Tyvek Roof Wrap

Hardibuilt

Has anyone used the Dupont Tyvek Attic Wrap? The Tyvek wrap is placed on top of the roof trusses/joists before the house is sheathed. It is suppose to make a house up to 30% more efficient. Of course the wrap is expensive at about 200 bucks a roll. I think a roll is 4 x 100.

There is an installation video on the Tyvek site.

Let me know what you guys think.

CheckmateOhio

How would tyvek on top of the rafters make it more energy efficient? The line of insulation is usually at the ceiling joists and the attic is vented. ????

Same Old

Looks like a great idea.

http://www2.dupont.com/Tyvek_Constru...atticwrap.html

I'll probably try it.

reveivl

Great! Interior gutter system. Now you can cheap out on the roofer.

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mikesewell

30%? Sounds like horsesh*t.

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Grumpy

I really don't see the point, nor can I figure out how it's supposed to work.

skyhook

The breathable metalized surface reflects away the heat during the warmer months and holds in the radiant heat during the colder months, also insures a tighter envelope.

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Grumpy

Are we not supposed to be venting the heat from the attic including in the tiner time when hot air holds moisture and migrates into the attic space? If the wrap, sitting loosly on the bottom of the roof deck creating pockets in each rafter, then reflects the heat into the attic space will it not be also causing the insulation and exposed framing to become saturated with humidity? Will this metalized vapor barrier be blocking air from the attic area from exhausting through the vnetilation?

skyhook

Typical Tyvek house wrap is a air and moisture barrier yes, the metalized roof material is breathable to let air and humidity pass through.

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Grumpy

I kinda figured that... but here is a hang up. Hot air holds moisute, to that I am sure we can agree. And it reflects heat, thus reflecting moisture as well?

Perhaps I am wrong, but as I think about it, that's where I keep ended up. This design will trap moisture. I have the same hangup on those attic envelopes where the rafters are sprayed with closed cell foam insulation. Where does the mositure go?

joasis

I saw Tyvec placed on a roof deck before a standing seam panel roof was installed, but it looked just like standard house wrap. Commercial building...I would have liked to have stopped and asked why, but I never had the time.

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Hardibuilt

A builder friend of mine is using the product and he thinks it is helping sell his homes. They even have a monitoring system to show the decrease in heat up in the attic. I see the benefits in heating and cooling, I didn't know if moisture would be a problem or not.

housewapper

Properly installed, DuPonts attic wrap does not creat air "pockets."

I suggest you all watch the video of its installation at DP's site.

Contrary to the notion of air "pockets," the use of rafter caps go on top of the wrap, on top of the rafter, pushing it down between the rafters to create a channel for the ventilation. It allows vapor (water molecules) to escape.

The actual method of weather resistance is that water itself has a tighter molecule composition, it can't penetrate the paper. When it turns to vapor, the molecules separate, thus each alone is able to pass through the paper. Physics.

Ten Fingers

Make yourselves aware of it. Because of its cost to install, it may be rare for a while. But if your customer with money and some knowledge of it asks for it, you won't feel like a dumb dumb if you at least know a little about it.

I don't mean to sound like I'm preaching. Just glad I learned of it from a salesman a while back

marklo154

i hope i never have to use that, sounds like a pain in the a##, watch it will probably be spec`d in the next job hahah

Big Bob

Interesting?

For this system to work on a Hip roof ALL ridges need to get ridge vent.
Anybody ever put ridge vent from eave to peak on a hip roof?

Should be good for re-roofing biz. Lets cook some shingles?