Energy Efficiency

What makes PVC the Best Single-Ply Roofing Membrane for Flat and Low -sloped Roofs

Senior project written by Riess Stanley
Nov 4, 2010

With economic strife on the rise, it has now become necessary to seek out ways to save money, as well as to find ways to “stay green”, and to do what you can to help the environment. Unfortunately, accomplishing both at the same time seems to be very difficult. Believe it or not, there is a smart, fairly simple, and very efficient way to succeed in these two areas in a way not often looked upon as a money saver, but rather a necessary and costly project when it doesn’t need to be; the roof. When you really get down to it, the roof is either costing too much, or saving plenty.

First off, if a building with a flat or low-sloped pitch was to have a black tar roof, it would be taking more money than one would realize. In warm weather, the black roof will absorb so much heat that an abundance of energy and money would need to be invested into cooling down the building. Moreover, all that heat beating down on the roof will make it crack, which in turn will cause it to leak once the rainy weather begins. This defeats the entire purpose of a roof. So, what is a low cost alternative for a black tar roof, that can keep the roof cool during summer months and can keep out the rain? The answer; PVC (Polyvinyl Chloride) single-ply membrane. Continue reading

Green Roofing Contractors – How Are We Different From Other Roofers?

The term “green” has become very popular during the last decade and consequently overused, misused and abused. Anything and everything can be called “green” today. To make money and to attract environmentally-conscious customers, people will call themselves and their products “green”, even when it is just a blatant lie to confuse uneducated consumers. Being a roofing contractor, I will concentrate on roofing products and services. For example, many asphalt shingles manufacturers now offer “cool” and “green”  shingle products – to me it’s just a shameless tactic to sell the same NOT-GREEN crap that is painted A different color (usually some shade of white). Excuse me, but asphalts shingles are not green, period! TheY are made with asphalt, can’t be recycled and end up in landfills in 10-15 years.

Since the term green is very vague and can be interpreted in many ways, I’ll offer my vision of “green” – a green roofing contractor to be exact, which describes the way I think and try to operate our roofing business. I want to mention that when I say “green roofing contractor”, it has nothing to do with with a roofing contractor installing green roofs or roof-top gardens. To me a contractor installing roof-top vegetation is a highly-specialized landscaping company, but not a roofing contractor (unless they also install the actual flat roofing membrane to waterproof the building).

Quick navigation in this article:
What is a “green” roofing contractor and how one is different from regular roofing companies.
Learn about green benefits of Metal Roofing and IB Flat Roof

What is a “green” roofing contractor?

In my mind a green roofing contractor is a company that works hard to help protect environment and reduce its energy consumption and green-house gas production or carbon footprint. Sure, almost any company will have a carbon-footprint as it’s nearly impossible to be carbon-neutral, but there are many ways to achieve a much lower carbon footprint. Continue reading

Single-ply Flat Roofing Systems: PVC and TPO

If you are a building owner, facility manager or even a homeowner with a flat roof that leaks, and you are interested in or got a bid from a contractor to install a new flat roofing system called TPO (Thermoplastic olefin), this is a must-read article for you, because you will not find this information anywhere else.

From The Editor: – this post has 50+ VERY interesting comments from “both sides of the aisle” so to speak. We highly recommend you read these comments, after the post.

Foreword: TPO is a hot-air welded thermoplastic single-ply roofing membrane produced by numerous manufacturers. TPO was created to be better than EPDM Rubber roofing and cheaper than PVC roofs, while it would still provide all the benefits of hot-air welded seams. It was a good plan, and now TPO membrane covers billions of square feet of roofs and represents a multi-billion dollar roofing market, but there are some problems…

In it’s fairly short life (about 15-16 years) TPO went through at least 2 generations. 1st generation of TPO roofs began to fail in the late 1990’s and early 2000’s. Now, some manufacturers are on their 3rd generation (or major reformulation) of their TPO products. At the same time, TPO’s main rival – PVC roofing membrane such as IB Flat Roof, has not changed its formula in over 30 years.

The video clip above below a brand new TPO roof burning on a roof of a new office building that was built in Salt Lake City, and filmed by the Fireman crew.

Why you should not get a TPO roof – TPO roof on fire video

Whether you are a customer looking for a new flat roof or a roofing contractor, I recommend that you to do some serious research on TPO before investing in it. This will serve your own benefit.

To start, you may want to check out the WSRCA (Western States Roofing Contractors Association)  “TPO roof study” –

WSRCA’s test roofs in Las Vegas, NV, Anchorage, AK, San Antonio, TX, and Seattle, WA demonstrate the product service life in diverse climates throughout the western United States. All have weathered past the four year mark, and the results are now published.

The problem is that for some reason they pulled off 2007, there is still no 2008 edition and only a 2 year old report from 2006 is available. But here is the “rumor” from trusted sources:

TPO roofs in the above study lose minimum of 1 mil of thickness per year and some TPOs lose as much as two mil per year (in 10 years that will be 20 mil – imagine that on a 45 mil membrane). The average top ply thickness is 15 mil – some are 12. Once you are down to the scrim, the roof is gone, and the UV will eat the scrim and bottom ply.

Also, there are problems with seam failures, premature curing, cracks along the seams, etc. These are TPOs made in 2001-2002 (second generation) Supposedly there is no 3rd gen. going into production, and I suspect that the reason for the 2007/2008 edition of this book not being available is because manufacturers pressured WSRCA to pull those off. I could swear that I saw an ’07 edition available on sale in January ’09, and now its not even listed.

Aside from the above, most TPOs and maybe some PVCs (to cut costs) come with a wicking scrim, so you need to do something about the edge of the weld – that is like welding twice, and there is still lots of room for error, and once the water gets to the scrim, it will delaminate the membrane… I don’t need to explain the consequences.

So, the bottom line – do you want your customers to have a 2nd/3rd gen. of repeatedly failing roof technology and put your reputation on the line for a gimmick created by greedy roofing manufacturers, who are looking for ways to reduce costs at the expense of quality (putting cheap fillers into membrane to create nominal thickness)? What is the difference between 45 and 60 mil TPO if weathering surface is 12-15 mil? Just a thicker bottom play that is made of junk in a first place.

Another thing that amazes me about TPO is the peel-n-stick seams. WHY?… The whole point of thermoplastic roofs (PVC & TPO) is the hot-air welded seam… EPDM rubber roof can be peel and stick… but TPO? All it does, is attract hacks into thermoplastic roofing market. Those who do not care about quality install, fly-by-night dudes, etc. I mean, if you as a roofing contractor go and spend $10-20K on the hot-air welding equipment you probably won’t disappear tomorrow, as you need to pay for that equipment and make some money on top of that. You as a roofing contractor are probably in it for the long run…

Instead of conclusion:

As I mentioned in the beginning of this article, the idea of a TPO roof is great. A cheap, naturally cool, long lasting flat roof system featuring hot-air welded seams is something of an ideal for the roofing industry to strive toward. However, the “cheap” part in TPO is why all these roof failures occurred, and will be happening on a wide scale in the near future. TPO’s problem is not the faulty design. In Europe, TPO has been around for decades and is considered to be a very good flat roofing system.

However, here in the US, roofing manufacturers put the bottom line in their accounting books above product quality and interest of their clients by manufacturing their TPO membrane using primarily cheap fillers and low quality wicking scrim, without proper testing or acquiring UL certifications. In the end, roof owners and to some degree roofing contractors become victims of corporate greed and irresponsible business practices.[PSGallery=1ondfvgxk]

Is Solar for you? Comprehensive Solar PV System Design Guide

Electricity in the 21st century.

Do you know how your electricity is generated? For a long time I kind of knew, but was too lazy to actually ask my father, who is a physicist, what exactly is going on in the power plant. Now it boggles my mind to live with the fact that in our modern time when an all-inclusive communication and Internet devices (iPhone, BlackBerry, etc.) is smaller than a deck of cards, we still use 19th century technology and basic principles to generate our electricity. Once you actually give this idea a thought, it becomes a shocking notion that our best minds have not been able to design a better way to generate electrical power than to burn coal and natural gas – two most commonly used sources of energy to create electricity.

Just in case you were wondering, coal or gas is BURNED to heat up water, which then becomes hot steam and drives the turbines. This is a basic principle and the actual process is more complicated, but even the “sophisticated” nuclear power plants work in a similar manner.

Note: I did know that electricity can be generated in the old fashioned way, but I actually thought that there was some kind of a mechanism to directly convert energy stored in gas / coal / oil directly “into” electricity, instead of emulating the old steam-engine – oops… It is a shame that our 21st century society is still burning fossil fuels to make the turbine spin.

Aside from the fact that we get our electricity the same way as before WW I, natural gas, oil and especially coal are extremely dirty fuels, emitting dangerous pollutants, which affect our environment in such a drastic way that just a couple of generations from today, our children may not be able to enjoy the outdoors the same way we can today. I won’t even start talking about climate change and global warming. On top of everything mentioned above, humanity is quickly approaching a worldwide energy crisis. Our oil reserves are getting depleted, and if you believe in “Peak Oil” theory, we are about to approach the peak of the curve, which means that oil will continue to become more scarce and prices will keep on rising.

Although coal is very abundant, it is also becoming more expensive to mine, and delivery once again involves burning petroleum based fuels, creating more and more pollution. It is obvious to most intelligent people (except those heavily invested in oil, coal, cars, etc.) that we need a clean, renewable source of energy. Despite what may seem like rhetoric about renewables, I do honestly believe that this is the way we will power our world in the future. However, the renewable energy must be affordable and/or competitive with current sources of energy.

Why Solar?

So what is the answer – what is a modern and clean way to generate electricity? Well, there are a few, and the most popular ones are Wind and Solar. My personal favorite is Solar, and here is why.

Wind Turbines require lots of open space and lots of (you guessed it) wind to work effectively. Although wind is a great source of renewable energy, and unlike solar can work at night, it is not “customizable” or adaptable for the urban environment. There is just not enough space or wind in the city.

Solar, on the other hand, works just as well in city as in the countryside. All you need is southern exposure with none or minimal shading. Solar can be installed on a roof of a skyscraper, on the ground or even on a roof of a car. Solar is also a scalable system, and you can add or remove PV panels and/or inverters at any time. The bottom line is that solar photovoltaic power generation is much more practical, and can be implemented almost anywhere that power is needed. Besides that, both ways of getting “free” electric power from renewable sources are great.

Eco-friendly Cool Roofing

Cool Roofs provide financial and environmental benefits and long-lasting protection from the weather.

Roofing represents only 3% of construction costs. Yet, many builders, architects / specifiers, roofing contractors and even home / building owners look to reduce their total construction and/or renovation costs, and all too often they find these savings in roofing. This cost cutting comes not only at the expense of installation quality, but also with the use of inefficient roofing materials. Two most common roofing choices are asphalt shingles for pitched roofs and EPDM ‘rubber’ for flat roofs. The former is made directly from oil, and the latter is made with oil by-products and other chemicals.

Cool Roofing

Cool Roofing

Are Cool Roofs for everyone?

In theory, every roof should be cool. If that was the case, our nation would greatly decrease its energy dependence and consumption. We would also improve our environment and air quality, and use less electricity to cool our homes and buildings. Bear in mind that over 50% of our electricity comes from coal-burning power plants and coal is the dirtiest source of energy; it pollutes air with, sulfur, lead, arsenic, CO2 and other harmful substances and greenhouse gases.

However, many people would argue that cool roofs are only for Sun-belt states, and that black roofs are better for northern states. This is completely wrong. Lets review the differences of Cool (white) roofs and black roofs in terms of energy savings and heat gain in the summer vs. heat loss in the winter.

First of all, let me point out that in the winter, heat does not escape the building (unless you open your windows), but rather cold air enters the building and lowers the inside temperature. With this in mind, lets compare the energy cost advantage of a black roof in the winter and a white roof in the summer.

Energy Costs Calculation

Roof heat gait chart: IB vs black surface roofs

Heat gain through the roofing surface: As you can see from the chart above, on an 85 degree F day, an IB cool white roof will only gain 6 degrees or about 8%, whereas a black surface roof, such as EPDM rubber or rolled asphalt or a tar roof will gain 87 degrees (!) or more than double in temperature, for a total of 172 F. If you get down on your knees, you will actually get skin burns. Imagine all this heat entering inside your home or place of business…

For comparison purposes we will use a White IB PVC roof and a regular EPDM black rubber roof. We will use DOE Cool Roof Calculator and with following parameters:

Gas will be used as a source of heat, but since gas rates differ from city to city, we will convert the BTU value of 1 gallon of oil to that of 1 therm of natural gas. The oil price used in this comparison is $2.39 per gallon, which is the average here in Massachusetts for oil customers with delivery contract as of January 8, 2009. Please note that the price of 1 barrel of Oil today is $41.89.

Calculation metrics:

  • Insulation R-Value: 6, 13 and 20 (6 is the average for existing residential building where we replace a flat roof)
  • Solar Reflectance: 85 for IB Roof and 6 for Black EPDM. Although IB’s reflectance is 87% the calculator will not let us use more than 85, and since with dust accumulation on the roof reflectance drops, it is safe to use this number.
  • Infrared (thermal) Emittance: 88 for IB Roof and 86 for Black EPDM.

Scenario 1 – Boston, MA.

Cost of electricity in the Metro Boston area is approximately $0.22 per kWh. The cost of heating the building we get by multiplying price of 1 gallon of oil by 0.71  = price of “1 therm of heating oil” – $1.70 / therm. Note, that this is not the price of one therm of natural gas, but rather a BTU conversion from oil to natural gas. I use oil as it is the most common source of heat in the north east and in New England in particular.

Scenario 2 – Los Angeles, CA.

I will assume the energy price in CA, as I do not live there. For electricity rates I will use 30 cents per kWh. This assumes peak rate (when most people actually use their air-conditioners) and all the surcharges, delivery charges, etc. This is the total cost per kWh.

Since gas prices in CA right now are just a bit higher as compared to Mass. we will use $1.80 as the price of therm of heating oil. Bear in mind that in California, they rarely use heating and it is mostly natural gas or electricity or propane for remote homes.

Other calculation metrics:

  • AC efficiency: We use an average of 2.0
  • Heating System efficiency: We use an average of 0.7 or 70%. My brand new Burnham closed loop hot-water radiator system is 86% efficient. The older heating system it replaced was about 50% efficient if not less. Also note that this is the burner efficiency and not the total system efficiency. Total system efficiency is greatly dependent on how well your house is insulated, the type of windows you have and the type of heat delivery you use: radiant, air ducts, steam or copper pipes with hot water circulating through the system.

Results – Net Savings per 1 square foot of flat roof area per year: Boston:

  • With 6-r insulation Net saving is $0.079 or almost 8 cents.
  • With 13-r insulation Net saving is $0.037 or almost 4 cents.
  • With 20-r insulation Net saving is $0.023 or almost 2.5 cents.

Los Angeles:

  • With 6-r insulation Net saving is $0.217 or almost 22 cents.
  • With 13-r insulation Net saving is $0.1 or 10 cents.
  • With 20-r insulation Net saving is $0.062 or almost 6.5 cents.

Let us now assume that you home is 2000 sq. ft. and has 6-r insulation value of the roof. In Boston, MA you would save $160 per year in electricity alone if you replaced your existing black roof, such as epdm rubber or tar & gravel, with a cool IB roof. Also, add leak free performance of IB roofs, no more roof repairs and other costs associated with roof leaks. In Los Angeles, you would save $440 each year! Also add the Energy Star tax credit for cool roof installation of $500. This is an actual tax rebate, and it equals to an average of $1800 worth of tax deductions. Overall, I would say that Cool Roofs are much more efficient in the southern states where there is a lot more sunshine and almost no snow. But even here in New England, a cool roof is a very attractive choice for people who are looking to get long term savings, lifetime leak free performance and/or are worried about the environment.

Cool roofs vs. Black roofs


While asphalt shingle is the ‘de-facto champion’ of sloped roofing with its VERY low cost and severe price competition in both residential and commercial markets, when it comes to flat roofing, there are more choices. Old-timers will recommend a 3 to 5 ply Built-Up roof or a two-ply Modified Bitumen. With the abundance of these and other tar and asphalt roofs still in service, and some new roofs being installed (although each year there are fewer BUR, asphalt and bitumen roofs being installed, as the flat roofing industry is quickly transitioning toward single-ply roofing membranes), all of these roofs are destined to end up in our land-fills, as recycling programs for asphalt-based roofs are virtually non-existent. That is millions of tons and billions of square feet of oil waste going into the ground each year!

Another problem associated with the above-mentioned roofing materials is their color – most are black, which attracts and transfers tremendous amounts of solar heat into the building or a house. As a result, the air-conditioning system must work over-time to maintain a comfortable working and living environment. This causes overloads and power outages on electrical grids, increased cost of electricity, and as a result – higher electric bills.

To offset the above-mentioned high cost of electricity, many people choose to install a Solar PV roof system. This is especially true in California where $0.35 – 0.40 per kWh of electricity is a normal residential rate. We wholeheartedly support nation-wide deployment of small and large scale solar photovoltaic systems, but the first step, which many people should take before installing solar systems, is to reduce their average energy consumption. This is where Cool Roofs come in very handy.

Financial Benefits of Cool Roofs

1 – Energy savings of Cool Roofs

Cool roofs provide tremendous reduction in cooling cost by reflecting 85-90% of solar heat and keeping your residence or place of work cooler in the summer. This directly reduces your electricity costs. This also puts less strain on your HVAC equipment, which leads to less maintenance, reduced repair costs and longer life for the Air Conditioning units.

2 – Cool Roofs last longer and leak less than black roofs.

Cool Roofs generally outlast their counterparts by 50-100% and require much less maintenance and repairs than Rubber roofs, modified bitumen and tar / asphalt roofing systems.

For a flat roofing market, the two major players are PVC and TPO membranes. These are single-ply, thermoplastic roofs which are hot-air welded together to provide decades of leaks-free services. There are also acrylic and urethane cool roof coatings, which make existing black roofs cooler and increase their service life by 5-15 years.

Note: PVC and American-made TPO roofs are fundamentally different in terms of their chemical formulation and life expectancy, but both are considered cool roofs and ideally should last 20+ years. Learn more about the difference between PVC and TPO roofing.

While 40 years ago there was no real alternative to asphalt-based roofing materials in the US market, for over 30 years we have had cool roofs that are energy efficient, light weight and provide long-lasting protection with much flexibility to accommodate for any obstacle present on the roof. PVC Roofs were the first real cool roofs to hit the US commercial roofing market. Some US manufacturers of early PVC membranes (most notoriously Trocal) had problems with their product, such as membrane shattering in extremely cold temperatures. The problem was due to the membrane being non-reinforced with nylon scrim. All major PVC (and TPO) membranes on the market today feature reinforcing scrim.

IB PVC / CPA roofing feature a true Non-wicking scrim, which prevents the capillary water penetration between the two layers of the membrane. This is only one of many benefits of IB PVC Roofing which sets it apart from all other flat roofing systems.

3 – Cool Metal Roofs.

Residential metal roofing

Residential metal roofing

For large commercial / industrial applications, there is structural metal roofing, usually found on space metal buildings, aluminum reflective coatings, etc. Although these do not meet Cool Roof requirements, they still are more energy efficient than black rubber and asphalt-based roofs.

For residential and some commercial / retail / restaurant applications there are various styles of Architectural Metal Roofing. Usually coated with Kynar / Hylar high-performance coatings (paint) these roofs carry a Cool roof label and also greatly increase the energy efficiency of your entire home or building.

Even without a Kynar coating, metal roofs are always “cooler” than asphalt shingles. Since metals (especially aluminum) have a much lower thermal mass, they do not store heat, and cool off much faster than any asphalt based roof.

Environmental benefits of Cool Roofs:

IB Roofs as well as other Cool Roofing systems provide enormous benefits to the environment. From reduced CO2 pollutions to reduction of roofing material waste going into our landfills, the whole chain of benefits is too complicated to fit into a general theme of this article. Therefore, I will only list the basic environmental benefits here.

General benefits to the environment: Again, I’ll use IB PVC roof as the example, but most other cool roofs will “fit the bill”.

As a side note, I’ll mention that USA makes up about 5% of world’s population, yet we consume 25% of the world’s energy. It is also estimated that 30% of US energy consumption is just wasted. Therefore, we (Americans) waste 7.5% of the worlds entire energy.  And we wonder why gasoline / oil / electricity is so expensive….

  • PVC roofs last an average of 2 times longer than other flat roofing systems. PVC is extremely durable & versatile – therefore rarely needs replacement. When you hear that PVC is not recycled bear in mind that most Pvc-based products are still in service.
  • PVC roofs are 99% recyclable and will find use in other applications after they complete their life-cycle. PVC rarely ends up in our landfills, as it is cheaper to recycle it than to dispose of it. You will usually see it at landfill sites as a waterproofing liner that will prevent toxins and pollutants from entering the ground under large piles of junk and waste.
  • Although PVC roofs use fossil fuel as one of its basic components (natural gas – methane, to be exact), they also use chlorine as the 2nd major component – therefore PVC contains 50 % less fossil fuels than other plastics (such as TPO roofs) and  do not use and carbon / oil-based products in it. Therefore PVC is not directly dependent on foreign oil supply, unlike Epdm / Modified Bitumen / Asphalt / Other Thermoplastics and oil-based products.
  • Cool roof properties of PVC (and other cool roofing systems) reduce electricity usage of many commercial / industrial / residential buildings year after year. As a result, less pollution is emitted into the atmosphere. In fact, if all roofs in the US were cool, we would reduce our nation’s energy use by an average 10%, which is now just wasted!