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Roofing Felt

tpmcnichol | Posted in General Discussion on September 2, 2004 01:33am

Dumb question of the day:  When people refer to “#30 felt” for a roof…is this the same thing as the roll of tar paper at Home Depo?

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Replies

  1. Leucas | Sep 02, 2004 01:41am | #1

    No, it's not the same. One is a felt-like absorbent paper saturated with sticky black crap and the other is actually used between the plywood and shingles on a roof.

  2. User avater
    Sphere | Sep 02, 2004 01:42am | #2

    yup

    the thicker stuff is 30, thin is 15

     

    Spheramid Enterprises Architectural Woodworks

    Repairs, Remodeling, Restorations. 

  3. User avater
    IMERC | Sep 02, 2004 01:42am | #3

    yup...

    There's 15#felt too...

    Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....

                                                                       WOW!!!   What a Ride!

    1. User avater
      Sphere | Sep 02, 2004 01:58am | #4

      we forgot the 90 lb stuff.. 

      Spheramid Enterprises Architectural Woodworks

      Repairs, Remodeling, Restorations. 

      1. Shep | Sep 02, 2004 02:23am | #5

          Actually saw a roof once where they used the red rosin paper under the shingles.

          Scratched my head for awhile on that one.

        ( Imerc- I promise not to think about it)

        1. User avater
          IMERC | Sep 02, 2004 02:32am | #7

          I've seen that one done before...

          Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

          Edited 9/1/2004 7:51 pm ET by IMERC

        2. JohnSprung | Sep 03, 2004 01:54am | #37

          > Actually saw a roof once where they used the red rosin paper under the shingles.

          That's SOP under copper, mainly as a bond breaker for expansion and contraction, also as a chemical barrier.  If the shingles weren't copper, it sounds like a mistake.  It may be cheap, but it's sure no fun to walk on -- too slippery.

          -- J.S.

      2. User avater
        IMERC | Sep 02, 2004 02:32am | #6

        He didn't ask so we don't tell 'em about 120 either...

        He got a bonus with the 15#..... He'll be happy...

        Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

        1. Piffin | Sep 02, 2004 02:41am | #8

          There is also 33#, 43#, 60#, and 80# for various fun ctions 

           

          Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          1. User avater
            IMERC | Sep 02, 2004 02:52am | #9

            Ted is not going to be happy about this....

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

          2. User avater
            IMERC | Sep 02, 2004 02:54am | #10

            And the line of Grace....

            All this and nothing has yet been said about house wrap preferences, or that it's gotta be put on with your screws...

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

          3. UncleDunc | Sep 02, 2004 03:22am | #13

            >> There is also 33# ...

            Not to mention 45 and 78.

          4. seeyou | Sep 02, 2004 03:58am | #14

            And if you roll out #33 at the same speed you would #45, you sound like Alvin and the Chipmunks................. Oh, Dave..........

          5. Piffin | Sep 02, 2004 04:03am | #15

            Your inner DJ is crying to be let out... 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          6. User avater
            IMERC | Sep 02, 2004 04:50am | #16

            somebody confusing vynal with felt????

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

  4. Piffin | Sep 02, 2004 02:56am | #11

    Ted, I don't know what they sell at HD, but originally the idea of the number indicated the pounds per hundred square feet of coverage. The basic tarpaper was a sixty pound roll of felt rag saturated with asphat to keep it more or less water resistant. that sixty poud weight roll would have 4323 square feet of material and allowing for the waste in laps, would cover just about 400 square feet of roof area. 60# over four squares gives you fifteen pounds persquare.

    Thirty pound paper was twice as haevy and covered only two squares in a sixty pound roll.

    Then in the seventies, asphalt got pretty expensive - someting about an energy crisis and oild embargoes and all that - so they started trying to produce a roofing underlayment that used less asphalt. I remember a 20# rated as thirty but only marginally tougher than 15#.

    Anyway, after a decade or so, they all more or less settled on the idea that 15# now means number fifteen instead of fifteen pound, and on up the line for various weights. Some brands are better than others, but none are equal to what you could get way back when... I have seen some felt that you could barely tell had any asphalt at all - it looked almost like dark resin paper. One advantage of them using less asphalt is that the rolls are less likely to stick to themselves. it used to be a problem trying to unroll on a hot day without tearing them up.

    As a general rule, 15# is the quickie version to use on a new smooth sheathing if you are going to cover it with shingles immediately. Leave it long and the wind will shred it more often than not.

    30# is what you look for on higher quality jobs or on re-roofs, where an overnight shower could spell disaster with 15#.

    The heavier weights are for hot asphalt roofing on lower pitched roofs.

    Here's a clue for everyone out there - never store or ship tarpaper laying down. It should always be stood on end. That saves damage to the roll and lets you unrol it easier and it lays smoother. A yard that stores, delivers, and stacks the rolls laying down has no concerns for the quality of the products they sell or the convenience of the builders using the product.

     

     

    Welcome to the
    Taunton University of
    Knowledge FHB Campus at Breaktime.
     where ...
    Excellence is its own reward!

    1. DANL | Sep 02, 2004 03:13am | #12

      Well, I don't know about Ted, but I appreciated your thoughtful reply. Learned a lot about roofing felt that I sort of thought I knew, but didn't really.

    2. FastEddie1 | Sep 02, 2004 05:26am | #17

       4323 square feet ... would cover just about 400 square feet   Help me Pif ... how do you go from a 4000 sf roll of material to 400 sf of roof area?

      Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

      1. Piffin | Sep 02, 2004 05:29am | #18

        typo

        432 sq ft 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

        1. FastEddie1 | Sep 02, 2004 05:37am | #19

          That sounds much better.  I was imagining a huge overlap.

          Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

      2. User avater
        IMERC | Sep 02, 2004 08:15am | #22

        10 layers???

        Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming....                                                                   WOW!!!   What a Ride!

        1. FastEddie1 | Sep 02, 2004 03:09pm | #23

          10 layers???  Well, you know those anal folks in Maine ... they build things to last.  Wonder if they had to drill pilot holes for the nails?Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

          1. Piffin | Sep 02, 2004 07:19pm | #24

            If yer gonna live in a tarpaper shack, at least make it an authentic tarpaper shack!

            ;) 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

    3. AXE | Sep 02, 2004 06:12am | #20

      The roofers just finished up my roof yesterday (45 squares). They only use 15# felt, he says the 30# is a total waste.  However, the trick he throws at you is that he uses felt with fiberglass in it so it won't really tear at all (HD doesn't sell this stuff).  In fact I tried to rip a little piece off one day by laying a 2x across it and tearing it and I couldn't even get started.  The framers complained of the itching (they ran the paper).

      The tar paper was up there a good 2-3 weeks and we survived several large rains (NC - we got a few tropical storms coming through), with no ill effects.  Again, I think the key is in that fiberglass stuff.

      MERC

      1. Piffin | Sep 02, 2004 06:38am | #21

        Yeah, there are all kinds of tricks and alternatives. I can lay 15# and it will stay there for three weeks or so, but I was advising a DIY so I wanted to serve his intresets.

        The best thing actually, and what I do now is use the RooftopgaurdII. It is easier because it is 5' wide, lays flat, and is stronger than FG sat paper. I don't worry about it staying put for three or four months 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

  5. User avater
    CapnMac | Sep 02, 2004 10:22pm | #25

    "#30 felt"

    The book answer is that is the "short hand" for:  asphaltic tar impregnated felt to an aproximate weight of 30 pounds per square yard.

    Felt fibers can be used to make "rag" fibre paper, so the term "builder's paper" (and "tar paper") survive to this day.  As previously posted, the numeric value refers to the amount of weight per yard, so 15# felt is thinner and lighter than 30# felt.  There are different uses for all of the weights.

    Some of the rolls from the "big boxes" seem to have recycled content:  craft paper glued up with shredded felt scraps with melted recycled road asphalt, all squeezed as thinly as possible to maximize profit while retaining a vague resemblance to the product label . . .

    Occupational hazard of my occupation not being around (sorry Bubba)
    1. User avater
      Sphere | Sep 02, 2004 11:16pm | #26

      if it was 30lbs a sq yrd ( 3 feet of a rolls length) I don't think I'd be able to carry a roll..the are 200 sq feet on a roll diveded by 9 sq ft...is 22.2222x 30 lbs = a 660 lb roll..

      Wanna try again? 

      Spheramid Enterprises Architectural Woodworks

      Repairs, Remodeling, Restorations. 

      1. Piffin | Sep 02, 2004 11:45pm | #27

        Lotsa typos in this thread, eh? 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

        1. User avater
          Sphere | Sep 02, 2004 11:50pm | #28

          thread?  I thought it was FELT?  30lb thread? must be fishing line?

          I'm confused.. 

          Spheramid Enterprises Architectural Woodworks

          Repairs, Remodeling, Restorations. 

          1. DANL | Sep 03, 2004 01:04am | #32

            Felt. Like in Junior high, asking a girl if her shirt were felt....

          2. User avater
            Sphere | Sep 03, 2004 01:25am | #33

            junior high? how 'bout yesterday at walmart? 

            Spheramid Enterprises Architectural Woodworks

            Repairs, Remodeling, Restorations. 

          3. seeyou | Sep 03, 2004 01:38am | #35

             how 'bout yesterday at walmart?

             

            I got a story about that. Ask me the next time you see me. I'd post it here, but Gabe Martel will delete it. 

        2. DANL | Sep 03, 2004 01:03am | #31

          Re: Lotsa typos: They're just seeing if you guys are payin' attention!

      2. User avater
        CapnMac | Sep 03, 2004 12:21am | #29

        Wanna try again?

        Lugging 30# felt up ladders, not, not really . . .

        I don't happen to have my ancient Building Construction textbook handy (wouldn't be handy even if I were at home <g>).  Maybe that's xx# the square.  I may have confused fabric weight, which is weight per yard, thus 16oz cotton is finer/lighter than 22oz cotton.Occupational hazard of my occupation not being around (sorry Bubba)

        1. User avater
          Sphere | Sep 03, 2004 12:40am | #30

          I'm guessin a 2 sq. roll of 30lb. weighs about 45-50 lbs. I just burnt through 10 rolls this summer..but I never weighed one.

          If it does weigh 60lbs..that would be 30lbs/sq. (100 sq ft) .. 

          Spheramid Enterprises Architectural Woodworks

          Repairs, Remodeling, Restorations. 

          1. seeyou | Sep 03, 2004 01:32am | #34

            If it does weigh 60lbs..that would be 30lbs/sq. (100 sq ft) ..

             

            You are correct, sir.

          2. User avater
            Dinosaur | Sep 03, 2004 01:38am | #36

            It's supposed to weigh 60 pounds, no matter what the weight number is on the roll. The fact it doesn't means the mfgrs have got their big fat thumbs on the scales, dang it! There oughta be a law....

            Anyway, around here (suspect down by you, too) 90# is also called 'roll roofing' and is sanded. Real fun to walk on, whoooooops!

            Dinosaur

            'Y-a-tu de la justice dans ce maudit monde?

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