# TPO Newbie



## TTony (Dec 13, 2011)

Does anybody have a opinion of whether cut edge membrane needs to be used on cut tpo hanging down (2-3 inches, to be covered with metal) over the roof edge?


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## 1985gt (Dec 21, 2010)

Yes as with epdm we all ways leave enough material to cover the wood nailers and then some. I think they all should be done this way although if you use the TPO metal you don't have to do it, I still would.


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## linderman (Mar 29, 2012)

1985gt said:


> Yes as with epdm we all ways leave enough material to cover the wood nailers and then some. I think they all should be done this way although if you use the TPO metal you don't have to do it, I still would.


 

I agree with 1985GT; ALL single ply systems should extend over the wood blocking at the edge as much as your fascia metal will allow


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

I think he means cut edge sealant? If he does its a pretty good question. Ive never thought of it. I probably would say its not required cause it shouldnt get wet and if it did, it would affect much.


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## linderman (Mar 29, 2012)

sorry about that, I did misunderstand you

you DONT need to put cut edge sealant on that area as its technically not exposed to the weather


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## TTony (Dec 13, 2011)

Thats exactly right I meant cut edge sealant. Thanks for the comments. I'm sure I have more questiopns to come.


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## 1985gt (Dec 21, 2010)

Sorry I read it wrong too!  I would say No but if you think about it if wind driven rain does blow rain up under the drip edge it could actually wick into the membrane. Highly unlikely so I will still go with no and keep installing it the same way. :thumbup:


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## RoofYourWorld (Jul 27, 2011)

linderman said:


> sorry about that, I did misunderstand you
> 
> you DONT need to put cut edge sealant on that area as its technically not exposed to the weather


You don't need to put cut edge sealant on a part of the membrane that will not be exposed to the elements.

It's used to in the field and around penetrations where there is a potential for water to absorb in the scrim (which is exposed by cutting the membrane).

Most cut edge sealant is applied at membrane overlaps...so you'd have quite the time installing it as it is wrapped over the edge of a roof!


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## LCG (May 30, 2011)

Just another reason why TPO sucks!


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## Grumpy (Oct 29, 2008)

LCG why? Cut edge sealant is the reason TPO sucks? Hmmmm... Interesting.


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## RoofYourWorld (Jul 27, 2011)

Grumpy said:


> LCG why? Cut edge sealant is the reason TPO sucks? Hmmmm... Interesting.


I was thinking the same thing... never realized it was such a difficult part of the installation process. Gotta drop that mentality or you're going to get left behind!


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## LCG (May 30, 2011)

Grumpy said:


> LCG why? Cut edge sealant is the reason TPO sucks? Hmmmm... Interesting.


Not the only reason. There are many!

I'll send you the last TPO study I read soon.


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## Grumpy (Oct 29, 2008)

So what's your membrane of choice?


Lots of studies saying tpo is worthless. None of the tpo jobs I have installed have failed yet. Fingers crossed because according to the hot and pvc guys, TPO is going to put me out of business.

If you want a 10 or 15 year roof, I don't have a problem with TPO. If you want a 20 or 30 year roof, TPO is not the way to go. PVC would then be the membrane of choice.


Back to cut edge sealant. PVC has it too


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## LCG (May 30, 2011)

RoofYourWorld said:


> I was thinking the same thing... never realized it was such a difficult part of the installation process. Gotta drop that mentality or you're going to get left behind!


 :laughing:


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## urethaneroofer (Jul 2, 2009)

you don't need cut off sealer if it's covered with metal. Only exposed cut off edges need to have the sealer.


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