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General => General Forum => Topic started by: hnash53 on April 28, 2010, 08:24:33 AM

Title: Tar paper vs. building paper (Tyvek and the like)
Post by: hnash53 on April 28, 2010, 08:24:33 AM
If I strip off the house siding and want to put up new paper before I re-side the house, is there still a war going on here in the forum regarding the use of tar paper versus tyvek or tyvek generics?

I've heard rumblings of a new product.

I have moved away from DRY Wyoming to WET Oregon.  And I am considering buying a small home I want to re-side with cedar shakes but will have to pull off the horizontal lap siding.

Several of you I know live in the wet Pacific Northwest.  What are your thoughts?

Thanks.

Hal
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: John_M on April 28, 2010, 09:51:37 AM
I would say that the majority of the people on this forum seem to choose tar paper over Tyvek.
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: bayview on April 28, 2010, 03:13:30 PM
Quote from: John_M on April 28, 2010, 09:51:37 AM
I would say that the majority of the people on this forum seem to choose tar paper over Tyvek.

   Yes, this has been discussed in depth . . .   Here is one of the topics/

http://countryplans.com/smf/index.php?topic=7579.0 (http://countryplans.com/smf/index.php?topic=7579.0)
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: Jeff922 on April 29, 2010, 09:45:52 AM
If you were sweating what would you rather be wearing Gore-Tex or a rubber rain coat?  I'd take the gore-tex (Tyvek); I want the moisture to be able to get out.  But there are two sides to this argument; it really comes down to perm ratings:

http://teachers.sheboygan.k12.wi.us/jgrunewald/houseproject/documents/HouseWrap.pdf
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: MountainDon on April 29, 2010, 10:37:32 AM
I see the above reply was amended while I typed...


GoreTex may not be a good analogy; or maybe it is.  ??? The first GoreTex fabrics had problems and did not quite live up to their first generation hype. Same thing may be said for the synthetic housewraps vs tar paper.

I'll use the term tar paper for the old style tar impregnated material known as roofing or building felt. House wrap will be used to represent any of the modern engineered weather resistant barriers.

Tar paper is not like a rubber suit. Tar paper can absorb liquid water and wick the water through from one side to the other. House wrap has engineered pores. Water vapor molecules can pass through the barrier, whereas liquid water molecules are too large to pass through. House wrap is non absorbent.

Problems may arise with house wrap if/when liquid water collects on the "back side" of the wrap. That liquid water may come from a poor installation, a leak in other words. Or that liquid water may be condensate from the interior of the house. Under some temperature conditions water vapor transpiring through the walls will remain as vapor and pass through to the exterior air. Under other temperature conditions though that water vapor will condense under the warap and be trapped there.

With tar paper if water vapor condenses on the back side the water will be absorbed by the fibers of the tar paper. The moisture will be able to wick through and evaporate.


As with many building products, synthetic housewraps were developed by companies with an eye to  building a better mousetrap. However a large component was also to make their product more attractive to mass scale home builders.. A work crew can wrap an entire home in less time using nine foot rolls of housewrap than they can when using three foot wide rolls of heavy tar paper.  That is the big attraction of synthetic wraps compared to the old fashioned tar paper.  For the owner-builder that is less of a concern.

As a note of interest, two layers of tar paper is still the preferred wrap for use with quality cement stucco installations.


Note the sidebar in the housewrap.pdf article mentioned above.

Also note:
http://bct.nrc.umass.edu/index.php/publications/by-title/housewraps-felt-paper-and-weather-penetration-barriers/
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: Jeff922 on April 29, 2010, 12:42:04 PM
My analogy is over simplified.  I was just looking at Perm ratings (Tyvek 58, tar paper 30).  I think either can be a good choice.  I hate working with tar paper however.  I used Grace Tri-Flex (a Tyvek-like "modern" roof underlayment) on my roof.  My previous roofing experiences were with tar paper.  I won't use tar paper ever again.  Tri-Flex is light (safer working on a roof), has good traction,  strong, wont rip when there is a gust of wind, one roll goes a LONG way (fewer laps), requires fewer nails, it doesn't swell and wrinkle when it gets rained on, and you can pull it tight without tearing it.  I think the ease of using a modern house-wrap shouldn't be understated.  Also, house-wrap seams (far fewer) get taped; tar paper is more vulnerable in this regard.
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: Jeff922 on April 29, 2010, 12:49:34 PM
Here's a related question:  Which product is "greener"?  I would imagine there is a lot of petroleum used in tar paper, but a lot of chemicals used in house-wrap.  Does anyone know?
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: MountainDon on April 29, 2010, 03:28:33 PM
I've never seen a good comparison on the "greenness of manufacture" question.   It would be inyeresting to see.... likely a complicated equation.


Modern building felt or tar paper (that made since the 70's) uses much less petroleum products than previously. We use products today referred to as #15 and #30 papers (# as in number). Before the first oil crisis in the 70's, felt was known as 15# and 30# (# as in pound) and contained that much tar in so many square feet. The content was reduced to save oil. Today's product still works.


Properly installed, most likely any of the building wraps will do a good job. I tend to align my self with liking tar paper over anything else for walls because of this paragraph from Paul Fisette...   "That's because I believe that under certain circumstances, felt outperforms housewrap. For example, an ice dam or roof leak may allow liquid water to get behind the felt or housewrap. It's also possible for the sun's heat to drive water vapor through the housewrap from the outside, where it can condense on the sheathing. In either of these cases, you now have liquid water on the wrong side of the wrap. Under these conditions, the liquid water would be trapped by the housewrap, which is permeable only to water vapor. Felt, on the other hand, will absorb the water, and more quickly dry to the outside."  I agree with his logic.

I was also addressing the question in terms of walls, not roofs. It may seem like a double standard but I do like some of the special-for-roofs synthetic wraps better than tar paper. My reasons are that the roofs I usually deal with are uninsulated over vented attic spaces. There's not much chance for vapor driven through from the inside to the wrap in that situation. The textured roof wraps are much nicer to work and walk on in a safety sense. Not being black they are more user friendly on sunny days.


PS, the wrinkling of tar paper when moist is what makes it preferable to other wraps when used for stucco work.  It provides a drainage plane. The wrinkle effect also aids in the air drying of damp felt.


"Housewrap" is more contractor friendly than tar paper. However, the home improvement stores around here still stock a good amount ...
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: Phssthpok on April 29, 2010, 06:32:46 PM
I was born and raised on the wet-side of the cascades, though I am not a professional builder (so you take what I say with a grain of salt). I watched my once small, homey town expand to the point of bumping borders with the next town to the east, almost 15 miles away. Woods I played in were cut down, fields I biked in 'dozed over, mom-n-pop country businesses swallowed by California style strip-malls. >:(

That being said, in the 30mumble-mumble years I lived there I have not once seen a new construction wrapped in 'tar-paper'...always with 'house-wrap'.

Make of that what you will.
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: DirtyLittleSecret on April 29, 2010, 09:02:31 PM
There is the 3rd option... Huber Zip Panels.  Yes, I love this stuff.
Title: Re: Tar paper vs. building paper (Tyvek and the like)
Post by: zion-diy on May 01, 2010, 07:41:32 PM
I vote tar paper 8).... If there is a vote.