Replies

1. 
   skids | Jul 15, 2003 03:36am | #1

   i am not a big fan of the tyvek, i understand that it is an air barrier, not a moisture barrier. this may be an oversimplified version of what it really is, and it may not even be correct. how can it keep out air, but let moisture through? i too have some confusion about what exactly tyvek does, and the only information on it is from dupont, and they are trying to sell it, so i am sceptical. but i do think that if the tar paper, or 15# or 30# asphalt impregnated felt paper, was there for 40 years and the siding shows no damage or rot from the inside, and the studs also inside the tar paper are in good shape i would stick with the tar paper. if it ain't broke don't fix it. also i would certainly open up a few areas to inspect, and add a new layer of paper unless it is in pristine condition after removal of old siding. i don't think it neccesary to remove old paper as long as it is lying flat and there is no sign of rot, no matter what else you do.

2. 
   bill_1010 | Jul 15, 2003 05:40am | #2

   stick with tar paper.   Its time proven.  

3. 
   andybuildz | Jul 15, 2003 02:21pm | #3

   Was watching some home show the other day and they were talking about the house wrap (Tyvek). The contractor was speaking about it allowing the moisture to escape but who knows...I'm wrestling with the idea of using it myself...time may prove felt paper to work but time may also prove house wrap is better ...who knows.

   Kinda worries me to wrap poisens in my house but the speaker on the TV show I was watching made a point to say it lets out poisonus vapors..but who knows.....ugh

   BE well

            andy

    

    

   In his first interview since the stroke, Ram Dass, 66, spoke with great difficulty about how his brush with death has changed his ideas about aging, and how the recent loss of two old friends, Timothy Leary and Allen Ginsberg, has convinced him that now, more than ever, is the time to ``Be Here Now.''

   http://CLIFFORDRENOVATIONS.COM

1. 
   BillHartmann | Jul 15, 2003 06:10pm | #8

   " but who knows.."

   Paul Fisette.

   He has done several article in JLC on this and some lab test. And they are on the UMas web site.

   http://www.umass.edu/bmatwt/publications/by_title.html

   There might be some others, but look at the Housewrap and Leak Housewrap articles.

   I also susepct that there is lot of info on buildingscience.com

   Mongo I am glad to see you answer nic's question. Everyone else wanted to get into the tar paper vs tyvek arguement without answering his question about using one if there was none orginally.

   Now I am not a building pro so I hesitate to answer these kinds of questions. But my very limited experince, reading Paul's articles, one of the Building Science books, and my engineering background all agree with what you are saying.

1. 
   Mongo | Jul 16, 2003 07:35am | #12

   Thanks for the kind words, Bill.

4. 
   River19 | Jul 15, 2003 02:58pm | #4

   I resided last summer and after a bunch of research and plenty of searching through this site (this topic rears it's head a few times per year on here) I went with #30 tarpaper.  There is also some confusion from what I remember between #15 and 15lb tarpaper.  #30 tarpaper is as close as you will get to 15lb tarpaper now.  As far as I have seen 30lb (as in 30lbs of tar per whatever....like 100sq ft or something) isn't available readily anymore.

   The way I look at it is that there are houses out there built way back in the day that were built using tarpaper and the sheathing looks fine.  Tyvek doesn't have that history yet.  Plus there are some studies that the tannins (sp?) in cedar can eventually damage the Tyvek.  Then again there are probably studies proving that study wrong as well.

   It becomes a Ford vs. Chevy thing, people are in either camp for the most part.

   My $0.02.

   SJ

   Know a little about alot and alot about little.
1. 
   edwardh1 | Jul 15, 2003 03:38pm | #5

   whats needed is an independant study. maybe someone other than Dupont has done one?????????

   I am a a tar paper fan

   but its instinct.

   Builders might like tyvek cause of bigger pieces less seams

5. 
   Mongo | Jul 15, 2003 04:33pm | #6

   As others have noted, tar paper has changed. Used to be 15# (15 pound) or 30#. Now, with less product in the paper, it's #15 (Number 15) or #30. Sneaky little marketing dweebs.

   There is a "newer generation" or tar paper, along the lines of Roofer's Select. Has a bit of glass fiber reinforcement in it to resist tearing, halps it lay flatter as well.

   I wouldn't use spun poly housewraps under, in direct contact with, sidings like cedar and redwood.

   On your house, if you find an existing layer of tar paper, I'd pull it off and replace it. Removing it alllows an inspection of the sheathing and flashing, etc. I'd use a NEW layer of tar paper even if there is nothing under your existing siding. Material cost and labor to install are negligible.

6. 
   Planeman | Jul 15, 2003 05:35pm | #7

   Nic,

   Your new to this game, forget what these "experts" are saying. You gotta go for the "cool" factor and hands down Tyvek looks cooler than tar paper, but only until the sideing goes up. I'm surprised thatsomebody like Undewriters Laboratories hasn't done a performance study of this product.

   Experienced, but still dangerous!
7. 
   TommyB12 | Jul 16, 2003 12:33am | #9

   I think jlc had and informative article on this recently.

   I'm a tarpaper guy.  But it depends on what you are trying to accomplish.

   Tom

8. 
   EricS | Jul 16, 2003 05:26am | #10

   I am currently doing what you have signed up to do - mine is a 1940's house in Silver Spring, MD.  The "tar paper" that was applied in the 40's was about the equivalent of what I see as 15 lb paper today.  It was in fair shape but removing the existing wood siding made it worse.  I am removing it all.

   As others have said this gives you the opportunity to inspect the sheathing (probably 1x6 or 1x8 boards) and correct any looseness or, as in my case, some cupped boards (disk sander).  I applied 30 lb tar paper prior to the fibercement because I wanted to give the boards a little more cushion.

   I believe you would be on the right track by applying 30 lb paper over the sheathing.

   Eric S.

9. 
   GUNN308 | Jul 16, 2003 07:19am | #11

   Of the thousand or so houses, in the northeast I opened by removing & replacing the siding to blow in insulation, the majority of wood sided houses had rosin paper over the sheathing not tar paper, but I never saw a problem beneath either other than problems caused by bad techniques and flashing details. Back when most of these houses were built the paper was use to block exterior air infiltration I just thought that rosin paper would allow the house to breath a little easier and still block the breezes. Not finding any research to back up this theory this is just my 2 cents worth, I use rosin paper behind vinyl siding because I worry about bleed through from tar and often times I can't tell what there is for a vapor barrier on the interior.

1. 
   dthodal | Jul 16, 2003 03:43pm | #13

   I still prefer using rosin paper for building paper under wood siding. Like you I have found little study on it's use, but here are my observations.

   Rosin paper today is less thick and less impregnated with rosin than paper used even 50 years ago. Essentially rosin paper is a satuated pa[per much like felt except using pine rosin rather than a petroleum based product.

   Protected from exposure rosin paper can handle repeated wet/dry cycles. But with exposure will deterioate much quicker than felt.

   The big advantage to rosin paper over felt and tyvek, is it's ability to wick moisture, dispersing it over a greater area to allow quicker drying. Also, it will wick moisture from the wood siding and/or sheathing thus promoting quicker drying of the area.

   I remember seeing and using 15 felt at all casing and corner board areas in the attempt to improve the weather resistance and rot resistance of those prone areas. However I also remember finding alot of rot there as well. My thinking on this has evolved to the thoughts that felt may have been complimentary to the problem. Felt like rosin will absorb moisture and becomes satuated, but it takes much longer to absorb and eventually dry out. Also because it absorbs moisture more slowly, it allows the moisture to be absorbed more into the wood increasing the drying time all around. My experience leads me to believe that this longer drying time may contribute to the problem of rot and decay.

   I still like using rosin paper, though I have had a harder time convincing the building department and clients. The plastic housewraps have done an excellent job of selling their products and sloppy /poor siding choices / installation has certainly reinforced their sales pitch. If I do not use rosin, then I would use #15 saturated felt.

   walk good

1. 
   Davo304 | Jul 17, 2003 11:02am | #14

   I too have seen both felt and rosin paper used, and in these instances, when removed, proved to be good protectors for the wall sheathing. Little or no rot was ever found. I used 30# felt last year when installing vinyl siding on my garage addition.

   Three things about Tyvek that I really dislike....

        1. Cost....just plain too damn expensive.

        2. longevity...Claims are being made ( not all are substantiated yet) that certain materials that rub against Tyvek causes chemical reactions and that Tyvek loses it's form...it slowly disintegrates. Supposedly dirt, will clog it and also render it useless..."supposedly"

       3. Not sure it works at all.......When working around grease pits and other dirty places in the steel mill, we were issued Tyvek cover-alls...these were "paper suits" that after use, could be thrown away. These suits were the EXACT SAME MATERIAL as used for wrapping homes. These suits ALWAYS held moisture in next to our bodies. On a fairly hot/humid day, a person's clothes would be totally soaked in 20 minutes or so. If you wore one of these "white-suits" as a rain coat, you still would be almost as wet as if you had no protection at all...the wetness coming from the suit's ability to cause you to perspire. Unless you kept your suit unzipped, in order to allow some airflow, you were certain to get soaked.   So, this being the case, seems to me that Tyvek would promote rot by holding moisture in, rather than protect against it by allowing moisture out...least that was how the  white suits always functioned.

   Tar paper is time proven...I'd stick with that.

   Just my 2 cents

   Davo

1. 
   BillHartmann | Jul 17, 2003 07:00pm | #15

   "These suits were the EXACT SAME MATERIAL as used for wrapping homes."

   Now do you know that they are EXACTLY THE SAME MATERIAL AND THE SAME PROCESSING so that they have the same characteristics?

   Did you do an lab tests on the two products.

   You can by a Whirlpool refigerator and you can by a Whirlpool central air system, but that does not mean that the same refigeration parts are used in them.

1. 
   skids | Jul 19, 2003 09:59pm | #16

   if you turn those protection suits inside out then you don't sweat at all!, and they keep you dry! after reading all these posts on the subject i have decided the best way to go is with the tyvek but to install it backwards