Advantech sheathing + Commercial Tyvek VS. ZIP System
Roger_S39
| Posted in General Questions on
Hi all,
Wanted to get peoples thoughts on the following two options. While cost, and other options are important to consider, the main focus between the two is performance and longevity.
For the sake of the question/comparison, assume both options would be installed without error or damage.
The question relates to building a “forever home” in zone 4a with a desire to avoid any unnecessary future problems associated with moisture, air quality or structural integrity.
Any thoughts, or obvious standout differences between the two options, would be greatly appreciated.
TY.
Option 1:
Advantech sheathing + Commercial Tyvek
Option 2:
ZIP System
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Replies
Roger,
Will you be using your sheathing as your air barrier? If so, you will need to tape the advantech too. This immediately makes the zip option more attractive. I would opt for 3m or siga tapes rather than zip tape for OSB.
According to Huber, Advantech is a lot stronger than zip from a shear strength perspective. This might be important if you live in a high wind/seismic area. (Seismic unlikely for zone 4a but I'll never forget the 2011 earthquake of central Virginia! :-)
Roger,
Just another thought...
Adding a rainscreen gap to your wall will ensure that either wall option last a long time.
That's an excellent point Rick.
Hi Roger,
I think what you are going to get is a lot of opinions here. I guess that is what you are looking for. I'll share a few of the common arguments I hear regularly for and against ZIP Sheathing.
I'll start by saying that a lot of architects and builders with great reputations are sold on ZIP Sheathing. As I'm sure you have seen, there's a lot of backyard testing going on and as unscientific as they are, the product appears to hold up pretty darn well. Advantech has the same good reputation and many of those professionals who are using ZIP on the walls and roof are using Advantech as subfloors.
Some ZIP detractors just don't like OSB; Advantech is also OSB, so no benefit in using Advantech over ZIP if you are in that camp. Some don't trust ZIP's reliance on tape. If you felt similarly and went with Advantech sheathing, you could use a fluid applied product to seal the seams, assuming that you still want to use the sheathing as your primary air barrier for your walls (but you can do the same with ZIP). Some folks prefer to be able to mechanically integrate the WRB with flashings, which you can do if you use a housewrap.
The only other things I can think of to consider (besides cost) is that housewrap is tough to detail well as an air barrier and not recommended for that and the work is likely to get done quicker with ZIP Sheathing.
Hi Brian,
Thanks for the reply.
If we take real world construction handling/possible damage into consideration, do you think:
The end result would be "better" (in terms of water and air "sealing") going with ZIP and risking the non green side getting wet or green side damage or over driven nails, OR: Going with Advantech and rolling the dice with Commercial Tyvek install with regards to "housewrap is tough to detail well as an air barrier"?
Thanks.
You are getting some good advice here, but ultimately, you'll have to make the call. I simple wouldn't reply on staple-up housewrap as an air barrier. So if you don't want to use ZIP, it's either make the sheathing into your air barrier by detailing the seams, or as Jon suggested, you could use a self-adhering WRB. Rick is also correct that you definitely need a rain screen space between you wall and the brick. There are a number of ways to do this. I recommend you read this article: https://www.greenbuildingadvisor.com/article/flashing-brick-veneer
I pick option 3:
Taped plywood with fully adhered Blueskin VP100 WRB.
What do you like about that option Jon?
a) taped solid materials make for a good air barrier (Zip also provides this)
b) plywood is more durable than OSB (although Huber's OSB is better than most OSB so who knows)
c) fully adhered overlapped WRBs outperform staple on (and probably Zip)
d) materials cost is lower ??
e) VP100 + plywood has a good perm value (reasonable outward drying without excessive vapor drive to the interior)
Downside - I'd expect a little more labor.
Thanks Jon. I think the self adhering WRBS are a good option in a lot of situations too.
Hi Rick,
Thanks for the replies.
"Will you be using your sheathing as your air barrier":
My understanding was if Advantech was used with commercial Tyvek wrap, the wrap would be the air barrier and it would get the Tyvek tape over the wrap overlap joints. Yes/No? If so, would it still be a good idea to tape the sheathing joints behind the commercial wrap?
"Adding a rain screen gap":
Brick would probably be the main exterior veneer which doesn't require a rain screen. Correct? If any Hardie was to be used, that's where the screen is added. Correct?
Out of curiosity: Cost - Would one option be far superior over the other and hence worth the cost difference?
Thank you
Roger,
Brick is considered a "Reservoir Cladding" and will require special design considerations if you want this wall to last a long time.
You live in a tricky climate with cold winters and hot, humid summers.
If it were me, I would probably opt for zip system then 2" inches of foil-faced Polyiso (seams taped) a dimpled drain matt and then my brick cladding.
The brick definitely needs an air gap. Also, I would never rely on my housewrap to be my air barrier... It sees too much abuse.
https://www.greenbuildingadvisor.com/article/when-sunshine-drives-moisture-into-walls
Awesome info Rick.
In regards to "inward solar vapor drive, vapor diffusion from the outside inward": would there be a difference in the level of this problem depending on the use of brick vs a Hardie type product?
Is there any exterior veneer option that would help limit/remove this problem compared to brick etc.?
Hey Roger,
I'm no expert on inward solar vapor drive but I suspect that 3/8" fiber cement would hold far less water than conventional brick. You can also nail it to 1x3 strapping or through "cedar breather" to make a rain screen gap. This would be far easier than a safe brick detail.
But brick is beautiful and zero maintenance!
If you lived in a warmer climate then you could simply put the dimple mat against your sheathing and then add the brick cladding. But that might lead to sheathing rot in your climate during winter/spring- especially in humid rooms. This because I believe the dimple mats are all class I vapor retarders. (That's why I would opt for at least 1.5" of exterior rigid foam to keep the sheathing below dewpoint).
If you want your walls to last many years then include a rain screen gap. The bigger the better.
Cost comparison for pricing where I am in Upstate NY would be $1 per sf for 1/2" Advantech Square edge Structural 1 and Tyvek Commercial. 7/16" Zip is $0.60 per sf plus tape. Depending on job size it may be a little bit of money or a lot of money. Typically I look at Tyvek as installing it twice because it always comes loose from the wind and is far more labor intensive than Zip. My own personal house, and everything I spec on projects is always Zip.
You are doing something wrong if the Tyvek comes loose after installation.
Malcom, can you elaborate? I regularly see Tyvek dangling off the side of new construction in "middle class" developments. What are they doing wrong and how can it be prevented?
Nick,
When I look at new construction projects around town it seems like they are all using conventual staples to hold down tyvek. The wind then rips the housewrap off the staple leaving a small hole.
The correct way of course is to use cap staples spaced appropriately.
Nick,
I see the same thing here. Tyvek installation guides call for cap-nails on a specific spacing. I bet none of the houses you've seen stuck to it.
Tyvek Commercial is also a completely different animal to regular Tyvek. It's much harder to tear, making both the initial installation easier and problems with exposure before it is covered much less likely.
Edit: Rick beat me to it.
Since Advantech looks to hold up to moisture better than Zip, what are thoughts on the pros / cons of using Advantech sheathing with Zip tape, no Tyvek?
If taped, could Advantech be both WRB and air barrier?
Advantech does not meet the requirements for a WRB in IRC R703.2, nor does Huber advertise/specify it as such.