Flat Roofing Tapered Insulation Questions (from an email conversation with a customer)

This post is actually an email conversation with a customer, regarding Tapered Insulation and our flat roof installation in Cambridge, MA done in the summer of 2010. This email conversation is posted as is with the customer’s permission – the only editing on this post was done to remove any personal information, and spelling :). I thought this would be helpful to our readers, who are interested in tapered insulation and/or have ponding water problems with their flat roofs.

Here is the original roof video, so you have a better idea about this roof:

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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

Flat Roof Installation in Cambridge, MA

Image of Flat Roof in Cambridge MA

We installed this flat roof near Harvard Square in Cambridge, Massachusetts in the summer of 2010. The installation consisted of four separate roof sections on different levels of this house, which at the time was undergoing major renovations inside and out, including total new insulation in walls and between roof rafters, a new heating system with radiant floor heat, new energy efficient windows, and a new IB PVC flat roof (which we installed of course).

The old rubber roof was leaking and we had to remove it, including the wet roof insulation. We installed a new 50-mil white IB Flat Roof, with 4 inches of tapered insulation (4 inches at the highest point and 1 inch at the lowest level). The tapered insulation system was utilized to eliminate ponding water on the two bigger sections of the roof. At the deepest point, there was as much as 2 inches of ponding water, and a puddle with at least 12 feet diameter. This ponding water caused both roof leaks and the roof rafters settlement.

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PVC Roof Repair – Trocal and Sarnafil PVC Roofs Repaired With IB Roofing Material

Update – Oct 26, 2011: Exactly 2 years after the initial Sarnafil PVC Roof repair (read details below) I went back to that roof. This time, there were 17 new holes in the roof. I repaired it once again with IB PVC flat roofing material. Check out the full review of this latest .

Update 2: a Trocal roof repair also reviewed below – a section of that roof has completely shattered over the past winter, and we had replaced it with an IB PVC Flat Roof in the spring of 2011.

Check out the video of this new PVC Roof repair:

Original PVC Roof repair article

PVC roofing is one of the longest lasting flat roof membrane systems, and most PVC roofs installed, will last in excess of 25-30 years. PVC roofing utilizes Hot-Air welding of the seams, which allows the roof to remain watertight for many years, as there is no adhesive to fail ( as is the case with EPDM rubber roofing ). Still, even PVC roofs can leak. Sometimes because of poor installation, and sometimes because of physical damage to the roofing membrane. You may have heard about the Trocal PVC roof failures, which was the only major case of PVC roof failures (below we will explain how Trocal roofs failed).

In this article we will discuss and demonstrate the PVC roof leaks and repair procedure, based on two recent repairs we have done. First, please note that even if your PVC roof leaks – you should not be too worried – PVC roofs are rather easy to repair, and you will rarely need to replace your entire roof.

Trocal PVC Roof Repair – West Hartford, CT – Winter, 2010

As promised – a quick look into why Trocal PVC roofs failed on a massive scale, forcing the company to be sold to another large roofing materials manufacturer.

Image of shattered Trocal PVC roof

Trocal PVC roofing was one of the first commercially available PVC roofs in the US, and they worked great at first. But they had one major drawback – they were unreinforced (today, most PVC membranes are reinforced with polyester scrim sitting between the top and bottom ply of the membrane). When the ambient temperatures were below freezing, a Trocal roof could crack or shatter if you simply stepped on it. Later, all PVC manufacturers switched to reinforced membrane, and some would add special chemicals to increase the elasticity of the membrane. Today, unreinforced PVC membrane is used only for flashing accessories such as inside / outside corners, pipe flashing, etc.

Repair of a Trocal PVC Roof

Image of Trocal PVC Roof Repair

This Trocal roof sustained damage from a falling tree branch in December of 2009, and cracked along the edge. Although the roof was over 20 years old, it was still fully weldable and we were able to repair it with a new IB PVC roofing membrane in Jan. 2010. We removed the damaged section of the roof, cleaned the surface with MEK solution, installed new PVC coated IB Drip Edge metal, and welded a 50-mil white IB roofing membrane. The repair was performed in a 25 degrees outside temperature, so we had to take special care not to damage the rest of the original roof.
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NERCA Roofing Convention in Boston, MA

Last week, Boston was a host to hordes of roofing sales people, roof manufacturers’ reps and local roofing contractors from all over Massachusetts and New England. It was the NERCA (North East Roofing Contractors Association) annual convention, where most roofing materials, tools and equipment manufacturers were present, promoting their new products and services.

Boston MA a roofing convention

After being to a few of these shows already, I have found that they don’t get any more exciting, but it’s always nice that NERCA sets up up open bars with semi-decent wine, and cheese / crackers / fresh veggies & berries tables. I think that for roof sales professionals, these roofing conventions have become a boring necessity, as all they do is schmooze with each other and talk about competition. As for me and other roofing contractors, we can always find some new and exciting roofing materials, tools, equipment and services, such as infra-red roof scanners, roof lifts, a hydraulic-powered dumpster, which can be lifted to the roof level to speed up roof tear-off and clean up process.
As a Flat Roof contractor we were there supporting IB Roofs, which had a booth there, and I got to meet IB’s new Regional Manager, Dana Spurgeon, as well as IB’s local reps in Massachusetts – Jerry Lang and Kevin Laprte (whom I already know of course).

Roofing Equipment Presented at the Show

Besides the obvious and now ritualistic visit to the IB Roofs stand, I wanted to find as many cool, interesting and innovative roofing products at this show, and quickly wondered off, to explore the unknown. My first find was an excellent new automatic hot-air welder by Leister – the new Varimat V2.
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TPO Roofing – Is it Good Or Bad For the Roofing Industry And Building Owners?

Recently, the MRCA (Midwest Roofing Contractors Association) issued a warning bulletin regarding TPO roof failures caused by the sun’s UV rays. You can read more about it in our original TPO Roofing page, as well as my commentary on this bulletin.

At the same time, major roofing distributors are shamelessly pushing TPO into the market and onto the roofing contractors without much regard for home and building owners. Bear in mind that because of low prices and “same cool roof” and “welded seams” qualities as PVC roofing has, TPO is now the fastest growing commercial roofing product.

TPO Roofing Product for Residential Contractors

Here is a good example – pictures below will show you “manufacturer’s” stand showing a TPO roof designed for residential roofing contractors.

Why residential roofing contractors? Well, the way I was told, these are the roofers who can’t afford to spend $12,000 on hot-air welding equipment, so the roof manufacturer created a system that would allow these guys to jump on the TPO band-wagon.

(The TPO stand above, is displaying outside corner flashing, inside corner flashing, pipe boot, and drip-edge details. When I asked about the caulking along the seams, i was told it’s not caulking. It’s seam tape 🙂 )

Here comes the best part! This TPO roof system is put together with … no, not hot air. Seams are primed and a seam tape is used to seal overlaps! 😀 But, it gets better – since there is no uncured flashing material in the TPO world, and these “shingle-bangers” don’t have Liesters (hot air welders) nor do they want to buy them, since the cheapest one – a hand welder – is $450 before tax. So, this manufacturer uses white EPDM uncured flashing for all detail work such as inside / outside corners, posts, curbs (skylights, chimneys, roof hatches, HVAC equipment, etc.). EPDM rubber on TPO – really?
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Massachusetts Roofing – Recent Flat and Metal Roofs Installed in MA

Update – Dec. 12, 2010 – recently we’ve uploaded a gallery of many metal and flat roofs that we’ve installed in Massachusetts, Connecticut and Rhode Island – see the roofing jobs gallery. All roofs mentioned below are listed on the roof gallery page, with references to job profiles, and before / after pictures.

Before we go into job reviews, here are a few additional articles you may find useful, when choosing a roof product for your home and a contractor to install it:

How to prevent Ice Dams – a comprehensive guide focused on the rout cause of Ice dams, which is usually a combination of poor ventilation and inadequate insulation in the attic space or between roof rafters. This guide will help homeowners minimize heat leaks in the attic, improve ventilation and eliminate the effects of ice dam leaks by installing a Metal Roof or an IB low-slope roofing membrane.

Low-slope roofs – Overview of the common problems associated with low slope residential roofs, such as shed dormers or roofs on most cape-style homes located in the northern MA. Common issues with such roofs include rotten roof decking / rafters and Ice-dams. Since these roofs are prone to Ice dam leaks, most of the rot damage is an effect of ice dams. Although many roofing contractors will insist that using Ice and Water shield will do the trick, our experience shows that most of the time I&W fails to protect the roof even if the entire roof deck is covered in Ice and Water. Therefore, we believe that the best solution for permanent protection of low-slope roofs and eliminating ice dams is to install a metal roof or an IB flat roofing membrane in conjunction with solving ventilation/insulation issues described in the article above.

Roofs we installed in Massachusetts:

Low slope shed dormer roof in Westminster, MA

Leaking low-slope roof on a shed dormer in Westminster, MA

We installed this roof in early May of 2009. The house is located in a heavily wooded area of central Mass, just north of Mount Wachusett. Westminster, MA is located along Rt. 2, and not very far from the New Hampshire border. These areas get major snowfall in the winter, together with colder temperatures than those in Boston. Consequently, ice dams become a major problem in Westminster, even for high slope roofs. Low slope roofs, such as the one we replaced there, are very likely to have ice dam leaks and other problems such as a rotten roof deck, wet insulation, and mold.

The roof has been leaking for some time around the chimney in the center of the roof and was patched many times with tar, but rather unsuccessfully. Also, due to Ice Dams and roof leaks caused by the ice formation along the roof eaves, the homeowner installed heating cables to stop the Ice dam leaks. These did not help either, and after one more unsuccessful roof repair, the homeowner decided to get an IB roof installed.

Flat roofing Westminster, MA

The homeowner and his cousin, who is a roofer in NH, did the roof tear-off and replaced all rotten plywood decking, to reduce the cost of installation, while we installed the roof itself, insulation, chimney flashing, ridge vent and snow guards (snow retention system).

Note – before we installed the IB membrane, the homeowner’s main concern was to get ice and snow off the roof. After the IB system was installed, our concern was that due to the roof’s pitch, which was about 3 in 12″, the snow and Ice would just slide off the roof in a large pile, crushing down onto the deck and perch bellow it. Also, there was a grill on the deck, which was not removable, since it was tied to a gas line.

IB flat roof westminster massachusetts

The chimney flashing, which may seem like a quick job, actually took about 6-7 hours to properly flash. The reason it turned out to be so time consuming, is that it is located in the center and separates the ridge vent, as well as creeping onto another side of the roof. Due to its position, size and the way an IB roof is installed, it not only took long to work around, but also slowed down the rest of installation. Because the ridge vent butts into the chimney, we had to make sure that not only the ridge vent was raised an inch off the roof level to prevent the wind-driven rain from leaking into the house, but also that it was completely tied to the roof, and flashed up the chimney. Once the chimney flashing was installed, counter flashing reglet had to be installed as well.

Chimney flashing on a flat roof in Wetminster, MA

All in all it took us 3 days to install this roof, though the 3rd day was rather short. What really slowed us down, was the first heat wave of that spring and an overwhelming amount of bugs / flies / mosquitoes in this wooded / swampy area of central Mass.

Roofing membrane used: 50 mil mechanically attached IB PVC flat roofing system.

Insulation used: 1/2″ fan-fold Styrofoam insulation with clear plastic / metal facing.

Total roof square footage: Approximately 500 sq. ft.

Standing seam metal roof in Wayland, MA

Right after the roof in Westminster was installed, we started getting ready for a big metal roofing project, in Wayland, MA. On this job, we installed a .032 Aluminum standing seam metal roof in 1 3/4″ snap lock profile with 16″ wide pan and stiffening ribs. This roof took about two weeks to install, including tear-off of old asphalt shingles, siding removal, replacement of rotten wood replacement, delays with material shipments and the wrong type of flashing being delivered.

Standing Seam metal roof in Wayland, MA

Actually one of the delays happened because our supplier ran out of Grey aluminum coil after 80 % of roofing panels were rolled out of their mobile standing seam roll-forming machine, which was based in Manchester, NH. As the supplier received more aluminum coil 3 days later, he sent a different truck, from New London, CT. As that truck arrived and rolled off the first test panel, just out of curiosity I decided to compare the first batch to the second one. It turned out that the machine on the New London truck was set up to be 1/8″ wider than the Manchester truck. This, over the course of 23 panels gave us an extra 3″ of panel, which converted to two extra panels – 1 1/2″ wide – on either side of the rear roof section and exactly 23 panels on the front. We had to send the truck back and wait for the Manchester, NH truck to deliver and roll out the same coil. Even the guys working for the supplier were not aware of this mismatch between the two machines.

F-Rail rib-mounted snow retention system from Berger snow-guards.
F-Rail rib-mounted snow retention system from Berger snow-guards.

Finally, the Manchester truck delivered the right-width panels and we were able to finish the job without any more delays. The homeowner,Glenn, was also very concerned with snow and ice falling off the roof and damaging the gutters bellow, so we installed a commercial-grade double rail snow retention system to eliminate the possibility of snow falls from the roof.

We already posted a full review of this roof installation on our blog, a few months back, so if you want to know more details, read the standing seam metal roof in Wayland, MA job profile.

IB PVC Roof installation in Boston, MA

leaking rubber roof boston ma

In August of 2009, we completed a rather small, but very tricky and complicated flat roof installation in Boston, on one of the traditional Boston-style homes/buildings, which you can see all along Mass. ave, Comm. ave, as well as Blue Hill avenue, on which this house is located. It was originally an EPDM rubber roof, which had over 50 percent of seams separated due to adhesive failure. The two-tower wood design made this roof much more difficult to repair and our client, Jim, chose to eliminate the hassles of frequent roof repairs and decided to have an 80-mil IB roof installed.

Although this should have been a pretty much straight-forward roof replacement, with rubber tear-off performed first and a new IB roof installed, I sensed that it will not be an easy job. Until we opened up the roof I could not say for sure what obstacles we were going to face, but once we did remove the rubber, we found that the entire length of the masonry parapet wall was damaged by water and poor quality of brick mortar. We also found that we would have to rebuild the parapet walls as much as 4 layers of brick deep.

Rubber roofing Massachusetts

Because I chose a careful approach to the rubber removal, by only pulling back the rubber membrane off the parapet wall, and not cutting it, we were able to do the entire brick repair work and roof preparation, while having the roof watertight each night with the original rubber membrane.

Once all brick repair was complete and mortar had sufficient time to cure, we installed a 2×8 pressure treated perimeter wood nailer to which IB wall flashing and drip edge would be attached. Only on the last day did we remove the whole rubber roof, installed new insulation and laid down the new, mechanically attached IB PVC flat roofing membrane.


We had to come back one more time to install the new gutter and downspouts, IB two-way membrane vents and 9″ IB attic vents over specially cut holes in the roof deck. These attic vents were installed to vent out the moisture that accumulated in the small attic space when the old rubber roof was leaking. Once in place,these over-sized vents will eventually dry out the attic and prevent any future mold growth.

Now Jim can enjoy his watertight roof and get sun baths sitting in his beach chair on the roof of his home, and not worry about damage to the membrane – he chose a very durable, commercial grade 80-mil IB roof. He will also enjoy a cooler home, due to the IB’s cool roofing features.

rubber roofing boston ma

You can read the complete job profile about this Flat roof in Boston, MA on our Cool Roofing Blog.

Flat roof in Framingham, MA

One of the more recent flat roofing jobs was in Framingham, MA, where we installed an IB roof on yet another shed dormer roof for Ed Kelly – a high-end remodeling contractor out of Northborough, MA. The builder had his crew remove old asphalt shingles off this roof and replace most of the old decking with new 3/4" plywood. We were there to install just the membrane and flash it 2 feet up the sloped roof.

Flat roofing Framingham, MA

During my conversation with Ed (the builder), he told me me why he chose the more expensive IB roof over a cheaper rubber EPDM membrane. His main reason was the IB’s hot-air welded seams, and hassle free roof performance. Before, Ed used rubber roofs on a few of his projects, and all but one of them leaked due to problems with seams, and required expensive rubber roof repair. Ed decided to end his flat roofing nightmares and constant leaks, and chose an IB roof.

IB flat roofing.

The entire job took us one day to complete. The roof was prepared when we arrived to the job site in the morning, and before dark, we packed our tools and were ready to leave, as the installation was all done. The roofing crew which did the tear off and deck replacement was putting the new asphalt shingles and aluminum fascia trim back on, as we were driving away.

Roofing material:50 mil white IB roof, mechanically attached.

Insulation: 1/2″ fan-fold Styrofoam.

Total roof size: Approximately 450 sq. ft.

Flat roof deck in Wellesley, MA

Just before the Framingham flat roof job described above, we did another job for Ed – an 80 mil IB roof that would be a water-proofing membraneroof deck over a garage being built as an addition to an already huge home in a very secluded area of Wellesley.
roof deck wellesley ma

Once again, a complete job profile for this roof deck is already on our blog, so there is no point to rewrite it here – read the Wellesley, MA  flat roof deck installation overview.

Solar flat roof in Medford, MA

This job, was actually sponsored by Cool Flat Roof (us) and IB Roof Systems, as it was a non-profit project, competing in the 2009 Solar Decathlon competition, sponsored by the US DOE. We installed an IB roof on a Boston solar home with some help from the project volunteers and Architecture students from BAC and Tufts.

Solar flat roof of  Boston solar home in Medford, MA

Once again, we have a complete coverage of the installation of the IB flat roof and the Solar PV panels on this roof – Solar roof installation in Boston, MA.

Low slope shed dormer roof in Hingham, MA

Yet another shed dormer roof and also with major ice dams problems and leaks. This roof was just a year old when we removed the old asphalt shingles, and installed a new 50 mil IB traditions roof with an asphalt shingles pattern printed onto an IB white roofing membrane. This roof was completely covered with Ice & water shield, which failed miserably and forced the homeowner to climb up the slippery ladder all winter long, sometimes two times a day, to brake off the ice along the roof edge.

Shed dormer roof in Hingham, MA - a quiet town on Massachusetts South Shore.

The homeowner, Paul, tried everything from sodium-filled socks above the skylights to heating cables – nothing seemed to help, as with a lack of proper ventilation and inherent limitations of asphalt shingles, his roof was still leaking, as it faced north, and the sun never shined over it in the winter.

Paul wanted a permanent solution to stop leaks and not a single contractor that Paul contacted could explain to him how they would stop the leaks or promise that their roof will work. Some even offered to install asphalt shingles with Ice & Water shield – Really? Paul already had shingles with Ice and Water and it was not working.

IB flat roofing membrane being installed on a low-slope roof in Hingham, MA

Initially, Paul contacted us about getting a metal roof installed on his house, but after examining the roof, I suggested he install an IB roof instead, and residential flat roofing solution form IB  – Traditions Classic seemed to be the best option as it combined all the benefits of an IB roof with the classic look of architectural asphalt shingles printed onto the membrane. After a little decision making, Paul and his wife chose to go with a seamless one piece IB roof. In this case, there would be zero possibility of ice dam leaks.

All skylights now have seamless 1-piece flashing welded to the roof, and the ridge vent is raised by an inch above the roof level to prevent wind driven water from penetrating the roof.

All skylights now have seamless 1-piece plashing whelded to the roof, and the rodge vent is raise by an inch above the roof level to prevent wind driven water from penetrating the roof.

Now that Paul has a new IB Traditions Membrane, which is in effect a seamless, one piece blanket over the entire roof, he and his wife won’t have to worry about leaks and breaking ice off the roof any more.

Getting an IB Membrane or a Metal Roof installed on your home in Massachusetts:

If your roof is leaking or you have Ice dams, and are tired of fighting with the ice, using heat cables, sodium-filled socks, raking your roof, and risking to fall off a ladder, you need to contact the low-slope roofing experts ( us :). Request a free roofing price quote and schedule a roof inspection / estimate. You can also use our online roofing calculator to estimate your roof replacement cost and compare prices of IB PVC membrane to Rubber roofing, Modified bitumen / Tar and gravel roofs.

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” – http://www.wsrca.com/bookstore/index.htm.

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]

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!