Choosing a Black or White Reflective Low Slope (Flat Roof) Membrane
The Catalyst Article - White Roofs, Green Myth?
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| Huffington Post White Roof Article |
An article recently emerged in the Huffington Post (White Roofs, Green Myth?) written by a credible contributor (Samir Ibrahim, Director of Design Services and Project Reviews, Carlisle SynTec) that gives us (roofers) some additional confidence when communicating with building owners and home-owners about flat roof membrane choices in colder climates like Canada or Northern areas of the United States.
Carlisle Syntec is a considerable manufacturer of both black and white "cool roof" roofing membrane (Carlisle Syntec).
Marketing Noise Can Cause Market Confusion - Cool Roofing vs. Black Roof
The green roof or reflective environmental roofing movement has posed some challenge to roofers in Canadian and northern US markets as it applies to assisting customers with choices of low slope roofing membranes. Market pressures are pushing for "green" "reflective" "energy wise" "environmentally friendly" roofing choices - the marketing noise can be overwhelming for our customers wishing to sort through what is best for them. And as a result of this market changing "marketing noise" process, roofers have had some difficulty dealing with the issue of white or reflective roofing (in colder climates).
We are the ones after all walking and working with the roof itself on a daily basis and our opinion (or expression of observation in practical experience) does not always concur with the marketing noise. In other words, we see the result of a white roof membrane and its performance and life-cycle in colder climates.
We aren't scientists or engineers, just simple roofers that work with and install, repair, and maintain the roofs to protect the assets of our clients. But now even the science of reflective roofing and its green roofing advantages are being questioned...
Stanford University - "Urban 'heat island' effect is only a small contributor to global warming, and white roofs don't help to solve the problem, say Stanford researchers."
A White or Reflective "Cool" Roof May Have Its Place in the Market
Now, to be clear before any arrows start coming our way, white roofs (reflective roofing) does very specifically have its place potentially (such as in California) and additionally in northern climates it may even have some place perhaps if the right white roof is applied (for example) or in areas where there is an urban heat island effect like in Toronto - in downtown Toronto a reflective roof may very well have it's place - we suspect so, but we don't specifically know. See also Urban Heat Island effect on Wikipedia.
Black Roofing in Colder Climates Should be Considered
What we do know is that there are many reasons to very closely consider using a black roof membrane (such as Torch-On SBS with a black granule or grey cap sheet, EPDM, liquid rubber, and tar and gravel) in areas such as northern USA and most of Canada (more specifically in Northern BC, all of Alberta, Saskatchewan, Manitoba, many areas of Ontario and Eastern Canada, and the northern US states).
Unbiased Representation is Important When Considering Roof Membranes and a Contractor
Forget the fact that you need to choose a roofer that applies low slope roofing on a daily basis and not shingles, there are many other considerations.
General Roofing Systems applies all roofing materials for low slope roof structures... black, white, reflective, fluid, torch on, metal, spray foam (spf), mechanically fastened, ballasted, etc. Systems such as EPDM, TPO, PVC, SBS Modified, Torch On, Mopped BUR, Spray Foam, Fluid Applied Hot and Cold Rubberized Roofing, and on and on. In other words, we have no reason to be specifically motivated to one type of roof membrane - be it black or white or reflective or green except as it applies to the future performance and service-ability of the roof.
Our motivation is specifically toward service-ability and life-cycle. In other words, we know that if we install this or that roof in this or that area that this or that roof gives us more service work than that roof on average. And it is specifically in our interest to be sure that our service rate is as low as possible because we guarantee our workmanship on every roof for the life-time you own your property (see roof installation guarantee).
Top Three Concerns or Problems We Have Experienced With Reflective or White Roofs (Cool Roofing) in Colder Climates
The following is a top three listing of some of the issues or observation concerns we have specifically with white roofs or reflective roofing specifically in areas that we service (which are primarily colder climates and not in warmer climates such as California, Texas, or Florida for example). The top three problems with reflective roofs in colder climates below does not delve in depth with issues such as building energy efficiency with reflective roofs in colder climates and the like as those issues are for other articles.
Here are our top three list of reflective roof concerns:
1. Metal Roof Coatings - Metal roof coatings have in our experience in the areas we service failed to a great degree. We have never been confident in a reflective or white coating in colder climates. None are successful in our experience. They crack, peel, and flake and become useless in a few short years or less. In California we expect they work exceptionally well, but in colder climates they fail, fail, and fail.
More recently we have been using liquid applied rubber to metal roofs that we have seen much improvement with. We now have millions of square feet applied and they seem to perform very well. They expand up to 1000%, are from what we can tell UV stable, and all seems to be just as marketed. But the white coatings we have never found to work in cold climates on metal roofing systems. White roof coatings on metal roofs are also used over top of spf or spray foam applied to metal roofing - point 2 below covers this topic.
More recently we have been using liquid applied rubber to metal roofs that we have seen much improvement with. We now have millions of square feet applied and they seem to perform very well. They expand up to 1000%, are from what we can tell UV stable, and all seems to be just as marketed. But the white coatings we have never found to work in cold climates on metal roofing systems. White roof coatings on metal roofs are also used over top of spf or spray foam applied to metal roofing - point 2 below covers this topic.
2. Protective Coatings on Spray Foam Roof Assemblies (Metal and Flat Roofs) - There are many different coatings being used on flat roofs now. One category is the white or reflective coatings being sprayed on to spray foam roofing (also used on spray foam on metal roofing).
Many contractors in our marketing areas are re-covering flat roofs with spray foam (roof recovery involves going over top of an existing flat roof such as a tar and gravel roof). At issue (as it applies to this post) isn't the spray foam itself (which you also have to watch to be sure you are getting the right foam and roof assembly or application specs and the right contractor for the job scope) it is the coating used to cover the spray foam.
Many contractors come in to the roofing business specifically for the spray foam end of the business that were not roofing contractors to begin with and what can occur is error in application. Basic principles of roofing can be missed.
So when you see a quotation of 5.50 per square foot for a spray foam roof and a reflective coating be very cautious. The material cost alone in colder climates to spray a roof properly with high quality foam and to apply a covering such as described below is 5.50 per square foot by itself, forget the labour and the operating costs and the holy grail concept of retaining profit.
Specifically when coating a spray foam flat roof (that has been covered with foam on top of tar and gravel) in say Alberta, Saskatchewan or any other colder climate and you use say a 20 mil reflective coating that is typically used in Texas the reflective coating will fail - guaranteed! 40, 60, and 90 mil coatings designed for Texas will fail also.
With-out going in to great depth I will say that when we spray foam a roof we will typically use a quality provider such as BASF and we use generally accepted roofing principles (such as not covering over moisture laden roof assemblies, applying proper flashing, and the like) and the protective covering is either an EPDM roof membrane at minimum 60 mil, a liquid rubber spray on covering at minimum 60 mil, or a reflective coating that is unusually high in quality and thickness (if the client just won't have it any other way - a reflective coating that is). Another way that we have done it is coating the reflective on top of the liquid rubber which is on top of the spray foam. That way when the reflective peels, cracks, and fails the EPDM or liquid rubber is the waterproofing layer.
3. Single Ply Reflective or White Roofs - the essence of the topic covered in the article referred to above by Samir Ibrahim of Carlisle Syntec (which was the final instigating inspiration behind us finally writing an article on the topic). Single ply roofing is as far as we are concerned one of the best advances in the roofing industry for some time. However, in our experience and in our observation, some single ply roofing is not as suited for colder climates as others.
EPDM is a single ply roof and we have had great success with EPDM. EPDM comes in its typical state as a black membrane (similar to the texture of your car tire and also similar in color to your car tire). You can get it in other colors such as grey and white but we do not recommend it as it is "bleached" for lack of a better term.
I have heard many clients say that other contractors (those touting white roofing such as TPO or PVC) state that EPDM is as flimsy as a bicycle tire and that you can poke through it "just picture a bike tire" I hear clients say they've been told - poppy cock. EPDM membrane is not surrounding an inflated tire, it is adhered or fastened or ballasted to a roof assembly and the roof assembly is not full of air like a tire. A ridiculous argument. A simple search of the elasticity and strength of roofing membranes (TPO, PVC, TPO, SBS, etc) will show anyone that all the membranes are very similar in that way. All membranes (if covering an inflated tire) would burst easily if probed with a screw driver. This includes Duro-Last PVC, IKO SBS, Firestone TPO, and on and on.
Some concern we do have with white or reflective single ply roofing is covered well in the article referenced above from Carlisle and also includes the following:
a. Single Ply Failure Rates - We have noticed that white single ply roofs have a higher failure rate than the single ply EPDM in colder climates at the seams. We believe that this is not a manufacturing issue and is more likely an issue with the installer. Single ply TPO and PVC (white single ply roofing) is seamed (or the seams are connected) with a hot air welder. The hot air welder relies on the technician's ability to use it. I know myself at times when being distracted I have "missed" critical welds while on the phone or say giving orders to workers on the roof. EPDM does not use a hot air welder for seaming. EPDM uses adhesives and when applied the bond is very difficult to break and further requires less technician "attentiveness" so to speak.
b. Condensation - We have over seventy-five Fortune Five Hundred companies on our client list. We service the smallest to the largest roof assemblies. One specific system we install is PVC or TPO on specific fast food restaurant chains. We have noticed an unusual amount of condensation under white membranes on these restaurants and other installations (residential and commercial specifically in colder climates). Condensation in a roof assembly may lead to lower wind resistance, lower insulation values, reduced life-cycle, and the formation of mold.
c. Warranties - There are certain TPO and PVC roofing manufacturers advertising the best warranty on their flat roof membranes. It makes us wonder considering the issues with cracking, seams, and condensation how they are going to fare their warranty in colder climates.
d. Energy Consumption - A recent article in Alberta Construction Magazine says it well, "In Alberta, Peat says reflective roof systems might not perform as well in cold climates as they do in warm climates.
"While reflective roofs can reduce energy consumption in the summer months, they can actually increase heating costs during the winter months," he says. "A black roof, or a non-reflective roof, will transmit solar radiation into a building, which reduces energy consumption in cold temperatures. Energy calculators show that, in cold climates, reflective roofs have a heating penalty in terms of costs and energy consumption."
Energy consumption is a vital part in choosing a roof membrane and as such choice of membrane and the energy component is critical. See RCI Energy Efficiency Article on black and white roof membranes.
e. Appearance and Cleaning - A recent news cast in New Orleans states it well, "You can blame the New Orleans heat, humidity and rainy summers for what you now see on top of the Superdome.
Add a little dirt floating in the atmosphere and it gives the normally white roof, patches of grayish-brown.
"Although the roof itself appears to be a very smooth surface, it actually has little crevices and cracks in it that accumulate dirt and mold starts growing during the rainy season," said Superdome GM Alan Freeman.
Although the appearance of the roof shouldn't be a primary deciding factor, in some instances appearance can cause issue. Knowing what a roof will look like over time and the costs of maintenance should be considered.
f. Sloppy Science and Good Marketing? - The article in the Huffington Post (mentioned above) states it well... "White, or reflective, roofs have been in use for the past 15 years. Commonly referred to as "cool roofing," it has received a stamp of approval from the state of California, which has adopted its use in its building codes. It has become a LEED (Leadership in Energy and Environmental Design) standard of the U.S. Green Building Council, and has been mandated by government officials in Chicago, New York, Seattle and Philadelphia.
There is just one problem: The popularity of white reflective roofing, especially in colder climates, is based on sloppy science and good marketing."
Our Advice When Choosing a Low Slope (Flat Roof) Membrane
1. Choose a roofing contractor that installs low slope membranes every day.
2. Choose a roofing contractor that installs all or most of the different types of membranes every day.
3. Choose a roofing contractor that has an excellent workmanship guarantee - when the manufacturer is long gone and out of business or there is an urgent service requirement you will want a roofing contractor that stands behind their work.
4. Choose a roof membrane that is suitable for and has performed well for decades in your climate. In southern US states almost any membrane seems to be a good choice and in colder climates such as northern US states and colder Provinces in Canada we believe you should look toward traditional Tar and Gravel, SBS Torch On, and EPDM. In areas of Canada like downtown Toronto, southern Ontario and Vancouver perhaps even consider a white roof such as TPO or PVC.
5. Take a close look at the pro's and con's of each flat roof membrane, look at reviews, and ask contractors about the different systems, different ways to install the systems (fully adhered, ballasted, mechanically fastened, etc), and specifically what each contractor is offering in their roof assembly specifications (what the roof system is actually made up of as this can vary significantly when quoting is in process). See article on various flat roof systems available.
Tyler Sinclair - Staff writer at General Roofing Systems International
Article Topics: Building energy efficiency, EPDM roof, flat roof, flat roof material, green roofing, PVC roof, reflective roof, roof membrane, single ply roof, SPF roofing, spray foam roof, TPO roof, white roof membranes, spray foam roof coatings, white roofs, Vancouver, BC, Alberta, Calgary, Red Deer, Edmonton, Fort McMurray, Saskatoon, Regina, Saskatchewan, Manitoba.
About General Roofing Systems Canada (GRS)
General Roofing Systems Canada (GRS) is a diverse privately held building envelope, exterior renovation, and roofing contractor serving local and national accounts in various areas of Canada. GRS started serving Western Canada in 2007 as exterior renovation sub-contractors and has since grown year over year. GRS also has a growing online presence in the United States, UK, and around the world (General Roofing Systems Intl).
The General Roofing Systems Canada (GRS) project portfolio extends from Vancouver BC to Whistler, Kelowna, Cranbrook, Fernie, to Southern Alberta - Lethbridge, Calgary, Red Deer, up to Edmonton, Grand Prairie, Fort McMurray, AB, N.W.T., over to Lloydminster, and in to Saskatchewan to Yorkton, Saskatoon, Regina, to Winnipeg Manitoba and points between. GRS is also known to send specialized crews to Ontario and Eastern points of Canada. GRS services national Canadian roofing accounts with counter-parts in Ontario and Eastern Canada and their experts have been tasked internationally.
General Roofing Systems Canada (GRS) projects range in size from a storage shed in a residential back-yard to the largest commercial and industrial facilities in the world.
Some project locations and/or organizations that trust GRS to protect their assets...
Alberta Federation of Labour, Azko Nobel, Sobeys, City of Edmonton, McDonalds, ENBRIDGE, United Cargo Logistics, Canadian Freightways, Waste Management, Four Points Sheraton Hotels, Schlumberger, WILLBROS, TransForce, RONA, Toran Power, FORTIS Alberta, Shell Canada, Enmax, Credit Union, Interprovincial Pipeline, Toronto Dominion Bank, TD Waterhouse, TELUS, Dominion of Canada, Chinook Shopping Centre, Kal Tire, IKEA, McCains Foods, Chapters Book Stores, Starbucks, Visions Electronics, Pizza Hut, Shoppers Drug Mart, Greyhound, All Weather Windows, Husky Energy, EPCOR, Canadian Tire, Tim Horton's, Pick N Pull International, ServiceMASTER Restoration, Alberta Energy Center, On-Side Restoration, Imperial Oil, National Oil Well Varco (NOV), Weatherford, ALTALINK, Kiewit Energy, Cineplex Odeon, YMCA, Fountain Tire, Teck, Kiewit Infrastructure, Best Western, and more.
Contact General Roofing Systems Canada (GRS):
Toll Free +1.877.497.3528 | Email info@grscanadainc.com | Website: www.grscanadainc.com
