Which type of roof underlayment is recommended these days? Fiberglass “felt paper” or a breathable membrane?
Thanks.
Which type of roof underlayment is recommended these days? Fiberglass “felt paper” or a breathable membrane?
Thanks.
In issue #314, Fine Homebuilding published an article titled “The End of Deep Energy Retrofits” by Rachel White of Byggmeister. The premise was that deep energy retrofits are not as…
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Get home building tips, offers, and expert advice in your inbox
Fine Homebuilding
Get home building tips, offers, and expert advice in your inbox
© 2024 Active Interest Media. All rights reserved.
Get home building tips, offers, and expert advice in your inbox
Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.
Start Your Free TrialStart your subscription today and save up to 81%
SubscribeGet complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.
Already a member? Log in
Replies
For the flat part of the roof, I'd bituthane the whole thing. Take your pick on the other areas.
Neither.
Look at Titanium UDF or RoofTopGuard. The new synthetic underlayments seal around nails, have the nailing patterns printed on them, are lighter, wider, and roll flat so they go up faster and cheaper.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I don't feel it's healthy to keep your faults bottled up inside me.
Thanks for the reply.One contractor that quoted my job is proposing using exactly what you describe - a material that has the nailing pattern on it. That contractor said that it is a breathable membrane.Another contractor is proposing using the fiberglass felt. He specifically stated that the felt holds water and that concerns me since it sounds like that could lead to more problems than the material that the other contractor is proposing. My wife and I felt that this contractor was somewhat shady as he did not directly answer our questions, but rather talked around them.
Edited 11/4/2008 1:32 pm ET by wiyosaya
Wait - Breathable? The underside of the roof deck needs to be breathable unless it is a "hot roof" that is packed with insulation. The top side of the deck needs to be water tight like a fish tushie.Rebuilding my home in Cypress, CAAlso a CRX fanatic!
Tu stultus es
Do those underlayments seal around nail holes? I thought that was a property mostly exclusive to ice & water shield.*Edited for poor grammar
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Edited 11/4/2008 1:38 pm ET by JonBlakemore
Does those underlayments seal around nail holes?
Those does not.View Image
Dang, you beat me to it.I was originally going to ask only about RTG, but then I looked at the Titanium site as well and decided to make my question inclusive. Of course, I didn't check my subject verb agreement.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
As it is plastic, the nail just stretches the plastic after the initial puncture at the tip. Felt paper tears slightly there. We're only talking about microscopics here, of course. I&WS, and other bitumin like layers reseal by regluing themselves to and around the fastener with heat.
The synthetics aren't as good a seal as the bitumin.Rebuilding my home in Cypress, CAAlso a CRX fanatic!
Tu stultus es
I highly recommend using a felt replacement like Titanium or PermaFelt.
It's durable, covers faster, is safer to walk on (doesn't tear as easily), it's rated for up to three months uncovered, and it's lighter. It's also only a little more expensive than 30# felt.
I prefer to fasten it down with cap nails rather than staples, as most brands are not "self-sealing".
__________________________________________________________________
I have cdo.
It's like ocd, only the letters are in alphabetical order like they're supposed to be.
http://www.truenorthcarpentry.net
Edited 11/4/2008 1:55 pm by True North
It's also only a little more expensive than 30# felt.
Titanium and Permafelt are slightly cheaper than #30 felt here. And the labor to install the synthetics is certainly less. View Image
Amazing. It was running at $120 for a 10 square roll in my area (MI) before I moved.And you're right, labor is way less._______________________________________________________________
I have cdo.
It's like ocd, only the letters are in alphabetical order like they're supposed to be.
http://www.truenorthcarpentry.net
That's about what it costs now. #30 felt is $25/roll.View Image