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Tyvek vs. Typar

Nailbag's picture

What are the differences performance wise. Which is more breathable?


Which holds up longer to UV and weather?


I'm cedar shingling my house and expect to take a while to do it!


 

(post #93131, reply #1 of 6)

FC...


Picked this up on an earlier thread here.


http://www.umass.edu/bmatwt/publications/articles/housewraps_feltpaper_weather_penetration_barriers.html


He really puts thumbs-down on Typar, but my framer insists on it for a similar job this fall...he'll dry in and I'll side.

(post #93131, reply #2 of 6)

with either one, be sure to keep an air space between your Cedar and it.

The tanins in the Cedar can break down the Tyvec/Typar ability to shed water (in other words, ruin it).

If you fir the whole thing and keep the Cedar away it'll be fine, or just use tar paper.

also, remember that soaps will also attack the Tyvec/Typar type product's ability to function as a water barrier (soaps are surficants just like tannins are). So, if you ever power wash your walls with soap you could harm the stuff, even if you did make a proper air space with firring strips. If you are concerned about this, just use tar paper.

Norm

(post #93131, reply #5 of 6)

Hmmmmmm....


Sounds like the jury is out on this one.


I think that furring out SIDING is excessive...the cedar shingles are like to wear due to wind and sun before they rot.  And as far as cedar ruining the housewraps ability to shed water, I think that happens when you puncture the stuff with a gazillion staples.


So, looks like I'll buy the cheapest housewrap so I can hang shingles in my own good time and throw some felt up if the stuff starts to decay.


Screw it....I've got 18" eaves.  Hehehehehe 


Thanks for the help though. Excellent food for thought.

(post #93131, reply #6 of 6)

If the link johnnyd posted is the one I think it is, it recommends 2 layers of saturatead felt. Not a hands down this is surely the best, but a recommendation none the less. The felt made for this application and required in many places as a stucco underlayment is "grade D" felt. The jury isn't out, there is wide spread agreement that a continuous drainage plane behind the siding is the best way to go (i.e. the furring strips you dismissed). Problem is, it adds additional costs and it is difficult to convince homeowners that the extra cost is worth it. The cost difference between tyvek and typar is worth the extra for a better product, and tyvek is the superior product of the two. But I would still use the double layer grade D.

(post #93131, reply #3 of 6)

http://www.heritagefoundation.ca/gshingle.htm :

"a three-dimensional nylon or plastic mesh which provides a continuous air space between roof deck and the shingles. This eliminates excess moisture, reduces potential rotting and warping, and allows entire underside of shingles to dry. Cedar breather also eliminates the need for furring strips laid under the shingles. "


  I have seen it used extensively under roof shingles (shakes) and a few times under strip cedar siding.  I am not sure about the uniformity under shingle siding though.


 

 

(post #93131, reply #4 of 6)

We have recently switched to Typar from Tyvek.  I believe Tyvek to be a good housewrap, but the benefits of Typar (doesn't tear easily, easier on the eyes when you are siding in the sun, and some other benefits) outweighed the benefits of Tyvek for us.  Typar is about $15-20 cheaper. 


Also, you can use Typar behind cedar.  I may be wrong about that, but when I researched it, I remember being able to use it behind cedar.


 


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