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Discussion Starter · #1 ·
Our roofer offers Rhino Wrap Synthetic Underlayment as a standard. If we want "Certainteed Diamond" underlayment (we'll have Certainteed Landmark Pro shingles), it is considered upgrade. Is it worth the extra cost to upgrade to "Certainteed Diamond" underlayment? Need a decide asap. Appreciate a quick reply. Thank you!
 

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#1 Go back and add your location to your profile.
Not worth the extra money, underlaymant is not what keeps a roof from leaking.
Only time it would do anything is if the shingle blew off.
 
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Discussion Starter · #7 ·
Thank you!

also the contract has

1) for shingles, it will be installed with four 1 1/4" galvanized roofing nails.
2) for flashing, copper flashing will be installed at chimney. Aluminum flashing will be installed at all other abutting areas.

Is this detailed enough? Thank you!
 

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kt82 said:
re; I use Rhino synthetic no matter the shingle being installed.
Are synthetic "felts" walkable at 6/12 pitch? how does a morning dew
affect walk ability?
Yes. I can personally walk on synthetic underlayments up to a 9/12.

I'm not sure about morning few because we roof what we tear off the same day except for extreme cases.
 

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I wouldn't worry too much about the brand of synthetic underlayment.

When I did my roof this summer I tried to research synthetic underlayments, and I couldn't find anything that says there is any significant advantage to synthetics versus felt, or any particular brand of synthetic versus another once the roof is complete. There are advantages for the installation itself, but once the roof is done, it's the quality of the shingles and installation that will make the difference on your roof.

Unfortunately with these types of new building materials, it takes several decades before you know how well they worked. So come back and ask somewhere around 2030 or 2040 and you will get more informed answers.
 

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Polyethylene is not a "new" building material. In this application, it less than 30 years old, but hardly unknown commodity.

It is vapor impermeable, more so than felt, which is a benefit. Enough to make me choose a roofer over another that uses felt...no.
 

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I wouldn't worry too much about the brand of synthetic underlayment.

15# felt in the Texas market is not even 15 lbs anymore.
it is more like kraft paper with no oil in it
it rips,crinkles in the morning when cold, and trying to walk on it
when the temp hits 100 is futile
why when I was younger and Certainteed used virgin paper
and real tar ,never mind
.it's 19 F out there and I refuse to leave the house
 

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Polyethylene is not a "new" building material. In this application, it less than 30 years old, but hardly unknown commodity.

It is vapor impermeable, more so than felt, which is a benefit. Enough to make me choose a roofer over another that uses felt...no.
I thought the shingle manufactures required the underlayment to be "vapor permeable" or the warranty was voided?
 

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I was wondering where the water vapor between the underlayment and the OSB goes
#15 has a metric perm rating of 37.7
#30 22.2
while a typical "peel and seal" membrane is rated at .05
which implies to me that no vapor will pass thru the membrane which is good right?
I guess I should get back and finish my taxes.
 
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