WRB blog/article by Martin Holladay

[ThingOfBeauty]

Martin put up another one of his amazing posts today, on WRBs.
http://www.greenbuildingadvisor.com/...stive-barriers
As usual, I learned something new. It's a very comprehensive article.

[topcoatfinishes]

Interesting to read about the Zip Wall system as a barrier. I used it on my new building. Properly installed and taped, we left it to weather for months beyond the manufacturers claims. It was remarkably tight, the coating didnt fade, no swelling around the pennies, and fastener purchase was still very good.

[Ted S.]

Has anyone found the perm rating on the Zip Ply?

[worthy]

Very thorough. And now I know why we'll likely never see Zip Wall in Ontario. The tape can't be applied below 20 degrees F. This week we're seeing 0 degrees F. here and building goes on as usual. (Just add another flannel layer.)

[Lavrans]

Nice article. Not a lot new, but good to see more writing pointing out that design is more important than material. I really think that seems to be the underlying theme around everything- design first (not aesthetic, but practical) with the idea that all the protective parts are secondary lines of defense.

Thanks for posting it TOB (and for writing it, Martin)

[tucker]

Thanks for the link.

Ted, I called the Zip folks a year or two ago to ask about the perm rating. If I remember correctly the panels are comparible to osb in perm and the protective wrb layer has a perm of 16. I am just pulling this from all the numbers in my head, so might want to double check if using these numbers for a design scenario.

I have only been doing remodels/additions this past year or so but I used the zip wall sheathing one very small addition. I really like the system, the tape seems to be of a good quality. We also have been using a single layer of #30 felt over top of the zip to take care of the issue of drainage plane on head flashings, etc. I also like the idea of covering up the fasteners used on the sheathing with the felt.

Looks like I have two houses lined up for this year and I am planning to use the Zip system, a layer of # 30 felt, and a rain screen detail on the walls. We get about 60+ inches of rain with a lot of wind so exterior details are important, and I am excited and think this will be a truly bomber WRB system with a great exterior air barrier for the walls.

-2 degrees F. this morning, 130" of snow so far this year here in the WV highlands...I'll be doing interior work till' spring so I won't be taping any Zip walls till April :)

[m beezo]

-2 degrees F. this morning, 130" of snow so far this year here in the WV highlands...I'll be doing interior work till' spring so I won't be taping any Zip walls till April :)

nothing about the article, just wanted to comment on the amount of snow you guys have. That is a lot! Here is St Louis some folks are complaining about the 8 to 12 inches we got this week. And paniced about the next snow that is coming and supposed to give ua another 4 inches on top of that.

[Allan Edwards]

Yes, really good article. Martin's articles and blogs are the best I've seen, I actually like better than BSC because they are short and to the point. I like to link to them from my Facebook account to myself look smart :)

I was bantering with my project manager about sheathing, Zip Wall in particular, and based on something we heard from Steve Easely at IBS we are considering adding some type of membrane covering the bottom of our exterior sheathing. Even if it is just 10" or so. I am also think we might wrap it around the bottom end grain of the sheathing for added protection.

[tucker]

We got 260" last winter...my job-site trailors didn't move from the shop for 2 months, but my skis got a lot of use.

I've been designing/building so the sheathing and siding is atleast 16" above grade (we average a bunch of snow with huge drifts). At the bottom of the sheathing we apply z flashing turned upside down to protect the bottom edge/end grain (the stock z-flashing that is sold for t1-11 and found anywhere). Then we use an ice and water membrane on top of the first foot of sheathing lapped over top of the upside down z-flashing. The WRB then laps over the Ice and water membrane.

[Sweep8]

A Zip panel has an impregnated kraft paper surface and DuPont claims the panel has a vapor permeance of less than 1 perm and is a vapor retarder.

DuPont has gone to a lot of trouble ot discredit the Zip system (see link below):

http://www.weatherizationpartners.co...iptechtalk.pdf

Of course, what they don't show is how poorly Tyvek is usually installed.

The only tape I am completely comfortable with on a building is Grace Vycor with their water based primer.

[Ted S.]

The only tape I am completely comfortable with on a building is Grace Vycor with their water based primer.

Try Henry (Bakor) Blueskin and Carisle CCW-705 with recommended primers.

[Lavrans]

A Zip panel has an impregnated kraft paper surface and DuPont claims the panel has a vapor permeance of less than 1 perm and is a vapor retarder.

Sounds like an MDO on an OSB panel. I like MDO- it's pretty bomber stuff.

I'm a doubled #15 on walls & #30 on roofs kinda guy, though. I like double layers and stainless pans.

If they can show me some tape that's been well adhered on a real house for 50 years, I'll start relying on it. Otherwise, I'll take the Luddite stance on this one.

[Dick Seibert]

Thanks for posting that Sweep, I note that even DuPont used the term "breathability" that Martin continually challenges:

DuPont™ Tyvek® WRBs are comprised of a continuous filament barrier, precisely bonded, to provide bulk water hold-out and high breathability. When installed and integrated into a properly flashed wall system, DuPont™ Tyvek® WRBs help to guide water out of the wall and promote rapid drying.

Their pictures also show that the Zip sheathing is nothing but the much discredited OSB, now that California's VOC rules have made the flakeboard manufacturers drop their formaldehyde levels are AQ testing people are finding mold in new homes embedded into the OSB, requiring whole homes to be stripped of their stucco and sheathing. I'm going in the opposite direction, eliminating all wall sheathing to build a high quality home that is toxic-free. When Sim was building this house a lady drove up saying that she noticed that he was using plywood, she was having a new home built up the hill and they were using flakeboard, she was going right up there and tell her builder to tear that junk off and put real plywood on. He didn't hear back from here but she may have found out that her green raters required the flakeboard to "clean up the forest floor". I think society is going to look back some day and say that we built the worst quality of homes ever built at this time.

[Randy Bush]

Dick , Why in the world would anyone use a sheet damaged like the second pic on a wall? Would agree some of the stuff built today is just junk, no real lasting craftmanship in it. But then there are some really nice built house too.

[Dick Seibert]

But then there are some really nice built house too.

Agreed, some of us are trying to bring back quality, but most are building crap and gilding it so it looks like quality. The biggest problem to building well is the green code, green raters can mandate crap like OSB, and those zip walls are obviously crap with a green layer on them to make them look nice. I'm going so far as to use a steel frame to eliminate all sheathing so they can't mandate any crap and my walls can breathe. My owner has demanded that no plastic of any kind be used in his home, this is the second time I've got that, the first was way back in 1973, I was starting to build a home for an attorney, he said: "Dick, there are only two reasons that I will sue you, 1) if you kill one oak tree on my property, and 2) if a find one piece of plastic in the home".

BTW, Randy, a customer of mine went on vacation to Montana, he told me he saw some real nice new homes up there, all covered in stone, they were selling for $1,000 a square foot and were built as well as I build here.