Weatherguard v.s. Ice & Water Shield, Priming first?
I want to make sure my new roof is installed correctly. Some companies use Grace's peal and stick, and other's use Certainteeds.
My concern is that I have OSB sheething. I know the Grace product requires priming, which the contractors say is not needed. I do not believe Weatherguard requires priming on OSB (or does not require the use of their primer).
Is priming needed with each product?
What are the other pros/cons of each? I am in San Jose, CA and not concerned with Snow/Ice, just water particularly around flashings & dormer.
I copy & pasted directly from the Grace website at: Grace
Notice the words I marked in Red.
Prime concrete, masonry surfaces and Dens-
Glass Gold® with Perm-A-Barrier®WB
Primer. Prime wood composition and gypsum
sheathing with Perm-A-Barrier WB Primer
if adhesion is found to be marginal (refer to
Technical Letter 12, Use on Oriented Strand
Board (OSB) Roof Sheathing). Apply
Perm-A-Barrier WB Primer at a rate of
250–350 ft2/gal (6–8 m2/L). Priming is not
required for other suitable surfaces, such as
plywood and some gypsum sheathing,
provided they are clean and dry.
From letter 12
In applications where membrane adhesion to
the OSB is found to be marginal, or windy
conditions are likely prior to covering with
the exposed roofing materials, nail off the
perimeter of the membrane with roofing or
cap nails at intervals of 12 inches (300 mm)
on center. If moderate or high wind conditions
are likely, additional nailing in the field
of the sheet may be necessary. Staples should
not be used in place of nails. As an alternative
to using nails, apply Perm-A-Barrier®WB
Primer to the roof deck at a coverage rate of
250–350 ft2/gal (6–8 m2/L). Perm-A-Barrier
WB Primer and the surface of Grace
underlayments are slippery when wet.
Allow the Perm-A-BarrierWB Primer to
BTW, Certainteeds ice guard is as good a product on sloped roofs as Grace is.
Thanks. I do not quite understand the reasoning behind nailing it or priming it. Is it to keep out water or just keep it down in place until underlayment and shingles are applied over it?
For example, if I have good enough adhesion to keep it in place before putting down the underlayment and shingles, do I need to prime or nail it?
I have installed lots of this product for roofing. It sticks directly to the OSB and it is very very adhesive. Especially in the warmer weather. When it is cold it can be a little less adhesive. Either way we have never done any extra to install it but remove the backing and lay it down. Once it is down it isnt going anywhere and once the shingles are on top you can expect a pretty solid product.
As soon as it is warm, it will be well adhered.
Thank you for the reply. My new roof was put on this week and I selected to use Winterguard since we were using other Certainteed products, and I felt more comfortable that the directions didn't recommend a primer being used. The weather was fairly cool and it was not adhearing very well, but it seems like a moot point because it stayed down well enough for two layers of 30# to adhere to it, and after shingling/nailing, it was set well for warmer weather. If the roof was installed correctly, it shouldn't need it set anyways :-p
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