud

    Would TPO work as a roof and deck combo? The upper floor of a duplex is using a roof over the lower porch as a deck. I would like to put down a good roof and then put outdoor carpet on top to protect it from puncture. There is also the issue of trying to waterproof the handrail posts, which attach to the roof.

    Reply
  5. corrugated plastic roofing

    To repair little splits and blisters in felted roofs,
    open up the top layer of the felt with two knife cuts
    at right angles. Built-up roofs are built flat and as one so
    when a leak occurs it can be difficult to place the location of it, causing one to have to dismantle the entire roof.
    Understand of course that these kinds of costs are for
    new contemporary homes and simply supply you with a limited capacity of
    electric power.

    Reply
  6. Rob

    GAF Manufacturer’s Extreme TPO will stand up to the heat. TPO has actually been around for over 20 years now. There were some bad TPO’s that came out initially, but today most manufacturer’s TPO is of better quality than the first formula’s that came out.

    Reply
  7. cant say

    Just a few years ago (about 5) a study was performed in los vegas I believe, where the weather is dry and hot. they adhered TPO membranes from several different man. and found that they weather very badly in short amount of time. only like one man. came out with a decent report. within like 7-10 years. I cant remember who it was done by (one of the roofing organizations). If things change since then, then you are probably safe but for me it is still too early to take a chance with that type of membrane cause repairs are not very cheap and easy. I still see today a lot of seams curling up and even though their are tapes and such, even those fail as well.

    Reply
    1. TPO Roofer

      Christopher,

      It’s hard to say, because TPO material (for cars for example) has been around very long time. I’d say most big name TPO manufacturers today, started at about the same time… but the problem is – not when they started making TPO, but what formulation / generation you actually buy – because it’s pretty much impossible to determine this by reading labels on material rolls, and not a single manufacturer publishes this data.

      Basically it’s often a gamble – some roof suppliers still sit on inventory of 1 or even 2 generations old product.

      As many have pointed out, because of all these reformulations, many products can only be installed OR are recommended to be installed with seam tape and primer / adhesive. This pretty much negates ANY advantage that TPO may have vs PVC, and makes it BETTER to use WHITE EPDM RUBBER instead of TPO, since white EPDM is still cheaper, and seams will hold better!

      Hope this helps – Leo

      Reply
      1. Jon

        We had the Versico /carlisle 60 mjl too installed early this year. Of course, after 1 year its still great but I’m hoping it’ll last 15 years minimum. It has a 20 year warranty.

        Am I supposed to go up and check seams all the time?? Anybody know how this brand is? Is it considered one of the better manufacturers?

        Reply
    1. TPO Roofer

      Joye,

      You can have 1 layer or 10 – the difference is in cost, which goes by total THICKNESS of your insulation, which is converted to R-Value.

      In most cases roofers install POLY-ISO rigid foam insulation – it can go from 1/2″ per sheet to 3.3″

      1 inch of ISO is 6-R, 2″ = 12-R, and so on… 3.3″ is 20-R

      You can stack as many sheets as you want, as long as fasteners are long enough to hold it down properly.

      I’m not sure what FR-10 is

      Good luck

      Reply
  8. AJ scammler

    FR-10 is a fire sheet. It’s a gypsum impregnated fiberglass sheet. Comes in a 10 square roll by four feet tall. Is itchy but gives a class a rating to the roof.

    Reply
  9. Dave

    I’m thinking of installing a TPO roof and i live at a high altitude (7000-ft) in New Mexico where the UV radiation is intense. Do anyone know if it has been used in New Mexico? How well does it perform?

    Reply
    1. Paul Sumner

      I noticed your question on TPO being used in New Mexico. We are in New Mexico as well, and wondering the same. If you have gotten any further information would you mind passing it along. We are going to have a sun room and shop done this January.
      Thanks in advance if you are able to pass along any information.

      Reply
      1. Dave

        The roofer uses Genflex TPO roofing. So, They may guarantee the TPO for say 20 yrs but what about the seams. It comes down to skilled labored. If the seam isn’t done correctly all bets are off. Then, who will pay for the possible mold remediation and other damage? So, I decided to pitch the roof and do asphalt shingles.

        Reply
  10. Skip Slade

    Our roof deck covers two bedrooms below and serves as patio during warmer months with foot traffic and patio furniture atop. The current roof is a twenty to thirty year old modified bitumen that is starting to crack. There are two soft areas, one with water leaking down to the plywood substrate.

    Two roofers have submitted estimates. Each recommends installing one half inch insulation board (IsoGuard in one case, an unspecified brand in the other) over the existing roof with a single ply membrane (TPO for one, IB Roofing PVC for the other) as the final cover.

    Will isoboard insulation almost certainly deform when subjected to the intended use described above? Can it successfully bridge twelve to eighteen inch soft areas? Can I expect either the TPO or PVC to perform at least as well as the modified bitumen? Does the slippery nature of both TPO and PVC when wet render them unsuitable for use as a recreational walking surface?

    Thanks in advance.

    Reply
    1. TPO Roofer

      Skip, excellent questions … not most reefers ever think about these.

      So first – do not hire either of the roofers that gave you quotes already! Here is why:

      1) If you have soft spots, the Mod-Bit must be removed and substrate fixed. I know this means more $$, but if you live wet stuff there, it will only cost more money later, and you would have to remove new roof to fix the problems.

      2) ISO insulation WILL deform and should not be used if you have foot traffic. Also white TPO/PVC should not be used either! I will discuss this below.
      ISO will not “bridge” soft spots.

      What I recommend you do:

      1) Remove old roofing and repair rotted substrate.
      2) (OPTIONAL) If you need insulation, install 1-3″ of ISO Board. I recommend a minimum of 2″ to increase thermal resistance. ISO should be mechanically attached (screws and plates) OR fully adhered with special 2-part insulation adhesive (expanding adhesive foam).
      2a) Install 1/2″ or 5/8″ DENS DECK or other moisture resistant rigid substrate. This will be your “walking surface substrate”. DensDeck is very hard, and will not break when you walk on the roof later.
      3) Install special Deck Membrane. There is no TPO product for this, but there is an EXCELLENT IB PVC DeckShield product that we installed on many roof decks with great success! You may look for alternatives, but I believe that DeckShield is the best there is in US.

      DeckShield is made for foot traffic / grills / patio furniture and to provide excellent water tightness. Now the warranty on it is “only” 10 years, but it should last at least 30, with proper installation and if you don’t abuse it (meaning you don’t go out of your way to puncture it). Warranty is limited to 10 years because they know you will have foot traffic.

      Here is how deck-shield should be installed:


      DeckShield should only be installed over DensDeck or similar, and must be fully adhered (glued) – no screws, except for along the perimeter.

      Here is DensDeck installation – note joints are “plastered” so that membrane would be as smooth as possible:


      And here you can see it in HD quality – welding post flashing:



      Now I know you got a quote from an IB Installer, but because he specified 1/2″ ISO over leaking/rotter Mod-Bit, I would not use them. Instead contact IB roofs for other certified contractors in the area.

      PS – with many other membrane products (TPO/PVC/EPDM) your warranty is null and void if manufacturer finds out there is “foot traffic” …

      PS2 – ISO brand has no difference – it’s pretty much same product, no matter who manufactured it (unless you go for super high density). The only purpose of ISO is to provide thermal insulation and ability to fully adhere membrane to it (that’s what fiberglass mat is for). Brand does not matter here.

      Reply
  11. Carrie

    Curious about the ability of TPO to stand up to tremendous snow load. There has been discussion about UV, but not the opposite, cold and snow? We are talking about 3-4 feet of standing snow for 6-8 months.

    Reply
    1. Leo - Roofer Post author

      Carrie, I believe most TPO brands should be find with standing snow, assuming the following:

      1) Seams are properly welded, so the roof would not leak under snow (there will be melting down below, between snow and roof.

      2) This is obvious, but roof structure must be able to support this type of snow load. I mention this because say in New Hampshire where lots of snow is common, roofs often collapse and roofers always have work in the winter, removing snow. Snow removal costs money and dumb roofers often damage roofs in the process … either by ignorance/stupidity or on purpose (to make work for later).

      Otherwise I don’t see big issues with gold weather… but you should research a specific brand that you are considering

      Good luck, Leo

      Reply

Leave a Reply

Your email address will not be published. Required fields are marked *