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Old 09-14-2011, 01:41 PM   #1
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PVC Roofing Shingles


I have a 3tab shingle roof and I live in a hot desert community. I have been doing a lot of research on cool roofing materials and keep coming back to the impressive thermal numbers for white PVC roofing membrane panels.

My question is twofold:

1. Everything I have found says this stuff is only used on flat roofs but it seems a shame it can't somehow be used on homes. Does anyone know of any kind of white PVC material ever being used on a sloped roof (3:12)?

2. I have been imagining a new product: standard 12x36 3tab shingles made out of a white PVC membrane type of material instead of asphalt & fiberglass. I am sure it would need to be thick (>90 mil) and have extra strong fiber/scrim reinforcing in the nailing zone.

I have no idea about the fire rating of this material used in such a configuration even though I understand PVC is naturally fire resistant due to its chlorine content.

I suspect this would be a very lightweight shingle, similar to metal shingles, and if so would be well suited to using as a "2nd layer" reroof over typical asphalt shingles, which would be a fast way to make a house more energy efficient. Also like metal shingles it would need to be textured a little to make walking on sloped roofs more feasible.

So anybody here know if this has been explored by any manufacturers or inventors ? If so what happened ?

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Old 09-15-2011, 08:29 AM   #2
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While I appreciate your thoughtfulness and logic on this, I don't think they will explore this avenue much, if at all, because it is filled by other products.

Most people are just looking for energy star certification and that can be achieved via conventional shingles and other roofing systems as it.

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Old 09-15-2011, 01:45 PM   #3
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Wash, thanks for the reply but with all due respect that is a very narrow and IMHO very erroneous view. Most people are not "... just looking for Energy Star certification ..." -- the bottom line is that most people who choose to Go Green or Go Cool are doing it because they are looking for real savings on their energy costs.

Energy Star certs are desirable because they allow people to save more money thru tax rebates which lower their costs of installation. But since the rebates are only a partial offset of the costs the ultimate motivation is all about the long term energy cost savings.

Can anyone seriously think that given a choice between Energy Star asphalt shingles (with a heat reflective factor of about 26%) or using White PVC shingles (with a heat reflective factor of about 91%) that any consumer would opt for the one that is 65% LESS EFFECTIVE if the materials cost was comparable?

Beyond the money (but not necessarily excluding it) there are also a lot of folks out there who are choosing the Green/Cool path because they are environmentally conscious activists (sometimes known affectionately as "tree huggers") or they are looking for ways to "reduce dependence of foreign oil". Neither of these motivations has anything to do with Energy Star certification.

Compared to asphalt material the advantages of PVC are:
  • it is not made from petroleum,
  • it is recycle-able,
  • it is lighter weight (thus having less transport costs) and
  • it is probably more durable.
If they were priced low enough and designed to be installed just like other asphalt shingles are, PVC shingles could prove to be a huge boon to the roofing workers economy and could create a lot of jobs even.
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Old 09-15-2011, 03:27 PM   #4
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Except they would look like sh!t on a white chicken.
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Old 09-15-2011, 09:18 PM   #5
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Hmmm .. and white painted roof look so nice? or galvanized tin roofs? or solar-electric panels?

The oldest rule in architecture is that form FOLLOWS function.

First it has to work, then you can worry about how it looks.
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Old 09-15-2011, 09:47 PM   #6
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2 manufacturers I am aware of have have "Imprinted" shingle like imaged PVC membrane roofing systems on the market.

They are;

1. IB Roofing

http://www.ibroof.com/home_owners.html

and

2. Duro-Last Roofing

http://www.duro-last.com/shingleply/ Corrected Link



If I have time, I will get a link for you later on. (Done)



Ed



.

Last edited by Ed the Roofer; 09-17-2011 at 01:13 AM. Reason: Corrected Link
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Old 09-16-2011, 08:47 AM   #7
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Quote:
Originally Posted by JR28 View Post
Wash, thanks for the reply but with all due respect that is a very narrow and IMHO very erroneous view. Most people are not "... just looking for Energy Star certification ..." -- the bottom line is that most people who choose to Go Green or Go Cool are doing it because they are looking for real savings on their energy costs.

Energy Star certs are desirable because they allow people to save more money thru tax rebates which lower their costs of installation. But since the rebates are only a partial offset of the costs the ultimate motivation is all about the long term energy cost savings.

Can anyone seriously think that given a choice between Energy Star asphalt shingles (with a heat reflective factor of about 26%) or using White PVC shingles (with a heat reflective factor of about 91%) that any consumer would opt for the one that is 65% LESS EFFECTIVE if the materials cost was comparable?

Beyond the money (but not necessarily excluding it) there are also a lot of folks out there who are choosing the Green/Cool path because they are environmentally conscious activists (sometimes known affectionately as "tree huggers") or they are looking for ways to "reduce dependence of foreign oil". Neither of these motivations has anything to do with Energy Star certification.

Compared to asphalt material the advantages of PVC are:
  • it is not made from petroleum,
  • it is recycle-able,
  • it is lighter weight (thus having less transport costs) and
  • it is probably more durable.
If they were priced low enough and designed to be installed just like other asphalt shingles are, PVC shingles could prove to be a huge boon to the roofing workers economy and could create a lot of jobs even.
Couple of points worth nothing when it comes to this material choice and its pros/cons.

High reflectivity/emissivity roofing is great but depending on the construction type will have little to no impact in a customers overall heating/cooling costs. With a conventional attic style vs. insulated roof deck, the savings are nil when you have a proper insulation layer in the attic.

Combine that with the fact that a white roof only fits a very select customer aethetic profile and you have reduced its application even further.

In an insulated roof deck scenario, it does have some benefits, however, you can easily create a similar efficiency in a metal roof.

Metal roofs vs. PVC
  • More proven historical track record for durability
  • Also green in that they are sustainable
  • Also contain recycled content
  • Do no require special UV stabilization agents to protect the substrate against UV degradation (i.e. Titanium dioxides for PVC)
  • Non combustible and no off gassing if melted
  • Established and accounted for thermal expansion rates
  • Painted finishes in off-white color spectrum with much better than energy star ratings. True, white will be best, however you are somewhat pigeon holing your self.
  • Light weight
Metal roofs can also be installed in over deck venting applications which will create a more efficient roof system even when compared to a white roof with higher emissivity/reflectivity ratings.

If installed on insulated roof deck applications, I would be wary of the permeability rating of PVC and its ability to allow moisture from inside the home to diffuse and dry to outside.

PVC also has and very high coefficient of expansion. In the window world we can accommodate for this with floating type glazing bead and other movement independent connections, however, it is still something that needs to be engineered into the system.

Have you ever seen some of the poorly engineered synthetic slates. They curl at the edges and look like garbage after about 2 weeks in some cases. Unless you are running a very gauge PVC, I would be concerned about curling edges as well. Metal is much more rigid and resistant to wind lift.

A metal roof can also be re-finished to change the look or renew the paint. PVC can only be painted in very controlled situations.

I am all about high efficiency roofing systems but you can just as easily add proper insulation to insulation layer and get the color/style you want vs. a white shingle.
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Old 09-16-2011, 09:42 AM   #8
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Windows on Wash has hit it spot on. Sorry to say that your shingle idea will never come to fruition for many reasons (most already listed here), mostly because the material is just not suitable. White roofs also tend to get dirty and lose a good poriton of reflectivity (cleaning does not help much).

I think you're a little too caught up in this 'green' hype. There is no wonder material that can magically lower costs. Proper design, careful construction, and good material selection. It's not sexy like the 'green' hype, but that's how it is.
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Old 09-16-2011, 06:59 PM   #9
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Quote:
Originally Posted by Windows on Wash View Post
Couple of points worth nothing when it comes to this material choice and its pros/cons.

High reflectivity/emissivity roofing is great but depending on the construction type will have little to no impact in a customers overall heating/cooling costs. With a conventional attic style vs. insulated roof deck, the savings are nil when you have a proper insulation layer in the attic.
True, but in the real world a lot of folks own homes that have less than stellar insulation due to poorly designed and built houses. My idea is targeted at those who would have to spend fortunes to get good R ratings and simply don't have the resources at this time. Maybe if they could get 10 years of energy savings they could save enough money to afford a good insulation/energy leak retrofit.

Quote:
Combine that with the fact that a white roof only fits a very select customer aesthetic profile and you have reduced its application even further.
Maybe you haven't noticed but we are in hard economic times and many people are doing anything to save a buck, including slopping white paint over asphalt shingles (which does look like crap). The market is there for a low cost entry level product to save energy. Especially if the numbers are right and the technology is a "cutting edge" new concept.

Quote:
In an insulated roof deck scenario, it does have some benefits, however, you can easily create a similar efficiency in a metal roof.

Metal roofs vs. PVC
  • More proven historical track record for durability
  • Also green in that they are sustainable
  • Also contain recycled content
  • Do not require special UV stabilization agents to protect the substrate against UV degradation (i.e. Titanium dioxides for PVC)
  • Non combustible and no off gassing if melted
  • Established and accounted for thermal expansion rates
  • Painted finishes in off-white color spectrum with much better than energy star ratings. True, white will be best, however you are somewhat pigeon holing your self.
  • Light weight
Metal roofs can also be installed in over deck venting applications which will create a more efficient roof system even when compared to a white roof with higher emissivity/reflectivity ratings.
I wholeheartedly agree that metal is a superior product for all the reasons you list, but this is like comparing Hummer trucks to VW bugs. Just plain different markets.

Metal shingle roofs are certainly an excellent choice over standard asphalt shingles, but (in my area) costs are $450 to $550 per square (for materials alone - before installation) so the metal products have an extremely high financial barrier to entry for the market.

Of course there is no truth to the rumor that since these roofs lasts twice as long the manufacturers price it twice as much. :P

Note however that in the metal roofing industry you can see that some big players are moving towards products with methods of installation that mimic those for asphalt shingles. Why? Well I am thinking that they realize they can sell more product if they could make something that did not require roofing companies (which are also front line sales reps) to buy special equipment and invest in special training.

Low costs and ease of application are the 2 key factors to capturing current market share which is probably the reason why 3tabs and their new cousins dimensional shingles are so dominant.

Quote:
If installed on insulated roof deck applications, I would be wary of the permeability rating of PVC and its ability to allow moisture from inside the home to diffuse and dry to outside.

PVC also has a very high coefficient of expansion. In the window world we can accommodate for this with floating type glazing bead and other movement independent connections, however, it is still something that needs to be engineered into the system.

Have you ever seen some of the poorly engineered synthetic slates. They curl at the edges and look like garbage after about 2 weeks in some cases. Unless you are running a very gauge PVC, I would be concerned about curling edges as well. Metal is much more rigid and resistant to wind lift.
There certainly are a lot of engineering issues about PVC that need to be answered before this idea can be viable, which is why I was asking if anyone had done any practical work (or even basic research) with the material for use as an asphalt shingle equivalent application. Just because these questions have not been answered yet does not mean the answers will be no good.

As for poorly engineered slates, remember that the first fiberglass shingles had the same kinds of problems early on. Today those problems with fiberglass are rare. Any good idea can be screwed up by poor engineering. Don't blame the material if the design and testing is what is at fault.

Quote:
A metal roof can also be re-finished to change the look or renew the paint. PVC can only be painted in very controlled situations.
Absolutely true, but metal roofs are supposed to last for ~50 years. In no way would a PVC shingle or any other common shingle roof last that long ... and yes you can paint some asphalt roofs but the preferred way to change the look of a shingle roof has always been to re-roof when the time is right.

Quote:
I am all about high efficiency roofing systems but you can just as easily add proper insulation to the insulation layer and get the color/style you want vs. a white shingle.
Of course you could also do both!
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Old 09-16-2011, 06:59 PM   #10
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Thanks Ed. Unfortunately this type of roofing is not what I am talking about at all.

The link for Duro-Last is wrong (should be http://www.duro-last.com/shingleply/) but since they are one of the major players in white pvc roofing for flat roofs (mostly for commercial structures) so I am already familiar with their product line.

Both the Duro-Last and the IB products [A] do not install like standard shingles (they require seam welding equipment), [b] are intended for flat or very low-slope roofs, and [C] are not a pure white (high reflectivity) surface.

In short these are standard PVC flat roofing membranes that have been cosmetically disguised to LOOK like a standard asphalt shingle roof, which is the exact opposite of what I am asking for.

I genuinely appreciate the effort though.
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Old 09-17-2011, 10:30 AM   #11
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Quote:
Originally Posted by JR28 View Post
True, but in the real world a lot of folks own homes that have less than stellar insulation due to poorly designed and built houses. My idea is targeted at those who would have to spend fortunes to get good R ratings and simply don't have the resources at this time. Maybe if they could get 10 years of energy savings they could save enough money to afford a good insulation/energy leak retrofit.
Hence the reason that I said "In an insulated roof deck scenario, it does have some benefits, however, you can easily create a similar efficiency in a metal roof" two sentences later.

Poor insulation work poorly in both seasons and should be addressed first prior to investing into a roofing system that will only work in one season (and work negatively in the other season for that matter).

I have rarely been into a home that would cost fortunes to repair the insulation/envelope systems. Those should be fixed first prior to reverse engineering a repair in a roofing system.

Quote:
Originally Posted by JR28 View Post
Maybe you haven't noticed but we are in hard economic times and many people are doing anything to save a buck, including slopping white paint over asphalt shingles (which does look like crap). The market is there for a low cost entry level product to save energy. Especially if the numbers are right and the technology is a "cutting edge" new concept.
I don't think sarcasm is necessitated in this application. Many people are struggling and using it as the launching point for a jab does not honor their suffering.

If my options are PVC shingles or white paint, I will obviously opt for the high reflectivity in the PVC. I also know that an overwhelmingly majority of the homes can be retrofitted to provide far more comfort improvement and utility reduction before putting on an PVC shingle (to replace an existing shingle that is okay)

Quote:
Originally Posted by JR28 View Post
I wholeheartedly agree that metal is a superior product for all the reasons you list, but this is like comparing Hummer trucks to VW bugs. Just plain different markets.

Metal shingle roofs are certainly an excellent choice over standard asphalt shingles, but (in my area) costs are $450 to $550 per square (for materials alone - before installation) so the metal products have an extremely high financial barrier to entry for the market.

Of course there is no truth to the rumor that since these roofs lasts twice as long the manufacturers price it twice as much. :P

Note however that in the metal roofing industry you can see that some big players are moving towards products with methods of installation that mimic those for asphalt shingles. Why? Well I am thinking that they realize they can sell more product if they could make something that did not require roofing companies (which are also front line sales reps) to buy special equipment and invest in special training.

Low costs and ease of application are the 2 key factors to capturing current market share which is probably the reason why 3tabs and their new cousins dimensional shingles are so dominant.
Everything is a trade off. I can tell you that your materials estimate for standing seam and installation consumables is about 2X higher than it actually is. That being said, the overall profile is much more expensive to install because of the material handling procedures and skill set required to do it properly.

You can buy the panels already run and the only specialty tools are metal snips, seamer, and other misc. metal working tools. Nothing egregiously expensive.

As far as the interlocking panel systems, there are few specialty tool required if any (depending on how you define them) to do that roof. Again, it requires more skill and careful installation as compared to your standard asphalt roof.

I disagree that they are different markets (metal and asphalt). They are going to be more expensive but what will the cost of asphalt be in 20 years? The cost of that steel roof is easily going to be cheaper or the 50 year lifespan when compared to asphalt.

Quote:
Originally Posted by JR28 View Post
There certainly are a lot of engineering issues about PVC that need to be answered before this idea can be viable, which is why I was asking if anyone had done any practical work (or even basic research) with the material for use as an asphalt shingle equivalent application. Just because these questions have not been answered yet does not mean the answers will be no good.

As for poorly engineered slates, remember that the first fiberglass shingles had the same kinds of problems early on. Today those problems with fiberglass are rare. Any good idea can be screwed up by poor engineering. Don't blame the material if the design and testing is what is at fault.
I think the research as to whether or not PVC would be a viable roof material is well demonstrated in other building materials (i.e. window and siding). Siding would likely be the gauge you would be considering and despite material manufacturer claims, I have not seen 20 year old vinyl siding that looks good or has stayed true to its original installed form. These are interlocking panels at that. If you were looking at a roofing system (cost effective) you would be looking at a overlapping system that seals to the course below via bitumen, etc. Most of the shingles resistance to blow off (after the bitumen breaks down) is as a result of shingle weight. Hence the reason that companies sell 50-year shingles that are based on the same technology as the 30-year shingles which everyone would agree is laughable.

I am not saying the material could not be designed to work, I just think that the current high reflectivity asphalt shingles fill that gap between metal and traditional asphalt shingles.

Quote:
Originally Posted by JR28 View Post
Absolutely true, but metal roofs are supposed to last for ~50 years. In no way would a PVC shingle or any other common shingle roof last that long ... and yes you can paint some asphalt roofs but the preferred way to change the look of a shingle roof has always been to re-roof when the time is right.

Of course you could also do both!
I am not try rain on your parade but you posted up the thread with the intention of getting feedback on your question.

Running a simulation for Phoenix, AZ and comparing a high reflective asphalt shingle (30) vs. a high reflectivity PVC shingle (theoretic 90 and estimated at higher than TPO numbers) on a home as specified:
  • 2000 ft2
  • R-11 attic insulation
  • Mid efficiency heat pump
  • 2-8:12 pitch
  • 1 floor
Netted a whopping $32 of savings per year. Both reflectivity numbers are based on the highest initial ratings for comparative purposes.

If you have more than an totally inadequate R-11, the number shrinks even further.

I am not sure there is going to be a large cry in the market for a material that will net someone only about $40 of savings per year when proven materials are available.

I am not the authority on this though and I would encourage you to follow your drive on this if you think it is truly a viable option.
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Old 09-17-2011, 01:30 PM   #12
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W.o.W. :
A very well written response and very useful information. Thank you for the "Phoenix" numbers you crunched as that does put a new perspective on it.

While I still think this might be an interesting idea to explore for other reasons if the energy savings are so low then perhaps you are right and the market is too small.

I still would like to see something that doesn't have to be made from petroleum replace the common asphalt shingle just as fiberglass has mostly replaced the organic mat shingles. It doesn't have to be a PVC/scrim membrane but something similar (there are soooo many synthetic compounds) is probably worth considering. Think of it as a quest for an improvement in an old technology.

PS: Those metal roofing costs I mentioned were for metal shingle (stone coated steel and similar) systems, not standing seam systems. From the beginning my quest has been for a system that has an installation method highly comparable to asphalt shingles. New metal shingle systems are getting very close.

Thanks again.
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Old 09-17-2011, 04:54 PM   #13
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The metal panels (stone coated steel) do not require as much a specialty tool as they do a specialty contractor. That is where you are paying the premium as compared to the average shingle installed prices.

That being said, I think it bares consideration that you should compare a good shingle installer to a good metal installer. Both will take the care required to properly install both materials vs. the cheap shingle hanger vs. the more expensive metal installer.

I agree with you that I would like to see some more options, but I think the large roofing manufacturers know the data and the data shows that the high reflectivity coatings don't yield much ROI. Asphalt is a pretty terrible roof material in my opinion but it is like the vinyl window of the window world (good performance, cheaper to manufacture, and pretty darn good performance).

I always appreciate a good debate and your heart is in the right place.

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