15# vs 30# Felt Paper

Reply

  #1  
Old 10-30-15, 02:43 PM
Member
Thread Starter
Join Date: Mar 2013
Posts: 127
Received 0 Votes on 0 Posts
15# vs 30# Felt Paper

i have a low slope roof, the shingle manufacture that i'm using says to doubling up on felt underlayment but it doesn't say whether to use 15# or 30#..I would think 2 15# papers would be the same as 1 #30, so if u se 30# there is no need to double up
 
Sponsored Links
  #2  
Old 10-30-15, 02:50 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,376
Received 9 Votes on 7 Posts
What is the current pitch of the roof? Did it previously have shingles on it?
 
  #3  
Old 10-30-15, 02:51 PM
Member
Thread Starter
Join Date: Mar 2013
Posts: 127
Received 0 Votes on 0 Posts
its an new patio roof...2.5/12 slope..im in California so hardly any rain
 
  #4  
Old 10-30-15, 03:26 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,376
Received 9 Votes on 7 Posts
I fail to see how double felt will make a difference, you still are putting the same holes through the pape when you nail it up. Send us a link to the shingle you want to use so we can verify what you are reading. I just did a fairly major repair on a low pitched shingled roof where the nails were placed too close to the edge of the overlap. Made a mess and a lot of rot. I replaced the felt with ice and water shield which is a nail self sealing membrane in the problem area.
 
  #5  
Old 10-30-15, 04:17 PM
Member
Thread Starter
Join Date: Mar 2013
Posts: 127
Received 0 Votes on 0 Posts
Page 3, felt is overlapped 19", to create double :

http://www.owenscorning.com/NetworkS...structions.pdf
 
  #6  
Old 10-30-15, 04:32 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,376
Received 9 Votes on 7 Posts
15# felt is standard. You will be in better shape with these shingles than the standard 3 tab ones that I did my repair on. Although, Ice and water shield for a starter and the rake would be my requirement in addition to the felt paper.
 
  #7  
Old 10-30-15, 05:35 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 23,810
Received 289 Votes on 263 Posts
Doubling up is silly but its sometimes a code requirement. On a low slope it is more important to overlap the paper more than the usual 2". Do whatever the local building code or mfg requires. I agree about the ice and water shield but depending on where you are in CA that might be a bit overboard.
 
  #8  
Old 11-06-15, 03:25 PM
Member
Thread Starter
Join Date: Mar 2013
Posts: 127
Received 0 Votes on 0 Posts
Post

It turns out it was code required so we did 2 layers of 15# felt paper..No i came across a different problem I dint think about.

The new patio roof ties into the house roof by going in 3 feet. So i removed the first 3 feet of shingles from the house so can tie in felt paper. However I just noticed that the roof has 3 layers of shingles ....Can I just remove the top layer, tie-in the felt paper by putting it on top of the other 2 layers of shingles and then re shingle the top layer?
 
  #9  
Old 11-06-15, 04:25 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,376
Received 9 Votes on 7 Posts
With that many layers, I would seriously want to see what shape the roof decking is in. It has never really been inspected just an overlay of a new layer. AND the low pitch means they may have had problems in the past that a re-roof took care of.
 
  #10  
Old 11-06-15, 04:52 PM
Member
Thread Starter
Join Date: Mar 2013
Posts: 127
Received 0 Votes on 0 Posts
I already took 3 feet of the tripple layers of shingles down to the deck. Surprisingly the wood looks better then most of the wood at home depot. Rafters and sheathing are in perfect condition. BTW the slope on patio roof will be 2.5/12 but the house is 5/12..I just think they didn't want to pay the fees to throw away the old stuff...House roof like 10 yeas old. But in 5-10 years when I have it redone i will remove everything..
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: