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Interesting question on tyvek and felt paper for roof

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#5 · (Edited)
I would think it would be a massive waste of money since roofing material is typically more waterproof than siding installations. Never seen a roof with weep wholes. Except the ones the europeans post with gutters that run inside the home. That still amazes me.
 
#6 ·
From DuPont's website:

9. Can DuPont™ Tyvek® be used in attics? On roofs? Under Floors? On the interior?

In 2006 DuPont introduced Tyvek® AtticWrap™, a unique, breathable membrane that helps create an airtight seal to reduce air leakage and energy loss through the roof. All other DuPont™ Tyvek® products in Canada and the US have been tested and approved as a product to be installed behind exterior walls.
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Discussion starter · #13 ·
The question would now be, if tyvek is a water barrier on walls, why won't it be a water barrier on a roof? Even though shingles stick to tar paper and seal, isn't tyvek just as good as sealing when using staples?
 
#14 ·
enforcer said:
The question would now be, if tyvek is a water barrier on walls, why won't it be a water barrier on a roof? Even though shingles stick to tar paper and seal, isn't tyvek just as good as sealing when using staples?
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Well sure it would keep the water out but what is the sense...buy synthetic if you are just wanting to waste your money. Hell, you can use old grocery bags if you so desire......I have seen it done!
 
#17 · (Edited)
RandyB1986 said:
on a different but same note, why do some old timers use black paper on walls instead of Tyvek?
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Because some of us "old timers" started using felt, made the switch to Tyvek and after several years, were not impressed.

Felt has some properties that plastics don't and that's why I prefer it.

http://bct.eco.umass.edu/publicatio...u/publications/by-title/housewraps-felt-paper-and-weather-penetration-barriers/

from the link


Housewrap or Felt?
Based on our testing, if I were buying a housewrap today, I would choose either Tyvek or R-Wrap, because they display the best water resistance. But so far, I’ve avoided the million dollar question – housewrap or felt? The truth is, there’s not million dollar answer. In general, I don’t think it matters a whole lot. If you get the flashing details right, and are careful installing the building paper, you will prevent 99% of the moisture problems caused by wind-driven rain and snow. Either product, housewrap or felt, will provide an adequate secondary drainage plane. And either product is permeable enough to allow interior moisture to escape.
As it happens, I have felt paper on my own home, and if I could choose between felt and housewrap and do it over again, I’d still choose felt. 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.
 
#18 ·
be honest with you Riz the main reason i use it is it's superior rip resistance,less fasteners needed less penetrations into the envelope,tears and damage easier to fix,integrates with SA tape flashings

and lighter weight,easier it is to use the better it can be installed imo

other reasons are it won't absorb like felt,i know this is exactly opposite of your view;)

otherwise i think they are both suitable for wall wrb


that umass thigs been around for years by the way:rolleyes:not impressed
 
#19 ·
For walls, tyvek has a much higher perm rating than felt.
If felt gets wet,it's perm rating rises dramatically but there is a catch most don't know about. Felt has tiny little holes and as it gets wet, these holes expand make it more permeable..sounds good right. Not really. When those holes expand, water is able to get through. I will stick to tyvek on walls and 30 lb felt on the roof.
 
#20 ·
Tom Struble said:
be honest with you Riz the main reason i use it is it's superior rip resistance,less fasteners needed less penetrations into the envelope,tears and damage easier to fix,integrates with SA tape flashings

and lighter weight,easier it is to use the better it can be installed imo

other reasons are it won't absorb like felt,i know this is exactly opposite of your view;)

otherwise i think they are both suitable for wall wrb


that umass thigs been around for years by the way:rolleyes:not impressed
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It's been around for years, but the reality hasn't changed. We can beat this thing to death. The only reason I even bother is to make people aware of their options so they can make an INFORMED decision on what product to use.

I base my decision on my own personal experiences and observations, as I know you do. We have opposing views, but both of us sleep well at night knowing we've made the right decision.:thumbsup:
 
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