# PVC vs. EPDM vs. Bitumen



## Ed the Roofer (Jan 27, 2007)

You opened up a big bag of generalizations without knowing it, py generically just referring to "PVC" membranes.

Is any white membrane a PVC membrane?

Do most white membranes contain a portion of PVC in it's formulation?

The answers are that each and every unique manufacturer formulate their own recipe for their white thermoplastic membrane roof products.

Some, such as TPO membranes, while offering a lower initial price, have been shown to fail rather regularly, in about 10-12 years time, regardless of the quality of the installation.

Others, such as pre-fabricated systems, like Duro-Last, can perform quite well, but is totally dependant on the quality conscientiousness of the installation crew for final aesthetic appearances, due to the factory folded creases which must be streched out properly when laying it out.

Others, while not being factory fabricated and coming only in roll goods, now depend on the quality of the installer doing the seam welding or the knowledge of the operator running the automatic robotic welder running the saeams.

Once you have a quality contractor familiar with any of those systems and see their actual work, then you will know if that roof membrane will be a good fit for you.

What aspects of the roofing material are the most important to you?

Ed


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## almt (Mar 13, 2009)

Thanks for responding. I've been reading various articles in the forum, especially from you. They have been quite informative as I had to brush up on all the terminologies.

I have two quotes so far. One is for a Fibertite laminated to insulation. The other is torch down modified bitumen. The bitumen quote is quite a bit more expensive, although that includes replacing vents/pipes/baseboards. Neither recommends EPDM. 

I'm looking for something that is durable, say 15-20 years? I don't expect anybody to walk on it, other than perhaps birds that might take their food on the roof and possibly poke into the roof. 

In any case, as you noted in other forums, it's the quality of the installation that matters. Still, I don't want to deal with any maintenance/repairs and unclear which one is more maintenance free.


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## jaros bros. (Jan 16, 2009)

I like using the EPDM. It comes in different thicknesses, the thicker the longer it lasts in general. Most of the degradation is caused by ultraviolet rays. I agree with the previous post that you need to see some of the work and go with a contractor that is proven. They also make EPDM in a white color. I think that if you buy a good quality EPDM you can get 15-20 years out of it. Usually you can get it as one seamless piece if your roof isn't too big.


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## tinner666 (Mar 14, 2005)

.060 or .090 Fiber Re-inforced EPDM is hardy.


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## Ed the Roofer (Jan 27, 2007)

It is just so extremely rare that I have been on a decent sized epdm rubber roof, that I did not detect some problems with the seams, even if an active leak did not yet result.

Too many variables influence the integrity of the seam strength. Particulary, the installers conscientiousness, plus the dust and talc that is always there, which needs to be properly wiped off with a continuing supply of clean rags and seam wash solvents.

A pvc seam, on the other hand is much easier to weld together, which increases the strength of the sheet.

Fibertite is a good product, but once again, I reitterate that the contractors previous jobs must be checked out.

The reflective qualities would suit you well in the Sunshine State too.

If per chance you do wind up going with epdm, I recommend a fully adhered system typically, but your case may be different. Then, you either have the additioanl cost of purchasing the white version of that membrane, or paying a regular maintenace fee of recoating it white every 5 or so years.

Ed


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## johnk (May 1, 2007)

A well installed modified roof would last you 15 yrs no problem as long as you don't have any ponding issues.(IMO of course)


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## Ed the Roofer (Jan 27, 2007)

That is the key though John.

How many guys do not heat up the entire roll?

I see more shoddy wormanship on most modified bitumen systems than any other, because it is too easy for a guy to pick up a torch and think he is doing it right.

How many contractors have employees that are CERTA Aprroved?

Not many.

Pick a system that is less dependant on the workers skill and integrity, or pick the Right Company in the first place to do the job and you will be better served.

Ed


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## johnk (May 1, 2007)

Ed the Roofer said:


> That is the key though John.
> 
> How many guys do not heat up the entire roll?
> 
> ...


Your right Ed,theres only a select few in my area I would actually recommend(including myself).But you know yourself its one hell of a roof.I have roofs I've torched 15 yrs ago that have no signs of failure.Yes like Ed said though....everyones a torcher:yes:


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## jaros bros. (Jan 16, 2009)

I think you've both mentioned the key to getting a good roof with these materials. Installation is everything. Everyone thinks it looks easy but there are a lot of details and a lot of fussiness, especially when it comes to seams, termination details, and attachment.


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