# bidding against Durolast roof. Differences in PVC, what makes one better than the ot



## Grumpy (Oct 29, 2008)

I'm bidding against a durolast contractor on a roof.  Durolast contractor said tear off the roof and install new.  May be a little premature, but the point of contact was in agreement so  who am I to argue. But I told him we don't install durolast.  <br><br>I explained I like PVC, not all PVC's are the same.  I also said "It's not very professional to slam anyone. But I can tell you're an educated kind of consumer, so do some research on the internet as to the reputation of the materials you're considering having installed. I think it'll be an eye opener."  <br><br>But it would have been nice to have been able to talk scientific without getting into brand names.  I commonly install Versico PVC, which is made by Flex. Sometimes JM, though not often.   So the parts of the membrane include the pvc base, the scrim, the top weather layer.  Some PVC membranes are prone to cracking, but I'd like to be able to explain why. Explain why one weathers better than the other etc...   <br><br>Doing some web searches I am not really finding the data I want to be able to backup the comment "My PVC is better than his PVC"<br><br>Any input?<br>


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## Grumpy (Oct 29, 2008)

Stupid forum since the update. Every time I try to make a new forum post, I get the error message that I don't have permission to add new tags. I erase the tags because of this but the forum tries to auto add the tags. Then it adds all the bull kaka html code script.


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## Pie in the Sky (Dec 21, 2011)

http://www.roofingcenter.org/syncsh...b Testing of Poly Vinyl Chloride Roofs(1).pdf

Check out heading 7 - Plasticizer content. I know Stan, Hes a smart guy who works for a great Manufacturer (sarnafil). Anyway Ive had it explained like this: Plasticizers are many different types with different molecular weights. Higher the molecular weight the more expensive the plasticizer. The higher the molecular weight, the larger the molecule, the slower it migrates out of the sheet. (very simplified) Cheap PVCs use cheap plasticizers. thats why some of these roofs cant handle hail after 5-8 years they have all migrated out. This is also one of the reasons early PVC's failed and because of no reinforcement. 
TPO came out and was all the rage because it has no plasticizers to leach out. Thats why you can stant a 60 mil 10foot sheet on end in the winter. This is why youll see lichen growth on some PVCs but rarely on a TPO, the plasticizers are food.


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