Replies

1. 
   maverick | Jun 14, 2005 12:57pm | #1

   How dry do you need it? How long do you reasonably want the building to last?

   Unless those overhangs go all the way to the ground those soffits are gonna get wet with wind driven rain. Same for the siding

2. 
   csnow | Jun 14, 2005 07:30pm | #2

   Wind-driven rain.  Felt is pretty cheap stuff.

3. 
   tyke | Jun 15, 2005 04:46am | #3

   you been watchin tommy silva again? lol  i saw tommy roof his own brothers house(that burned down) and he said you didnt need tar paper because the roof was something 10:12 or greater pitch. it really made me angry. no roofing manufacturer has ever said it was ok not to use underlament to my knowledge. also voids any warranty that there may be.

   tyke

   Just another day in paradise

1. 
   Framer | Jun 23, 2005 08:15pm | #9

   "i saw tommy roof his own brothers house(that burned down) and he said you didn't need tar paper because the roof was something 10:12 or greater pitch. it really made me angry."Believe it or not, but when I was framing houses in Cape Cod back in 1985 not one house did I see an tarpaper being used. I was baffled back then and was told you don't need it. It didn't matter what pitch the roof was.Joe Carola

1. 
   mbdyer | Jun 24, 2005 05:34am | #10

   If I put anything ontop of sheathing or underlay, it gets paper.  I'm still on the fence with Tyvek and such, they suck once wet, but I've seen hundred year old 30# hold up to a tearoff and then overlay with 15#.  Is that 45#?  If I&W was cheaper I would wrap a house with it.  Anyone who says felt is unneccassry underneath shingling or siding is just trying to cheap out on a job they underbid.  Sure on a steep pitch insome climate zones most of the water just sheds off the roof.  But what happens during the "unseasonably hot and humid" summer when a Nor'easter hits and all of the celing sheetrock nails pop?  Or worse?  Wow, that 150$ in material and  four hours of crew labor seems less, unless you enjoy small claims court cases and don't care what the BBB rates you as...

2. 
   rez | Jun 24, 2005 10:35pm | #11

   No paper!

   If I didn't know you guys better I'd swear you were pulling my leg.

    

    

   A person with no sense of humor about themselves is fullashid 

1. 
   Framer | Jun 25, 2005 01:20am | #12

   I'm serious. Shingles nailed right to the roof with no tarpaper. When I moved back to NJ and told everyone they thought I was joking. I seen a roofer/goon lay tarpaper vertically once and I'm not pulling your leg.........Joe Carola

1. 
   blue_eyed_devil | Jun 25, 2005 02:43am | #14

   I've seen entire subdivisions done with vertically layed paper. As far as I'm concerned, it's just as good vertical as horizontal.

   If someone can tell me what the paper actually does after it is peppered with ten thousand holes, I'll be impressed.

   edit: historically the paper sealed the air gaps that occured in the rough sheathing. Paper was also a necessary component when used with cedar shingles because they would shrink in the hot dry season and needed some rain to seal them back up.  I think that paper is just one more of those components that keeps getting installed becaue grandpappy did it that way.

   blue

    

   Edited 6/24/2005 7:45 pm ET by blue_eyed_devil

2. 
   mbdyer | Jun 30, 2005 02:00am | #15

   paper was used to dry in roofs historically when roofs took longer to finish.  Cedar shake or split slate without the benefit of nail guns, power ladders or cranes took longer to install.  Same with asphalt shingles once they'd become standard.  The old 30# felt when run properly would keep the building dry until the final roofing was done allowing the interior trades to keep working.  With the advent of staplers and pneumatics, felt went down to 15# and still worked well.  Eventhough the felt didn't serve as the roof for long, it was found that felted roofs often performed better, isolating the roof sheathing from condensation on the underside of the roofing material, despite ten thousand holes until the nails rusted, thus the aborted attempt to use aluminium nails that didn't rust.  This then backfired when homes were sealed better with better performing windows and house wraps; the water vapor would migrate up to the roof sheathing and work at it from below.  This was exacerbated by improperly vented bathrooms with the "new" fan vents, dryer exhaust and the like.  Now we have the "cold roof" practice, where the roof is allowed to acclimate to exterior temps and humidity and simply shield the interior from precipitation.  The attic floor now became the thermal barrier.  So now the roof is in a similar situation on a "cold roof" as it was back with drafty uninsulated homes and will again perform better.  Using asphalt felt seperates substrate from finish as they each have different R-values and when you have two substances touching at different temps, water condenses on one as in a rainstorm when a warm front hits a cold air mass.  This is also why wood that is capped can quickly rot away underneath the protective metal.

   If I could sell I&W for the whole roof, I'd gladly use it.  The current  I&W specs are a compromise of effecicay and economy.

   As far as running felt vertically, the problem with this is sidelap.  Vertical felt is often only sidelapped 2-4".  Most every shingle manufacturer and town code dictate that sidelaps are a minimum 6-8", often a foot.  If you sidelap vertical felt at least that, starting away from prevailing winds and layering towards, vertical run felt should perform as well as horizontal.

3. 
   blue_eyed_devil | Jun 25, 2005 02:41am | #13

   Framer, I've done a few roofs for myself and never used paper under the shingles. Felt is definitly over-rated. If the water get through the shingles with the hidden nails, why does anyone think it wont find its way through the paper that has ten thousand nail holes in it?

   If someone advocates putting ice and water shield under the entire roof, then I'll accept that idea because the nail holes self seal.

   blue 

4. 
   piko | Jun 15, 2005 07:56am | #4

   Just think of the wrap as the thing that stops water getting in. The siding is there to stop the sun breaking it down.

   cheers

   ***I'm a contractor - but I'm trying to go straight!***

1. 
   DustynLefty | Jun 22, 2005 07:25pm | #5

   Yup, it will do a better job of keeping out the wind and the rain and maybe biting bugs.  Someday somebody will want to put a heater in it while working on something.  Stapling up the felt in the beginning is quick and cheap, and will be done long before you suddenly realize why it would have been a good idea.

   Just my opinion though,

   D&L

2. 
   JeffBuck | Jun 23, 2005 05:14am | #7

   excellent answer!

   Jeff    Buck Construction

    Artistry In Carpentry

        Pittsburgh Pa

5. 
   BossHog | Jun 22, 2005 08:49pm | #6

   Has anyone mentioned wind driven rain yet ???

   When I was a kid, my family had trouble keeping food on the table.
   Then we realized it was because the table was just poorly made.

6. 
   jimz | Jun 23, 2005 04:29pm | #8

   Around here (NE Ohio), most new construction use Tyvek or similar products on all heated surfaces before siding.  I agree with Piko that the paper or wrap's primary purpose is to serve as a "water plain"... which must mean that water doesn't penetrate the the siding on garages or unheated gable plains (sure).  The best analogy for house wraps that I can think of is that of a new nylon wind breaker; i.e.  the wind breaker stops the rain from wetting your shirt, but breathes enough to allows perspiration to evaporate.