Give ya some background……….
I live in a small log home I built 6 years ago. Now, in the process of adding 24×40 garage with full bedroom and bath above, connecting to existing log home. We are in the sheathing stage and the carpenters are going to leave for a month or so to work on another project. I am almost finished milling siding out of rough sawn 1×12’s to mimic the log exterior. No paper of any sort is on the building yet.
I have had the talk with the carpenters about using/not using Tyvek or using plain ole tar paper as a moisture barrier. They say that they have been using Tyvek and like it. These are a bunch of “good ole boys”—the kind you think it would take a long time to switch over to modern engineered building products. But they also use on Advantech flooring, and OSB for roof and wall sheathing. So I am gonna use Tyvek.
Questions……..
1. Wasn’t there a discussion long ago about leaving Tyvek exposed to the elements for longer than 2-4 weeks and then the stuff begins to breakdown?
2. What about installing Tyvek in the Gable ends where this is Attic space? Why place it there? Soley for a Moisture barrier?
Gimme some ‘sperience on Tyvek.
Replies
your correct about tyveck not holding up to the sun, this is why I use typar. I have left this exposed for up to six months with no degrade.
yes do the gable ends, start the bottom and work up, just like siding so the wrap will shed water.
tyvek rates the best in the tests of all the HOUSEWRAP PRODUCTS... almost as good as good old 15# felt, which is what we went back to after about 4 years with different housewraps... and we use Advantech too !Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike,
What do you use for the walls and roof? Where do you work in RI?
Turtle boy
walls we use 15# felt...
roofing we use Roofer's Select... or some of the new 10 sq rolls of Roof Top...
we work mostly Newport county, Jamestown, & N.K.Mike Smith Rhode Island : Design / Build / Repair / Restore
I'm with Mike, we quit using house wraps too and now use "Grade D" tar paper. It's not your father's tar paper, double layer, more breathable, and made for this purpose.
Steve
Steve , I called the lumber yard to ask about "grade d " tar paper , and they didnt know any thing about it. I didnt think you were joking . Would you set me straight on this ?
Tim Mooney
Tim, sorry I haven't replied sooner. I will have to check to find who manufactured our "Grade D" tar paper (this is a 60 min. tar paper, which has to do with how long it holds out water under specified conditions) , but it should be something that your lumber yard should be able to ask their supplier about.
For all who are interested, there was a study done at the Univ. of Mass. at Amherst, by Paul Fisette in '99 called "Housewraps, Felt Paper and Weather Penetration Barriers that explains the problem pretty well. The bottom line is his final statement that he used felt paper on his own house. Sorry I don't have a link posted, I'm just not that computer literate, I guess.
Steve
On a un-heated space I wouldn't use anything but good old tar parper. With a good job stapling and lathing it down you can weather it for a long time. (A lot less expensive too)
You have to be very carful with both tar paper and Tyvek on heated spaces and would use nothing but breathableTypar. I have seen ( and heard about) some real horror stories in walls that are covered with tar paper. A dew point was created in the wall and the moisture could not get out. The house rotted from the inside out!!
I would like to know more about this phenomenon if anyone knows about it.
Cushing, Maine
eli... BS... 15# felt is every bit as breathable as typar and tyvek... if there is a dew point in the wall it ain't because there is 15# felt under the siding.... c'mon....Mike Smith Rhode Island : Design / Build / Repair / Restore
Anyone see any issues with #30 these days? My thought process is that the old 15lb felt had 15lbs of tar per square (as far as I know) now that #15 is not the same as the old 15lb felt, therefore to get close to the 15lb of old you need to use #30. Any one see any reason not to use the #30......price isn't a concern on this part of the job (I never thought I would say that).
SJKnow a little about alot and alot about little.
#30 is all I use.
For a roof deck, or wall sheathing, #30 is my choice.
Dew point created because of "tar paper"... never heard of that one before. Never seen anything like that either. There must have been other issues involved. James DuHamel
J & M Home Maintenance Service
Thanks James
I figured most people chose #15 for the cost, I figured #30 was fine to use. I wanted to get closer to true 15lb felt.
SJ
Know a little about alot and alot about little.
I no longer use Tyvek at all. Only 30# felt. It's harder to apply and therefore more labor, but in doing a lot of renovation work the old paper is almost always intact. We've seen some pretty interesting 10-YO tearoffs where the Tyvek was decomposed by surfactants in lumber products, particularly unprimed cedar (which is now recognized as a no-no). But I'm troubled by that - if it is affected by certain wood by-products then what are the implications over time? Since Tyvek passes moisture but not liquid, if there is a failure and water gets behind it you can get rot. If it fails to breathe under any circumstances you then have a wrong-side vapor barrier. But then, I'm not a builder ...T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Sorry Mike I didn't mean to get your shorts all in a bunch.
I must be missing somthing here, give me the ABC's, as you understand it, about Tyvek and Typar. I thought that Typar could breath like Gore-Tex and Tyvek wouldn't.
And I also didn't think that tar paper was "breathable"
Further, I never said that the tar paper caused the dew point, I just meant that it did not allow vapor to escape. The inside of that wall was pretty soggy!
P.S. I'm not a builder so I'm not up on these things. I am just curious.
Cushing, Maine
Edited 7/18/2002 7:03:09 PM ET by Eli Ellis
not in a bunch or even upset.... i just stay current on building science.. and one of teh current things making the rounds in the last two years or so is that the housewaraps are not outperforming good old 15# felt....
and even i knew that 15# felt will pass vapor but not water... so...
when i hear claims that a wet wall was caused by felt instead of using typar or tyvek... i tend to think someone is blowing smoke...
a wet wall is wet because the moisture source is not being controlled..
but hey, whadda i no ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Tyvek and Typar are not moisture barriers. That is the job of your interior vapour barrier. These things ar eoften mixed up.
Tyve and Typar air barriers and help prevent air pentetrations into the structure. Moisture develops when warm air hits cold air. This would be a failure of the insulation and vapour barrier
duh.... ya don't say ? tyvek, typar & other "air barriers " are overrated & overpriced..
they react with surfactants...
now you want to drag this discussion down into the bottomless pit of interior vapor barriers... i sure wish fredl was heah to set u strait...oh , well... nevah mine...Mike Smith Rhode Island : Design / Build / Repair / Restore
Tyvek makes good envelopes and jumpsuits for dusty work.
Typar makes good temporary covers for building materials stored outside.
Impregnated felts are good house wraps.
joe d
Tyvek is advertised as a moisture barrier - and that is part of the problem - if water (not vapor, but moisture) gets behind it you're dead.T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Seems to me that the more high-tec the house wraps get the more we have issues like black mold,indoor air quality,etc.Felt or rosin(resin?)paper for me.Have had to argue my point with a few building depts.to get plans approved though.
Surfactanrts affect all building papers, Tyvek,Typar,others, and felt. They do not change the structural integrity of any of these products. They do however change the charateristics of water. Like soaps, surfactants make water "wetter". This is how dishes and laundry get clean. The amount of water that passes through any of these materials is a much greater concern than percentage of change from original performance. Tyvek in its worst case senario will outperform building paper in water holdout. In addition, building paper is not very permeable at all (around 5 perms,code minimum). Most plastic housewraps are at least 3 times more permeable and again Tyvek leads the group (58 perms).
I provide seminars on Moisture Management on a regular basis to architects, builders, code officials, and specifiers regularly in your area. I would like you to be an invited guest. It may do well to dispell some of your misconceptions.
buck... most of my info on the testing is from JLC about a year ago..
since we do dens-pak cellulose... the air infiltration claims of Tyvek & other housewraps do not interest me..
i am not concerned about the perm rating of felt VS tyvek since our wall sections are not at risk..
let me know when and where you wil be giving your seminars as i'm always eager to learn..Mike Smith Rhode Island : Design / Build / Repair / Restore
I don't recomend using Tyvek or Typar behind wood siding unless you back prime it first. House wraps allow moisture to escape your home (and more moisture than you may think does get expelled daily) so you need to protect the bare wood on the back side.
Not be a smart aleck, but.......
What do you think DuPont's reply would be to this statement? I am kicking myself for supporting DuPont, No. 1, because I am not a Jeff Gordon fan, No. 2, because there are numerous reports about DuPont Factories destroying the enviroment "under the rug".
I don't think anybody can say tyvek is better or worse than tar paper and vice versa. It comes down to personal preference. I in my own personal experience I wouldn't say one is better than the other. I have seen mold in behind tar paper and that was only because the interior air was escaping from around the window collecting under the tar paper and forming mold. I haven't seen any trouble so far with tyvek but that doesn't mean it hasn't happened. We can argue till we are blue in the face about it but in the end the firm believers in both camps will think they are right. Use what you want and move on.
A moderately large, single story commercial building is being constructed that I go by occasionally. The last time I went by, they had covered the OSB sheathing with Tyvec and were then installing metal siding (continuous sheet from foundation to roof). Is this standard procedure? Seems like you would be more apt to trap moisture behind the the siding with Tyvec than without it. What is a bigger risk, rust behind the siding with Tyvec or damage to OSB without it?